- Email: [email protected]
Spontaneous premature rupture of the membranes
SPONTANEOUS PREMATURE RUPTURE OF THE MEMBRANES*t CHARLEs
E.
FLoWERs, JR., M.D., CHAPEL HILL, JAMEs F. DoNNELLY,
~I.D., \'\TrNsToN-SALEM, RoBERT t~. CREADRICK, ~v1.D., DuRHAivi,
BERNARD G. GREENBERG, PH.D., AND H. BRADLEY WELLS, M.S.P.H., CHAPEL HILL,
N.c.
(From the Departments of Obstetrics and Gynecology of the University of North Carolina School of Medicine, Chapel Hill,- Duke University School of Medicine, Durham,- Bowman Gray School of Medicine, Winston-Salem, and the School of Public Health of the University of North Carolina)
1 AST year there was presented to this Association the first report of the coL operative Perinatal Mortality Study which is being conducted by the Ikpartments of Obstetrics and Gynecology of the University of North Carolina. Duke University, Bowman Gray School of Medicine, the School of Publie Health of the University of North Carolina, and the North Carolina Statf• Board of Health. This paper 1 emphasized the primary importance of sociocconomie factors in perinatal mortality and indicated that a sizable number of perinatal deaths were associated with spontaneous premature rupture of the membranes. A further study of this problem was thus stimul11tecl.
Method of Study The data for this study were obtained from the three cooperating medical schools and are based upon 7,511 deliveries of infants weighing 400 grams and above, which occurred between 1954 and 1956. 'fhe tabulations are taken from 763 study schedules based upon interviews and hospital records of single births with known birth weight and known latent period in the cases of spontaneous premature rupture of the membranes before the onset of clinical labor. In each tabulation of a given item, the unknowns have been excluded from the total. The study schedule is a 6 page booklet plus a supplement for recording autopsy findings. Information for the schedule is obtained from the hospital reeords and by direct interview with the mother. A study schedule is prepared for all fetal and neonatal deaths occurring in the three University hospitals. A comparison study schedule is also completed for approximately every fifteenth infant who survives the neonatal period. The comparison group is selected in such a manner that the obstetrician is not aware of which infants will serve as controls until after delivery. Perinatal mortality in this study refers to all deaths of infants weighing 400 grams or more through the twenty-eighth da.'T of life. The statistical methods employed in the study have been reported by \Vells, Greenberg, and Donnelly. 2 •Supported in Part by a grant from The Children's Bureau. Appreciation is expressed to Dr. A. H. Elliot of the North Carolina State Board of Health for his assistance in this study and his administration of the grant. tPresented at the Twentieth Annual Meeting of the South Atlantic Association of Obst"tricians and Gynecologists, Hollywood, Florida, Feb. 1 to 5, 1958.
761
!•'LOWER~
762
ET A L.
\rn. /. t )b"t ~ ()._ 0\..'t
Incidence The reported incidence of premature rupture of the membranes varies widely according to geographic locations. Di Guglielmo and Pepe'1 reported an incidence of 5 per cent in Argentina, while Embrey 4 reported 13.9 per cent in England and Kjessler 5 18.9 per cent in nothenburg, Sweden. In the United States, Cron and Brown'5 have reported an incidence of premature rupture of the membranes of 9 per cent while Eastman 7 has reported 12 per cent and Calkins8 14 per cent. GENERAL DATA AND INCIDENCE OF PREMATURE RUPTURE OF MEMBRANES NORTH CAROLINA PERINATAL MORTALITY STUDY 1954-1956 All Deliveries
II All single bnths 1 koo•n latent oeriod. birth weiaht. and rupture ·at meinbranes ~ ·
~All.
I 'w•• I deh11et1es
Over 2000
Over 2000 grams
Non-premature
Non-premature
32.9%
15.8% Premature
rupture of
membranes
Premature rupture of membtones
Non-premature rupture
Non-premature rupture
rupture
ropture
grams
23
IB 7%
Premature rupture of membranes
Non~premoture
rupture
74
15.4%
Premature
Premature
membranes
membranes
rupture of
rupture of
Fig. 1.
Fig. 1 depicts the incidence and importance of premature rupture of membranes in this study. The over-all incidence among the deliveries in the three medical schools was 15.8 per cent. However, 75, or 26.7 per cent of all the fetal and neonatal deaths, were associated with premature rupture of the membranes. This complication occurred in a~sociation with the birth of 32.9 per cent of the infants who weighed 400 to 2,000 grams and 18.7 per cent of those who weighed 2,001 grams and above.
Concurrent Obstetrical Complications A study of the 52 deaths of infants weighing 400 to 2,000 grams and the 23 deaths of those weighing 2,001 grams and above with premature rupture of the membranes disclosed a sizable number of other major obstetrical complications (Table I). These obstetrical complications assume added significance when they are converted into percentages of occurrence. Of the 75 fetal and neonatal deaths,
\'olume 7f• \.umber -t-
SPON'l'ANEOUS PREMATURE
RUPTFRJ<~
OF MEMBRANES
there were 2.t-, or 82 per cent, complicated by infection. There were 20 mothers, or 26.7 per cent, in the same group who had premature separation of the plaeenta, 111pture of thP marginal sinus, or other significant antepartum bleeding. Approximately one half of these hemorrhagic complications, however, occurrpd in mothers whose infants weighed 400 to 1,000 grams. Eighteen, or 24 per <•enL of all eases of fetal and neonatal death with premature rupture of the membrane:-: were complicated by toxemia of pregnancy. The umbilical cord prolapsed. in 16, or 2l.B per cent of all the cases, hut this eomplication was responsible for the death of the infant in only 10.7 per cent of these 16 cases. Intrauterine •lea11t had occurred in the other cases prior to prolapse of the cord. 'l'ABLF:
L
MAJOR OBSTETRICAL CoMPLlCATIOKS AssociAT~:p
\\'JTll
Pru;MNrrnE RPJ"rna: ot·
~'liE ~!EMHBAKES
1Nr'A:NTH
COMPLICATIO:N
-:---:-:-:
Antepartum or intrapartum fever above 99° F. Premature separation of the placenta, rupture of the marginal sinus, or other signifirant antepartum bleeding oeeurring before premature rupture of the membranes Premature separation of the placenta, rupture of the marginal sinus, or other significant antepartum bleeding ON'UITing after premature rupture of the membranes 'l'oxemia of pregnancy Prolapse of the umbilical cord Congenital anomalies incompatible with life Idiopathic fptal death in utero preceding rupture of the nu•m branes Uirrumvallah· pla<·<~nta Diabetes Polvhvdramnios Ute'ritie inertia Abnormal pr··~entations Breee.l1 Face or Brow TransvPrse Lie ------~~~--~---------------Total fptal and nPonatal deaths in cases of premature rupture of nH'mhraneR Th<' total
i~ le~~
than the
~urn
1
.fll0-:!,001) mL\MF: JS
Jl\"r'AK1'N
1 :!,000 CHC\:11:'1 _j__,\_~l___-~!~1\'f~ ti
..
1~
II
;}
II 11
,)
:l
.)
~
l II
il II ~0
,,
Hi
in eaeh column because of multiple complications
Abnormal presentations were associated with 27, or 36 per cent, of the 1otal deaths in cases of premature rupture of the membranes. This complication was also assoriated with other lethal obstetrical conditions and contributed to a death rate of 81.82 per 100 deliveries of infants weighing 2,001 grams and above. This is shown in 'l'able II where it is seen that the death rate in a similar weight gToup with obstetrical ('omplications was onl~' 4.26 prr 100 deliveries when the tnrmhrarws had not ruptured prematurel:v. TAB!,"
li.
l>F.A1'H RATE t'ER
DELIVERIES OF lNFAKTS \\·r,H;HISG :!,00] GHAMS AXIl .\J!fiVf; ACCORDING TO PRESENTM'IOX .
]00
KO PREMATURE Rl'PT\'RE OF MEM!lRANJ<;S
Tot!!] VPrtt'x AU others
1.74 1.5R 4.26
l'R~:MATTJHE
Rl'PTU!tF: OF MEMBRANES
:n.R:!
------------------------
DPath rat!'~ in this anu all other tables are romputed by thP following equation: ERtimated pPrinatal mortality rate per 100 delivPries = Numher of fetal and neonatal deaths x 100 NumbPr of fetal and neonatal deaths -+ Pstimaterl numhPr of s'urvivorR-
-\m .. L (Jbo.t. & (hnec October, 195R
PLOWERR ET AL.
764
Role of Premature Rupture of the Membranes in Perinatal Mortality Since there was a high incidence of obstetrical complications associated with premature rupture of the membranes, eaeh case was studied to determine whether rupture of the men1branes vvas the Jnatior or initiating cause of death. TABLE
Ill.
CASES IN \VHICH PREMATURE RUPTURE OF THE MEMBRANES WAS NOT 'fHE MAJOR OR INITIATING :~<'ACTOR IN PERINATAL DEATH
CAUSE
0~'
HEATH
Premature separation of the placenta, rupture of the marginal sinus, or significant antepartum bleeding occurring before rupture of the membranes Congenital anomalies incompatible with life Idiopathic fetal death in utero occurring before premature rupture of the membranes Intrauterine anoxia associated with severe toxemia of preg-
IN~'ANTS
INFANTS
400-2,000
~.001 flRAMS
GRAMS
AND ABOVE
12 3
3 5
~
3
2
0
il 2
2
0
52
23
spontaneously
fetal and neonatal deaths in cases of premature rupture of membranes
It is evident from Table III that premature rupture of the membranes was not a major factor in the death of 21, or 40.4 per cent, of the infants weighing 400 to 2,000 grams and in 16, or 69.6 per cent, of the infants weighing 2,001 grams and above. Premature rupture of the membranes was merely an incidental occurrence. The infants actually succumbed to other lethal obstetrical complications such as premature separation of the placenta, toxemia of pregnancy, maternal diabetes, heart disease, congenital anomalies incompatible with life, and to idiopathic fetal death in utero occurring before rupture of the membranes. TABLE IV.
CASES IN WHICH PREMATURE RUPTURE OF THE MEMBRANES WAS THE POSSIBLE MAJOR OR INITIATING FACTOR IN PERINATAL MORTALITY
CAUSE OJ<' DEATH
Neonatal deaths associated with amnionitis, atelectasis, and/ or hyaline membranes Intrauterine deaths associated with amnionitis and/or intrauterine pneumonia Prolapse of the umbilical cord (primary cause of death) Premature separation of the pla('enta after premature rupture of the membranes Intracranial hemorrhage (labor initiated by premature rup· ture o:f the membranes) Total Total fetal and neonatal deaths in cases of premature rupture of membranes
INFANTS
INFANTS
400-2,000
2,001 GRAMS
GRAMS
ANP ABOVE
11
1
7 6
4 2
5
0
2 31
0 7
5~
23
A review of the 75 deaths also showed that 31, or 59.6 per cent, of the infants weighing 400 to 2,000 grams, and 7, or 30.4 per cent, of the infants weighing 2,001 grams and above were possibly lost as a result of premature rupture of the membranes.
Volume 7G
!'JumbN 4
SPONTANEOUS PREMATURE RUPTURE OF MEMBRANES
Intrauterine Infection, Latent Period, and the Duration of Labor Intrauterine infection was the major cause of death in the cases in whirh the pet·inatal mortality was relate~ to pre.matur~ ruptur~ of ~he m~mbranes. The 1nembranes are an effective barr1er to 1ntrauter1ne 1nfect1on; but \Vhrn mpture occurs, bacteria invade the amniotic sac in a matter of hours. Once severe amnionitis is present, it may cause the demise of the infant from intrauterine pneumonia or contribute to pneumonia and atelectasis in the neonatal period. Moreover, the association of premature rupture of the membranes, fever, intrauterine anoxia, or other major obstetrical complications will in(•reasc thf' amount of aspiration of the amniotic contents and increase the likelihood nf pulmonary infection. Amnionitis and intrapartum infection contributed to 23, or 30.7 per eenL of the 75 deaths associated with premature rupture of the membranes. It <'allnot h<' stated that amnionitis or intrapartum infection was the real cause of death nf thr infants weighing less than 2,000 grams; prematurity alone could han been the lethal factor. But premature rupture of the membranes and a prolonged latent period were undoubtedly major fMtors in the 5 deaths of tlw largrr infant~':. Guilbeau and Eastman 7 have carefully evaluated the effert of the lah•n\ period on pe1·inatal mortalit;v in eases of p~emature rupture of the memhranPs. Tlw,v havP concluded that the duration of the latent period is not a signiflean1 factor in infants below 2,499 grams be(•ause of the major significanee of pl'('" maturity. In mature infants, howen~r, a latent period of 48 hours and gTratPr is assoriatecl with a threefold increase in perinatal mortality. The nnmber of cases in this series is small compared to that of GnillH~au and Eastman, but there is a elose correlation in the findings. Table V l'jhO\VS the percentage of infants vvith -rarions late.ilt periofls a(•(•nr1l ing to weight. TABLE V.
LATENT PERIOll 1:-i CAS~;s OF PRF:MA'l'l'RF; Rla"l'UR~; 0~' 'rHE JHE~1BRA.Nlcfl
BIRTH WEIGHT
____(g_!t~~
Perinatal Deaths.400-2,000 2,001 and above
TOTAL
0-11 HOURS
--'~~-N_O_.~----'--~---'(% L_ 52 23
I l!.l<~i) l
HOURS
((!£)_ ___
lOVER
35 Il~Yl'l~~;
L __ ~ \
15.4
l7.il
52.~
~n.1
:.:!-1 .7
7il.O
:20.:1
li.i
67.:-t
Survivors (Controls).400-2,000 and above
0 74
Only 32.7 per cent of the mothers who were delivered of infants in the lower weight group had a latent period of less than 35 hours. The average latent period in the cases in which the infant died in this weight group was 9 days. Essentially 90 per cent of the 97 infants with premature rupture of the membranes who weighed 2,001 grams and above had latent periods of 35 hours and 1ess. The latent period was longer than 36 hours in all cases of infants in this weight group with premature rupture of the membranes who died of amnionitis or intrapartum infection; in fact, 2 had latent periods of 38 honrR, one of 6 days, one of 7 days, and one of 9 days. In the weight group over 2,000 grams, the mothers of surviving infants had, on the aYerage, a shorter latent period than the mothers of infants who di
FLOWERS ET AL.
766
Am. /. ()h:q, &. Grnec.
October. 1958
Table VI gives a computation of the mean hours of labor in cases of fetal and neonatal death and of surviving infants with or without spontaneous premature rnpture of the membranes. TABLE Vl. MEAN HOURS OF LABOR IN CASES OF FETAL Al'\D NEONATAL DEATH AND SuRVIVI.:-!G INFANTS WITH AND .WITHOUT SPONTANEOUS PREMATURE RUPTURE OF MEMBRANES NO PREMATURF. RUPTURE OF MEMBRANES
Fetal and neonatal deaths 400 to 2,000 grams 2,001 grams and above Surviving infants 2,001 grams and above
-----'-
PREMATURE RUPTURE OF MEMBRANES
9.1
8.6
10.7
16.8
8.9
7.4
In the cases of surviving infants who weigh 2,001 grams and above there actually appears to be a reduction in the mean duration of labor with premature rupture of the membranes. But the mean duration of labor is increased for all infants in this weight group who died, and is almost doubled with premature ruptu.re of the membranes4 Thus premature rupture of the membranes has a favorable effect on the duration of labor only in surviving infants. Prolapse of the Umbilical Cord
Of the 75 deaths studied in Table IV there were 8 deaths, or 10.7 per cent, which were possibly the result of prolapse of the umbilical cord in association with premature rupture of the membranes. All of these infants had some abnormality of presentation, either footling' breech, transverse lie, or floating vertex. These deaths n1ight have occurred if the men1branes had rl1ptured dnring labors not complicated by premature rupture of the membranes but whether or not in this magnitude is not known. The data concerning prolapse of the cord are included for completeness. It is difficult, with the paucity of data, to determine its absolute significance in the problem of spontaneous premature rupture of membranes. Errors in the Management of Cases of Premature Rupture of the Membranes It is possible to criticize the obstetrical management of some cases in any series of perinatal deaths, particularly when the deaths are associated with a number of major obstetrical complications. This series is no exception. There were 18, or 24 per cent, in which there were thought to be errors in obstetrical management (Table VII). Only 8, or 10.7 per cent, of these cases were unquestionably associated with the problem of premature rupture of the membranes. Delivery of the breech was poorly and 11nskillfully managed in the case of one infant weighing 1,600 grams and of another infant weighing 3,800 grams. Cesarean section would have been preferable to version and extraction in the case of a 2,700 gram infant with a latent period of 36 hours and a transverse lie. There were 3 cases of maternal diabetes the management of which are open to criticism. One infant weighing 1,700 grams died as a result of totally inadequate care by the referring physician. Two other mothers with breech presentations of infants weighing 2,800 and 3,800 grams should probably have been delivered by cesarean section at 38 weeks. Two immature infants were lost as a result of the mismanagement of severe maternal rheumatic heart disease with failure. One case of uterine inertia was poorly managed during labor and delivery. One patient with intermittent fetal distress was observed for 2 hours before a sterile vaginal examination disclosed the cervix to he 4 em. dilated and the cord prolapsed.
\.(dume 76 \jnmher 4
TABLE VJI.
KPONTANEOUS PREMATURE RUP'fURE OF MEMBRANES
7fli
ERRORS IN THE OBSTETRICAL lVIANAGEMEN'l' 0.' CASES \VITH PREMA'l'f)RE Hl'P'I'Illif: O~· MEMBRANES lN~'Al'\TS
400-~,000
mtA::IiS
ERRORS IN MANAGEMENT
improper rnanagerrwnt of abnormal presentation~: Breech Transverse lie Improper treatment of maternal diabetes Improper treatment of rheumatic heart disease rmproper management of uterine inertia [mproper management of prolapse of the umbilical eon! Failure to treat intrapartum infection with antibiotir•s an•l
0
1 II
n
1
l
0
.j
]II
The Treatment of Infection Twenty-four, or 32.0 per cent, of the mothers of the 75 infants who died after premature rupture of the membranes had antepartum or intrapartum infection. Fourteen of these 24 infants with infection were alive at the onset of labor and 8 of them were not treated with antibiotics and/or oxygen during labor. Guilbeau and Eastman' have presented condusive data that the administration of penicillin during the latent period has no effect on perinatal mortality. It appears that the use of the wide-spectrum antibiotics would also be ineffective "1 • •, uurmg me wno1e latent penoa; tney may oe contrammcatea smce tne oatance of the bacterial flora would be affected. The use of wide-spectrum antibiotics, however, becomes mandatory after the onset of infection during the latent period and during labor and the puerperium. It also seems reasonable to administer 40 per cent oxygen to mothers who have an elevation in temperature of 100° F. or more during labor. An elevation in temperature increases the metabolic need of the infant for oxygen and its administration to the mother will increase the partial pressure of the circulating oxygen and improve its passage across the placenta. The parenteral administration of tetracycline or chloramphenicol and the use of oxygen may not have prevented these 8 deaths. It is felt, however, that there are good theoretical grounds for the use of both agents and that the,\· should have been used. ~-
1
~
...
•
•
•
.,.
•
..
•
•
., •
•
...
..
• ...
't
..,
Socioeconomic Factors
PreYious review of the material in the North Carolina perinatal mortalit~· study revealed that socice{lonornic factors '\Vere. probably of major in1portance in the causation of fetal and neonatal deaths. Since premature rupture of the membranes is so intimately associated with the problems of prematurity and obstetrical complications, an analysis of the data was made for parental and en \'ironmental factors. Table VIII is a study of the percentage distribution of cases of infants weighing from 400 to 2,000 grams according to race, father's occupation, and mother's education. It was impossible to compute death rates according to these factors since there were insufficient controls in this weight group. Death rates would have had little meaning since prematurity is of ri1ajoi· importance in this class of infants.
FLOWERS BT AL.
768 T.\BLB
Am.]. OG:::.t. & Cynec. October, ]91;"8
SocioEcoNOMIC FAc·roRs IN .F'ETAL-NEONATAL D~~ATHS m' 400-2,000 VIII. INFANTS WITH AND WITHOUT PREMATURE RUPTURE OF THE MEMBRANES ACCORDING TO PERCE~TAGE DISTRIBFTION m' CASES NO PREMA'fURE RUPTURE OF MEMBRANES
PREMATURE RlfPTURE
GrtAM
m'
MF:MBRA~E;S
Race.Total White Non-white
100.0 67.3 32.7
100.0 50.9 49.1
100.0 21.] 37.9 41.1
100.0 19.1 31.9 48.9
100.0 213.6 55.6 20.8
100.0 13.8 44.8
Father's Occupation.Total Group 1 Group II Group III
Mother's Education.Total 13 or more years 9-12 years or less 8
Premature rupture of the membranes in the smaller weight groups occurred more frequently in the non-white race. This is evident in the analysis for race and for mother's education because the majority of patients who had 0 to 8 years of schooling were non-white. The father's occupation was classified in three groups. Group I consists of professional people, managers, officials, proprietors, and students in the Universities. Group II consists of clerks, sales workers, craftsmen, foremen, and operators. Group III includes farmers, farm laborers, other laborers, and household workers. It is clearly evident that the largest portions of the fetal and neonatal deaths of these small infants, with and without premature rupture of membranes, occurred in the lowest socioeconomic group. But the difference between occurrence and nonoccurrence of premature rupture of the membranes was so slight that it is difficult to say that the event itself is related to the father's occupation. There were sufficient control infants weighing 2,000 grams and above to allow calculation of death rates for various socioeconomic factors in these cases. TABLE TX.
__
DEATH RATES PER HUNDRED DELIVERIES BY RACE OF ALL INFANTS ABOVE GRAMS \VITH AND WITHOUT PREMATURE RUPTURE OF THE MEMBRANES AccoRDING TO FATHER's OccuPATION
2,001
_:._OC::._:C~U:._:P:._:A:__T_IO_N___:G_:__R_O_UP_ _ __,_____N_O_P(_~;_M_:::_:_,~_:_~_\.~~~TU~--l- . PR~~A:~~B:z::~RE White.I
1.17
II
1.99
Ill
1.6]
1.08 0.76 6.17
1.02 2.84
11.29
Non-white.! II
III
2.13
Table IX presents interesting data concerning the relationship of the father's occupation to premature rupture of the membranes. When this complication occurs with infants over 2,000 grams of mothers in the upper economic
Volume 76 Number 4
SPONTANEOUS PREMATURE R.UPTURE
OJ<'
769
MEMBRANES
groups it is of minor importance. But when premature rupture of the membranes occurs in the lower economic groups, both white and non-white, it is a particularly lethal complication. This is undoubtedly related to the major obstetrical complications that accompany premature rupture of the membranes in these groups. Table X is concerned with death rates in the white and non-white patients according to the mother's age. It is evident that there should be an increase in the death rate in both the premature rupture group and the non-premature rupture group above 30 years of age. In the white population, this increase is of the same order of magnitude whether or not the membranes have ruptured prematurely. In the non-whites under 30 years of age, with infants over 2,000 grams, premature rupture of the membranes was not a serious complication. But the difference in death rates becomes striking in the non-white patients who are over 30 years of age and have premature rupture of membranes. It is in these cases, however, that we find the highest incidence of toxemia of pregnancy, premature separation of the placenta, intrapartum infection, and abnormal ptesentations. TAHLJo;
X.
llEA'rH HATES PER HUNDRED DELIVERIES BY RACE m' ALI, lNFA~TS ABOVE ~.00 (tRAMS ~WITH AND \VITHOUT PREMATURE RUPTURE 0~' THE MEMBRA:-Io~Fl ACCORDING TO MOTHER'S AGE
AGE
NO PREMATURE RUPTURE OF MEMBRANES
PREMATURE RUI'Tt'RE m• MEMBRA:-IEH
1.83 1.27 2.46
1.08 1.08 :l.6:!
1.88 2.01 3.i5
:l.B :l.R:l !Uti
[
Whit e.Less than 20 :!0-30 Above 30
r.·on-white.Lrss than
~0
:!0-30 Above clO
The southern part of the United States is fraught with many obstetrical problems. There are a large number of mothers who live under extremely poor socioeconomic conditions. These people have poor dietary habits and nutrition.!J Perhaps worse, formal education is lacking, and either they do not perceive the need of preventive medicine and prenatal care or they fail to use it when it is offered to them. In Table XI, the highest perinatal mortality rates both with and without premature rupture of the membranes occurred in the groups of mothers who had only elementary and grammar grade education. ·whether or not better education is the solution to this problem is unknown because it may be a relationship of association only. It is a hypothesis worth pursuing, never· theless. ~ 'I'ABL}:
XL
DEATH RATES PER HUNDRED DELIVERIES I~ ALL INFANTS ABOVE \VITH AND WITHOUT PREMATURE RUPTURE OF THE MEMBRANES ACCORDING TO YEARS OF MOTHER'S EDUCATION
2,100
:c~-~--~------==========~================~==========
YEARS OF' EDUCA'riON
Total l:l or more
!l-12 0-8
NO PREMATURE RUPTL'RE m' MEMBRANES
1.66 1.05 1.71
PREMATlTR~;
.~~~
RUPTllRE
OF MEMBRANES ~.B
0.63 2.44
GRAMS
770
FLOWER~
r:'l' AL
\ !! .
l
l lb~l ~\~~!it'\ ~)f'f(lht•r. jQ~~
lt is difficult to draw definite conclusions from these data. It is evident that premature rupture of the membranes occurs frequently among patients seen in medical centers of the type surveyed here. It is often associated with major obstetrical complications. It can within itself be a lethal complication especially for the infants of the older non-white mothers and is more prevalent in the lower socioeconomic groups. It adds great gravity to the major obstetrical complications that befall thest> mothers and often is the final blow that brings ileath to th('il" infants.
Summary A sample of cases of spontaneous premature rupture of the membranes associated with the delivery of approximate]~- 7.ii00 infants weighing 400 grams 11nd above is presented. The over-all incidence of p1·ematurc rupture of the membranes was 15.8 per cent. The incidence of premature rupture of the membranes among the fetal and neonatal deaths was 26.7 per cent. Premature rupture of the membranes occurred in association with a sizable number of major obstetrical complications. Infection was the principal lethal factor in the infant deaths which were primarily clue to premature rupture. It occurred more frequently among the non-white and less educated mothers, and was tolerated less well by the older mothers from lower socioeconomic groups, whether the classification was ba~ecl upon the mothN's education. raef', or the father's occupation. Premature rupture of the membranes i;;; a major obstetrieal eomplication which reqnirf's additional study.
References 1. Donnelly, J. 1!'., Flowers, C. E., Creadick, R.N., Greenberg, B. G., and Wells, H. B.: AM. J. 0BST. & GYNEC. 74: 1245, 1957. 2. Wells, H. B., Greenberg, B. G., and Donneliy, J. F.: North Carolina Fetal and Neonatal Study: I. Study Design, Some Preliminary Results, Am. J. Pub. Health. (To be published.) An. d. Inst. matern. y Asist. Social, RuetlOS Aires ~. Di Guglielmo, L., and Pepe, A. L.: 4: 50, 1942. 4. Embrey, M. D.: J. Obst. & Gynaec. Brit. Emp. 60: 37, 1953. 5. Kjessler, A.: Acta obst. et gynec. scandinav. 35: 495, 1956. 6. Cron, R. S., and Brown, R. C.: Obst. & Gynec. 1: 234, 1953. 7. Eastman, N. J.: Williams Obstetrics, ed. 11, New York, 1956, Appleton-Century-Crofts, Inc. 8. Calkins. L. A.: AM. J. 0BST. & GYNEC. 64: 871, 1954. 9. Smith, 'G. S., MacKinnon, C. F., and Malleson, A.: Bull. School Med., University of North Carolina 2: 15, 195--J..
Discussion DR. HERBERT M. BLACK, Columbia, S. C.-In Table IV, the authors show that apparently 50 per cent of the infants were possibly lost because of this complication. They feel that a latent period greater than 48 hours in cases of mature infants increases the mortality three times. There seems to be no such correlation in infants below 2,500 grams. It is of considerable interest that all the full·term infants who died of infection had latent periods greater than 36 hours. We might consider this the "critical hour." Errors in the obstetrical management of patients with premature rupture of the mem· branes (Table VII) occurred in 25 per cent of all cases. lt seems that this is a iittle high in three teaching institutions, if I interpret this correctly.
Volume 76 Number 4
SPON'l'ANEOUS
PREl\1A'l'Ul~E
HCP'l'lTHE or• MEMBRANES
771
The management of these patients should be along the following lines: (I) ho~pi tal ization; (2) sterile vaginal examination for correct diagnosis of ruptured membranes, prese11 tat ion, abnormalities, etc.; ( 3) sulfonamides (if the patient is not sensitive) until 48 hour~ following delivery; (4) instruction in the proper hygiene to prevent infection; (5) :nmitin:~ the spontaneous onset of labor if premature, medical induction, if at term; ( 61 discharge of the patient if the onset of labor does not occur within 72 hours, with a daily report of temp<>r ature and fetal movement; (7) cesarean ~ection only when othf'r inr than to searrh for something to do after the aeeident has oeeurred. DR. A. R. GARNETT, Norfolk, Va.-In the belief that there iR general indifft>r<'nr·<> to this problem and that the caliber of obstetrics praetiee fir·st. which has a three·year, Board-recognized training program, in the year 1955 the recorded in<'idence of premature membrane rupture was fount! to be 0.99 per cent in 2,451'1 rleliver-ie~: in 1956, O.i per ceut in 2,614 deliveries. In the second hospital, which also has a Broapt ol these e11_ses _; the nomenc.lature., prenu:tture rupturf! of the mern branes, waR not u~P•l. _:\ nd 'in tho third, a private hospital with no elinic patientg, a ~imilar situation was encountered. ,\u other point of interest, in the first hospital mentiont>d, approximately 20 physicians du ()P per cent of tht> work in the Obstetrical Department and every <'ase of reconle1l prr>n1ature ruptme came from the practice of 6 of these 20 phy~iciam·. In the recent literature there is a deflnite paucity of material on this sub jed; how<'~'""• what is available demonstrates incidence rates comparable to those rPporteil by 1lr. Flower~' group. The lack of general interest combined with a relatively high incidenee ins constitutes one m<>ang of irnpn•,ing fetal mortality rates. A simple regime might include the following li~tPd in order of their importanrf': , l · d i agnosia, (2) bed rest, (3) medications to dPrrease uterine irritability, <41 antibioti<·s, ,_-,, i11 duction, a.nd (6) Cesarean section. To enlarge hri<>fly on ead1: Diagnosis is usually quite obvious. \Yhen questionable, visualization of th(! r•r!rvix and vaginal vault, Nitrazine or litmus paper to c!Ptrrmine vaginal alkalinity, and, whPIJ t}ll''<' fail. Papanicolaou smears are quite helpful. Bed rPst is considered imperative, both to llelay the on~r't of uterine irritability and, b,v relativflly immobilizing the infaut, to dE>crease thr:> ehallg'f'~ in positiV<' and negative pn'~Hlll'•'·' \\·hirh c·.an take place after rupture of the membrane~. nnritw in fection. Medications to decrease uterine irritability r·an hel,Ollle an extn'Inely r·ontro\·ersial >'Ub ,1ect. When it is felt, however, that delay in delivery wilt move the involwd fr>tus from fl nonviahle into a viable category, it behooves u~ to eonsi mothE>r and/or pneumonitis in the infant until delivery takes place, and, finally, the jndieious <'hoi<·e of medical induction or cesarean section, depending upon the problem with which wo ar<' confronted, such as malpresentations, disproportion, or prolapsed em·d. IYill re$nlt in oht:Jining· viable infants with a good chance of survival. By adhering to one of the many variations of this program, it i~ helievnd that n ~ig-nif want nmnlwr of infnnt~ may he ,n]vagecl from n group tl"' in>liff<•rr·n1 bundling ,f ll'hi<·li i,
772
FLO\VERH E'r AL.
Am.
J.
Obst. & Gynec. October, 1958
now exemplified by the case of the girl who, between the fifth month and term, calls her physician, informing him that she is leaking water, and is told to take it easy until she starts having cramps and then to call back. DR. B. G. GREENBERG, Chapel Hill, N. 0 ..- I would like to comment a little about some of the methodological problems that are involved in a study of this kind. First of all, as Dr. Flowers indicated briefly, this type of study is what we call a retrospective study; that iR, we are sort of looking back over our shoulders at what happened after it happened. As such, a study of this kind is not designed to prove any causal relationships, for example, as to what causes premature rupturl' of the membranes or how to treat it. All we can hope to ilo in a study of this kind is to show very high associations between certain variables and use this information to suggest certain worthwhile leads, worthwhile in the sense of further investigation. The data upon \Yhich these results have been obtained are rather preliminary. They were collected during the first 2 years of the study. Since that time we have collected 2 years of additional clata, and we have also extended the study to two additional hospitals in the city of Charlotte. 'Ve do not know actually when the membranes rupture in every case. Furthermore, we do not know when thr onset of labor aetually o~curred. As it is, it is usually an arbitrary definition in terms of eervical effacement. The point which we would like to consider here is the methodological point that Dr. Garnett mentioned with regard to his inVPstigation of this condition in his own city. He found premature rupture of the membranes in less than 1 pPr cent of the cases. My guess is that the obstetricians recorded premature rupture of the membranes only when it resulted ix1 an ov<>rlong latent period. Consequently, it is very important in a study of this kind that we give consideration to the methodology. Here, in choosing a comparison group, it is important that we use the same consideration as to who goes into this study, and that we have no influence in choosing who goes into the comparison group. The comparison group is chosen after the child is born so that none of the entries in the mother's file were influenced by previous knowledge that the child was going to be a comparison one. Su('h knowledge might influence the decision as to whether to write down "premature rupture of the membranes" or "non-premature rupture of the membranes.'' We think that is important in any control study-that the control or comparison group be chosen at the same time, in the same place, in the same manner, and treated by the same personnel, and not consist simply of a historical review of cases of 5 or 10 years ago. DR. FLOWERS (Closing).-Dr. Black has pointed out that we felt there was an error in management in approximately 25 per cent of the fetal and neonatal deaths with premature rupture of the membranes. \Ve have attempted to make a critical study of our perinatal mortality; possibly we have been hypercritical, but we are attempting to improve our perinatal mortality. Dr. Greenberg has commented that this study was not designed to determine the proper obstetrical management of patients with premature rupture of the membranes. But the management of this complication is of primary importance, and I am grateful for the timely remarks of our discussants.
E.
FLoWERs, JR., M.D., CHAPEL HILL, JAMEs F. DoNNELLY,
~I.D., \'\TrNsToN-SALEM, RoBERT t~. CREADRICK, ~v1.D., DuRHAivi,
BERNARD G. GREENBERG, PH.D., AND H. BRADLEY WELLS, M.S.P.H., CHAPEL HILL,
N.c.
(From the Departments of Obstetrics and Gynecology of the University of North Carolina School of Medicine, Chapel Hill,- Duke University School of Medicine, Durham,- Bowman Gray School of Medicine, Winston-Salem, and the School of Public Health of the University of North Carolina)
1 AST year there was presented to this Association the first report of the coL operative Perinatal Mortality Study which is being conducted by the Ikpartments of Obstetrics and Gynecology of the University of North Carolina. Duke University, Bowman Gray School of Medicine, the School of Publie Health of the University of North Carolina, and the North Carolina Statf• Board of Health. This paper 1 emphasized the primary importance of sociocconomie factors in perinatal mortality and indicated that a sizable number of perinatal deaths were associated with spontaneous premature rupture of the membranes. A further study of this problem was thus stimul11tecl.
Method of Study The data for this study were obtained from the three cooperating medical schools and are based upon 7,511 deliveries of infants weighing 400 grams and above, which occurred between 1954 and 1956. 'fhe tabulations are taken from 763 study schedules based upon interviews and hospital records of single births with known birth weight and known latent period in the cases of spontaneous premature rupture of the membranes before the onset of clinical labor. In each tabulation of a given item, the unknowns have been excluded from the total. The study schedule is a 6 page booklet plus a supplement for recording autopsy findings. Information for the schedule is obtained from the hospital reeords and by direct interview with the mother. A study schedule is prepared for all fetal and neonatal deaths occurring in the three University hospitals. A comparison study schedule is also completed for approximately every fifteenth infant who survives the neonatal period. The comparison group is selected in such a manner that the obstetrician is not aware of which infants will serve as controls until after delivery. Perinatal mortality in this study refers to all deaths of infants weighing 400 grams or more through the twenty-eighth da.'T of life. The statistical methods employed in the study have been reported by \Vells, Greenberg, and Donnelly. 2 •Supported in Part by a grant from The Children's Bureau. Appreciation is expressed to Dr. A. H. Elliot of the North Carolina State Board of Health for his assistance in this study and his administration of the grant. tPresented at the Twentieth Annual Meeting of the South Atlantic Association of Obst"tricians and Gynecologists, Hollywood, Florida, Feb. 1 to 5, 1958.
761
!•'LOWER~
762
ET A L.
\rn. /. t )b"t ~ ()._ 0\..'t
Incidence The reported incidence of premature rupture of the membranes varies widely according to geographic locations. Di Guglielmo and Pepe'1 reported an incidence of 5 per cent in Argentina, while Embrey 4 reported 13.9 per cent in England and Kjessler 5 18.9 per cent in nothenburg, Sweden. In the United States, Cron and Brown'5 have reported an incidence of premature rupture of the membranes of 9 per cent while Eastman 7 has reported 12 per cent and Calkins8 14 per cent. GENERAL DATA AND INCIDENCE OF PREMATURE RUPTURE OF MEMBRANES NORTH CAROLINA PERINATAL MORTALITY STUDY 1954-1956 All Deliveries
II All single bnths 1 koo•n latent oeriod. birth weiaht. and rupture ·at meinbranes ~ ·
~All.
I 'w•• I deh11et1es
Over 2000
Over 2000 grams
Non-premature
Non-premature
32.9%
15.8% Premature
rupture of
membranes
Premature rupture of membtones
Non-premature rupture
Non-premature rupture
rupture
ropture
grams
23
IB 7%
Premature rupture of membranes
Non~premoture
rupture
74
15.4%
Premature
Premature
membranes
membranes
rupture of
rupture of
Fig. 1.
Fig. 1 depicts the incidence and importance of premature rupture of membranes in this study. The over-all incidence among the deliveries in the three medical schools was 15.8 per cent. However, 75, or 26.7 per cent of all the fetal and neonatal deaths, were associated with premature rupture of the membranes. This complication occurred in a~sociation with the birth of 32.9 per cent of the infants who weighed 400 to 2,000 grams and 18.7 per cent of those who weighed 2,001 grams and above.
Concurrent Obstetrical Complications A study of the 52 deaths of infants weighing 400 to 2,000 grams and the 23 deaths of those weighing 2,001 grams and above with premature rupture of the membranes disclosed a sizable number of other major obstetrical complications (Table I). These obstetrical complications assume added significance when they are converted into percentages of occurrence. Of the 75 fetal and neonatal deaths,
\'olume 7f• \.umber -t-
SPON'l'ANEOUS PREMATURE
RUPTFRJ<~
OF MEMBRANES
there were 2.t-, or 82 per cent, complicated by infection. There were 20 mothers, or 26.7 per cent, in the same group who had premature separation of the plaeenta, 111pture of thP marginal sinus, or other significant antepartum bleeding. Approximately one half of these hemorrhagic complications, however, occurrpd in mothers whose infants weighed 400 to 1,000 grams. Eighteen, or 24 per <•enL of all eases of fetal and neonatal death with premature rupture of the membrane:-: were complicated by toxemia of pregnancy. The umbilical cord prolapsed. in 16, or 2l.B per cent of all the cases, hut this eomplication was responsible for the death of the infant in only 10.7 per cent of these 16 cases. Intrauterine •lea11t had occurred in the other cases prior to prolapse of the cord. 'l'ABLF:
L
MAJOR OBSTETRICAL CoMPLlCATIOKS AssociAT~:p
\\'JTll
Pru;MNrrnE RPJ"rna: ot·
~'liE ~!EMHBAKES
1Nr'A:NTH
COMPLICATIO:N
-:---:-:-:
Antepartum or intrapartum fever above 99° F. Premature separation of the placenta, rupture of the marginal sinus, or other signifirant antepartum bleeding oeeurring before premature rupture of the membranes Premature separation of the placenta, rupture of the marginal sinus, or other significant antepartum bleeding ON'UITing after premature rupture of the membranes 'l'oxemia of pregnancy Prolapse of the umbilical cord Congenital anomalies incompatible with life Idiopathic fptal death in utero preceding rupture of the nu•m branes Uirrumvallah· pla<·<~nta Diabetes Polvhvdramnios Ute'ritie inertia Abnormal pr··~entations Breee.l1 Face or Brow TransvPrse Lie ------~~~--~---------------Total fptal and nPonatal deaths in cases of premature rupture of nH'mhraneR Th<' total
i~ le~~
than the
~urn
1
.fll0-:!,001) mL\MF: JS
Jl\"r'AK1'N
1 :!,000 CHC\:11:'1 _j__,\_~l___-~!~1\'f~ ti
..
1~
II
;}
II 11
,)
:l
.)
~
l II
il II ~0
,,
Hi
in eaeh column because of multiple complications
Abnormal presentations were associated with 27, or 36 per cent, of the 1otal deaths in cases of premature rupture of the membranes. This complication was also assoriated with other lethal obstetrical conditions and contributed to a death rate of 81.82 per 100 deliveries of infants weighing 2,001 grams and above. This is shown in 'l'able II where it is seen that the death rate in a similar weight gToup with obstetrical ('omplications was onl~' 4.26 prr 100 deliveries when the tnrmhrarws had not ruptured prematurel:v. TAB!,"
li.
l>F.A1'H RATE t'ER
DELIVERIES OF lNFAKTS \\·r,H;HISG :!,00] GHAMS AXIl .\J!fiVf; ACCORDING TO PRESENTM'IOX .
]00
KO PREMATURE Rl'PT\'RE OF MEM!lRANJ<;S
Tot!!] VPrtt'x AU others
1.74 1.5R 4.26
l'R~:MATTJHE
Rl'PTU!tF: OF MEMBRANES
:n.R:!
------------------------
DPath rat!'~ in this anu all other tables are romputed by thP following equation: ERtimated pPrinatal mortality rate per 100 delivPries = Numher of fetal and neonatal deaths x 100 NumbPr of fetal and neonatal deaths -+ Pstimaterl numhPr of s'urvivorR-
-\m .. L (Jbo.t. & (hnec October, 195R
PLOWERR ET AL.
764
Role of Premature Rupture of the Membranes in Perinatal Mortality Since there was a high incidence of obstetrical complications associated with premature rupture of the membranes, eaeh case was studied to determine whether rupture of the men1branes vvas the Jnatior or initiating cause of death. TABLE
Ill.
CASES IN \VHICH PREMATURE RUPTURE OF THE MEMBRANES WAS NOT 'fHE MAJOR OR INITIATING :~<'ACTOR IN PERINATAL DEATH
CAUSE
0~'
HEATH
Premature separation of the placenta, rupture of the marginal sinus, or significant antepartum bleeding occurring before rupture of the membranes Congenital anomalies incompatible with life Idiopathic fetal death in utero occurring before premature rupture of the membranes Intrauterine anoxia associated with severe toxemia of preg-
IN~'ANTS
INFANTS
400-2,000
~.001 flRAMS
GRAMS
AND ABOVE
12 3
3 5
~
3
2
0
il 2
2
0
52
23
spontaneously
fetal and neonatal deaths in cases of premature rupture of membranes
It is evident from Table III that premature rupture of the membranes was not a major factor in the death of 21, or 40.4 per cent, of the infants weighing 400 to 2,000 grams and in 16, or 69.6 per cent, of the infants weighing 2,001 grams and above. Premature rupture of the membranes was merely an incidental occurrence. The infants actually succumbed to other lethal obstetrical complications such as premature separation of the placenta, toxemia of pregnancy, maternal diabetes, heart disease, congenital anomalies incompatible with life, and to idiopathic fetal death in utero occurring before rupture of the membranes. TABLE IV.
CASES IN WHICH PREMATURE RUPTURE OF THE MEMBRANES WAS THE POSSIBLE MAJOR OR INITIATING FACTOR IN PERINATAL MORTALITY
CAUSE OJ<' DEATH
Neonatal deaths associated with amnionitis, atelectasis, and/ or hyaline membranes Intrauterine deaths associated with amnionitis and/or intrauterine pneumonia Prolapse of the umbilical cord (primary cause of death) Premature separation of the pla('enta after premature rupture of the membranes Intracranial hemorrhage (labor initiated by premature rup· ture o:f the membranes) Total Total fetal and neonatal deaths in cases of premature rupture of membranes
INFANTS
INFANTS
400-2,000
2,001 GRAMS
GRAMS
ANP ABOVE
11
1
7 6
4 2
5
0
2 31
0 7
5~
23
A review of the 75 deaths also showed that 31, or 59.6 per cent, of the infants weighing 400 to 2,000 grams, and 7, or 30.4 per cent, of the infants weighing 2,001 grams and above were possibly lost as a result of premature rupture of the membranes.
Volume 7G
!'JumbN 4
SPONTANEOUS PREMATURE RUPTURE OF MEMBRANES
Intrauterine Infection, Latent Period, and the Duration of Labor Intrauterine infection was the major cause of death in the cases in whirh the pet·inatal mortality was relate~ to pre.matur~ ruptur~ of ~he m~mbranes. The 1nembranes are an effective barr1er to 1ntrauter1ne 1nfect1on; but \Vhrn mpture occurs, bacteria invade the amniotic sac in a matter of hours. Once severe amnionitis is present, it may cause the demise of the infant from intrauterine pneumonia or contribute to pneumonia and atelectasis in the neonatal period. Moreover, the association of premature rupture of the membranes, fever, intrauterine anoxia, or other major obstetrical complications will in(•reasc thf' amount of aspiration of the amniotic contents and increase the likelihood nf pulmonary infection. Amnionitis and intrapartum infection contributed to 23, or 30.7 per eenL of the 75 deaths associated with premature rupture of the membranes. It <'allnot h<' stated that amnionitis or intrapartum infection was the real cause of death nf thr infants weighing less than 2,000 grams; prematurity alone could han been the lethal factor. But premature rupture of the membranes and a prolonged latent period were undoubtedly major fMtors in the 5 deaths of tlw largrr infant~':. Guilbeau and Eastman 7 have carefully evaluated the effert of the lah•n\ period on pe1·inatal mortalit;v in eases of p~emature rupture of the memhranPs. Tlw,v havP concluded that the duration of the latent period is not a signiflean1 factor in infants below 2,499 grams be(•ause of the major significanee of pl'('" maturity. In mature infants, howen~r, a latent period of 48 hours and gTratPr is assoriatecl with a threefold increase in perinatal mortality. The nnmber of cases in this series is small compared to that of GnillH~au and Eastman, but there is a elose correlation in the findings. Table V l'jhO\VS the percentage of infants vvith -rarions late.ilt periofls a(•(•nr1l ing to weight. TABLE V.
LATENT PERIOll 1:-i CAS~;s OF PRF:MA'l'l'RF; Rla"l'UR~; 0~' 'rHE JHE~1BRA.Nlcfl
BIRTH WEIGHT
____(g_!t~~
Perinatal Deaths.400-2,000 2,001 and above
TOTAL
0-11 HOURS
--'~~-N_O_.~----'--~---'(% L_ 52 23
I l!.l<~i) l
HOURS
((!£)_ ___
lOVER
35 Il~Yl'l~~;
L __ ~ \
15.4
l7.il
52.~
~n.1
:.:!-1 .7
7il.O
:20.:1
li.i
67.:-t
Survivors (Controls).400-2,000 and above
0 74
Only 32.7 per cent of the mothers who were delivered of infants in the lower weight group had a latent period of less than 35 hours. The average latent period in the cases in which the infant died in this weight group was 9 days. Essentially 90 per cent of the 97 infants with premature rupture of the membranes who weighed 2,001 grams and above had latent periods of 35 hours and 1ess. The latent period was longer than 36 hours in all cases of infants in this weight group with premature rupture of the membranes who died of amnionitis or intrapartum infection; in fact, 2 had latent periods of 38 honrR, one of 6 days, one of 7 days, and one of 9 days. In the weight group over 2,000 grams, the mothers of surviving infants had, on the aYerage, a shorter latent period than the mothers of infants who di
FLOWERS ET AL.
766
Am. /. ()h:q, &. Grnec.
October. 1958
Table VI gives a computation of the mean hours of labor in cases of fetal and neonatal death and of surviving infants with or without spontaneous premature rnpture of the membranes. TABLE Vl. MEAN HOURS OF LABOR IN CASES OF FETAL Al'\D NEONATAL DEATH AND SuRVIVI.:-!G INFANTS WITH AND .WITHOUT SPONTANEOUS PREMATURE RUPTURE OF MEMBRANES NO PREMATURF. RUPTURE OF MEMBRANES
Fetal and neonatal deaths 400 to 2,000 grams 2,001 grams and above Surviving infants 2,001 grams and above
-----'-
PREMATURE RUPTURE OF MEMBRANES
9.1
8.6
10.7
16.8
8.9
7.4
In the cases of surviving infants who weigh 2,001 grams and above there actually appears to be a reduction in the mean duration of labor with premature rupture of the membranes. But the mean duration of labor is increased for all infants in this weight group who died, and is almost doubled with premature ruptu.re of the membranes4 Thus premature rupture of the membranes has a favorable effect on the duration of labor only in surviving infants. Prolapse of the Umbilical Cord
Of the 75 deaths studied in Table IV there were 8 deaths, or 10.7 per cent, which were possibly the result of prolapse of the umbilical cord in association with premature rupture of the membranes. All of these infants had some abnormality of presentation, either footling' breech, transverse lie, or floating vertex. These deaths n1ight have occurred if the men1branes had rl1ptured dnring labors not complicated by premature rupture of the membranes but whether or not in this magnitude is not known. The data concerning prolapse of the cord are included for completeness. It is difficult, with the paucity of data, to determine its absolute significance in the problem of spontaneous premature rupture of membranes. Errors in the Management of Cases of Premature Rupture of the Membranes It is possible to criticize the obstetrical management of some cases in any series of perinatal deaths, particularly when the deaths are associated with a number of major obstetrical complications. This series is no exception. There were 18, or 24 per cent, in which there were thought to be errors in obstetrical management (Table VII). Only 8, or 10.7 per cent, of these cases were unquestionably associated with the problem of premature rupture of the membranes. Delivery of the breech was poorly and 11nskillfully managed in the case of one infant weighing 1,600 grams and of another infant weighing 3,800 grams. Cesarean section would have been preferable to version and extraction in the case of a 2,700 gram infant with a latent period of 36 hours and a transverse lie. There were 3 cases of maternal diabetes the management of which are open to criticism. One infant weighing 1,700 grams died as a result of totally inadequate care by the referring physician. Two other mothers with breech presentations of infants weighing 2,800 and 3,800 grams should probably have been delivered by cesarean section at 38 weeks. Two immature infants were lost as a result of the mismanagement of severe maternal rheumatic heart disease with failure. One case of uterine inertia was poorly managed during labor and delivery. One patient with intermittent fetal distress was observed for 2 hours before a sterile vaginal examination disclosed the cervix to he 4 em. dilated and the cord prolapsed.
\.(dume 76 \jnmher 4
TABLE VJI.
KPONTANEOUS PREMATURE RUP'fURE OF MEMBRANES
7fli
ERRORS IN THE OBSTETRICAL lVIANAGEMEN'l' 0.' CASES \VITH PREMA'l'f)RE Hl'P'I'Illif: O~· MEMBRANES lN~'Al'\TS
400-~,000
mtA::IiS
ERRORS IN MANAGEMENT
improper rnanagerrwnt of abnormal presentation~: Breech Transverse lie Improper treatment of maternal diabetes Improper treatment of rheumatic heart disease rmproper management of uterine inertia [mproper management of prolapse of the umbilical eon! Failure to treat intrapartum infection with antibiotir•s an•l
0
1 II
n
1
l
0
.j
]II
The Treatment of Infection Twenty-four, or 32.0 per cent, of the mothers of the 75 infants who died after premature rupture of the membranes had antepartum or intrapartum infection. Fourteen of these 24 infants with infection were alive at the onset of labor and 8 of them were not treated with antibiotics and/or oxygen during labor. Guilbeau and Eastman' have presented condusive data that the administration of penicillin during the latent period has no effect on perinatal mortality. It appears that the use of the wide-spectrum antibiotics would also be ineffective "1 • •, uurmg me wno1e latent penoa; tney may oe contrammcatea smce tne oatance of the bacterial flora would be affected. The use of wide-spectrum antibiotics, however, becomes mandatory after the onset of infection during the latent period and during labor and the puerperium. It also seems reasonable to administer 40 per cent oxygen to mothers who have an elevation in temperature of 100° F. or more during labor. An elevation in temperature increases the metabolic need of the infant for oxygen and its administration to the mother will increase the partial pressure of the circulating oxygen and improve its passage across the placenta. The parenteral administration of tetracycline or chloramphenicol and the use of oxygen may not have prevented these 8 deaths. It is felt, however, that there are good theoretical grounds for the use of both agents and that the,\· should have been used. ~-
1
~
...
•
•
•
.,.
•
..
•
•
., •
•
...
..
• ...
't
..,
Socioeconomic Factors
PreYious review of the material in the North Carolina perinatal mortalit~· study revealed that socice{lonornic factors '\Vere. probably of major in1portance in the causation of fetal and neonatal deaths. Since premature rupture of the membranes is so intimately associated with the problems of prematurity and obstetrical complications, an analysis of the data was made for parental and en \'ironmental factors. Table VIII is a study of the percentage distribution of cases of infants weighing from 400 to 2,000 grams according to race, father's occupation, and mother's education. It was impossible to compute death rates according to these factors since there were insufficient controls in this weight group. Death rates would have had little meaning since prematurity is of ri1ajoi· importance in this class of infants.
FLOWERS BT AL.
768 T.\BLB
Am.]. OG:::.t. & Cynec. October, ]91;"8
SocioEcoNOMIC FAc·roRs IN .F'ETAL-NEONATAL D~~ATHS m' 400-2,000 VIII. INFANTS WITH AND WITHOUT PREMATURE RUPTURE OF THE MEMBRANES ACCORDING TO PERCE~TAGE DISTRIBFTION m' CASES NO PREMA'fURE RUPTURE OF MEMBRANES
PREMATURE RlfPTURE
GrtAM
m'
MF:MBRA~E;S
Race.Total White Non-white
100.0 67.3 32.7
100.0 50.9 49.1
100.0 21.] 37.9 41.1
100.0 19.1 31.9 48.9
100.0 213.6 55.6 20.8
100.0 13.8 44.8
Father's Occupation.Total Group 1 Group II Group III
Mother's Education.Total 13 or more years 9-12 years or less 8
Premature rupture of the membranes in the smaller weight groups occurred more frequently in the non-white race. This is evident in the analysis for race and for mother's education because the majority of patients who had 0 to 8 years of schooling were non-white. The father's occupation was classified in three groups. Group I consists of professional people, managers, officials, proprietors, and students in the Universities. Group II consists of clerks, sales workers, craftsmen, foremen, and operators. Group III includes farmers, farm laborers, other laborers, and household workers. It is clearly evident that the largest portions of the fetal and neonatal deaths of these small infants, with and without premature rupture of membranes, occurred in the lowest socioeconomic group. But the difference between occurrence and nonoccurrence of premature rupture of the membranes was so slight that it is difficult to say that the event itself is related to the father's occupation. There were sufficient control infants weighing 2,000 grams and above to allow calculation of death rates for various socioeconomic factors in these cases. TABLE TX.
__
DEATH RATES PER HUNDRED DELIVERIES BY RACE OF ALL INFANTS ABOVE GRAMS \VITH AND WITHOUT PREMATURE RUPTURE OF THE MEMBRANES AccoRDING TO FATHER's OccuPATION
2,001
_:._OC::._:C~U:._:P:._:A:__T_IO_N___:G_:__R_O_UP_ _ __,_____N_O_P(_~;_M_:::_:_,~_:_~_\.~~~TU~--l- . PR~~A:~~B:z::~RE White.I
1.17
II
1.99
Ill
1.6]
1.08 0.76 6.17
1.02 2.84
11.29
Non-white.! II
III
2.13
Table IX presents interesting data concerning the relationship of the father's occupation to premature rupture of the membranes. When this complication occurs with infants over 2,000 grams of mothers in the upper economic
Volume 76 Number 4
SPONTANEOUS PREMATURE R.UPTURE
OJ<'
769
MEMBRANES
groups it is of minor importance. But when premature rupture of the membranes occurs in the lower economic groups, both white and non-white, it is a particularly lethal complication. This is undoubtedly related to the major obstetrical complications that accompany premature rupture of the membranes in these groups. Table X is concerned with death rates in the white and non-white patients according to the mother's age. It is evident that there should be an increase in the death rate in both the premature rupture group and the non-premature rupture group above 30 years of age. In the white population, this increase is of the same order of magnitude whether or not the membranes have ruptured prematurely. In the non-whites under 30 years of age, with infants over 2,000 grams, premature rupture of the membranes was not a serious complication. But the difference in death rates becomes striking in the non-white patients who are over 30 years of age and have premature rupture of membranes. It is in these cases, however, that we find the highest incidence of toxemia of pregnancy, premature separation of the placenta, intrapartum infection, and abnormal ptesentations. TAHLJo;
X.
llEA'rH HATES PER HUNDRED DELIVERIES BY RACE m' ALI, lNFA~TS ABOVE ~.00 (tRAMS ~WITH AND \VITHOUT PREMATURE RUPTURE 0~' THE MEMBRA:-Io~Fl ACCORDING TO MOTHER'S AGE
AGE
NO PREMATURE RUPTURE OF MEMBRANES
PREMATURE RUI'Tt'RE m• MEMBRA:-IEH
1.83 1.27 2.46
1.08 1.08 :l.6:!
1.88 2.01 3.i5
:l.B :l.R:l !Uti
[
Whit e.Less than 20 :!0-30 Above 30
r.·on-white.Lrss than
~0
:!0-30 Above clO
The southern part of the United States is fraught with many obstetrical problems. There are a large number of mothers who live under extremely poor socioeconomic conditions. These people have poor dietary habits and nutrition.!J Perhaps worse, formal education is lacking, and either they do not perceive the need of preventive medicine and prenatal care or they fail to use it when it is offered to them. In Table XI, the highest perinatal mortality rates both with and without premature rupture of the membranes occurred in the groups of mothers who had only elementary and grammar grade education. ·whether or not better education is the solution to this problem is unknown because it may be a relationship of association only. It is a hypothesis worth pursuing, never· theless. ~ 'I'ABL}:
XL
DEATH RATES PER HUNDRED DELIVERIES I~ ALL INFANTS ABOVE \VITH AND WITHOUT PREMATURE RUPTURE OF THE MEMBRANES ACCORDING TO YEARS OF MOTHER'S EDUCATION
2,100
:c~-~--~------==========~================~==========
YEARS OF' EDUCA'riON
Total l:l or more
!l-12 0-8
NO PREMATURE RUPTL'RE m' MEMBRANES
1.66 1.05 1.71
PREMATlTR~;
.~~~
RUPTllRE
OF MEMBRANES ~.B
0.63 2.44
GRAMS
770
FLOWER~
r:'l' AL
\ !! .
l
l lb~l ~\~~!it'\ ~)f'f(lht•r. jQ~~
lt is difficult to draw definite conclusions from these data. It is evident that premature rupture of the membranes occurs frequently among patients seen in medical centers of the type surveyed here. It is often associated with major obstetrical complications. It can within itself be a lethal complication especially for the infants of the older non-white mothers and is more prevalent in the lower socioeconomic groups. It adds great gravity to the major obstetrical complications that befall thest> mothers and often is the final blow that brings ileath to th('il" infants.
Summary A sample of cases of spontaneous premature rupture of the membranes associated with the delivery of approximate]~- 7.ii00 infants weighing 400 grams 11nd above is presented. The over-all incidence of p1·ematurc rupture of the membranes was 15.8 per cent. The incidence of premature rupture of the membranes among the fetal and neonatal deaths was 26.7 per cent. Premature rupture of the membranes occurred in association with a sizable number of major obstetrical complications. Infection was the principal lethal factor in the infant deaths which were primarily clue to premature rupture. It occurred more frequently among the non-white and less educated mothers, and was tolerated less well by the older mothers from lower socioeconomic groups, whether the classification was ba~ecl upon the mothN's education. raef', or the father's occupation. Premature rupture of the membranes i;;; a major obstetrieal eomplication which reqnirf's additional study.
References 1. Donnelly, J. 1!'., Flowers, C. E., Creadick, R.N., Greenberg, B. G., and Wells, H. B.: AM. J. 0BST. & GYNEC. 74: 1245, 1957. 2. Wells, H. B., Greenberg, B. G., and Donneliy, J. F.: North Carolina Fetal and Neonatal Study: I. Study Design, Some Preliminary Results, Am. J. Pub. Health. (To be published.) An. d. Inst. matern. y Asist. Social, RuetlOS Aires ~. Di Guglielmo, L., and Pepe, A. L.: 4: 50, 1942. 4. Embrey, M. D.: J. Obst. & Gynaec. Brit. Emp. 60: 37, 1953. 5. Kjessler, A.: Acta obst. et gynec. scandinav. 35: 495, 1956. 6. Cron, R. S., and Brown, R. C.: Obst. & Gynec. 1: 234, 1953. 7. Eastman, N. J.: Williams Obstetrics, ed. 11, New York, 1956, Appleton-Century-Crofts, Inc. 8. Calkins. L. A.: AM. J. 0BST. & GYNEC. 64: 871, 1954. 9. Smith, 'G. S., MacKinnon, C. F., and Malleson, A.: Bull. School Med., University of North Carolina 2: 15, 195--J..
Discussion DR. HERBERT M. BLACK, Columbia, S. C.-In Table IV, the authors show that apparently 50 per cent of the infants were possibly lost because of this complication. They feel that a latent period greater than 48 hours in cases of mature infants increases the mortality three times. There seems to be no such correlation in infants below 2,500 grams. It is of considerable interest that all the full·term infants who died of infection had latent periods greater than 36 hours. We might consider this the "critical hour." Errors in the obstetrical management of patients with premature rupture of the mem· branes (Table VII) occurred in 25 per cent of all cases. lt seems that this is a iittle high in three teaching institutions, if I interpret this correctly.
Volume 76 Number 4
SPON'l'ANEOUS
PREl\1A'l'Ul~E
HCP'l'lTHE or• MEMBRANES
771
The management of these patients should be along the following lines: (I) ho~pi tal ization; (2) sterile vaginal examination for correct diagnosis of ruptured membranes, prese11 tat ion, abnormalities, etc.; ( 3) sulfonamides (if the patient is not sensitive) until 48 hour~ following delivery; (4) instruction in the proper hygiene to prevent infection; (5) :nmitin:~ the spontaneous onset of labor if premature, medical induction, if at term; ( 61 discharge of the patient if the onset of labor does not occur within 72 hours, with a daily report of temp<>r ature and fetal movement; (7) cesarean ~ection only when othf'r in
772
FLO\VERH E'r AL.
Am.
J.
Obst. & Gynec. October, 1958
now exemplified by the case of the girl who, between the fifth month and term, calls her physician, informing him that she is leaking water, and is told to take it easy until she starts having cramps and then to call back. DR. B. G. GREENBERG, Chapel Hill, N. 0 ..- I would like to comment a little about some of the methodological problems that are involved in a study of this kind. First of all, as Dr. Flowers indicated briefly, this type of study is what we call a retrospective study; that iR, we are sort of looking back over our shoulders at what happened after it happened. As such, a study of this kind is not designed to prove any causal relationships, for example, as to what causes premature rupturl' of the membranes or how to treat it. All we can hope to ilo in a study of this kind is to show very high associations between certain variables and use this information to suggest certain worthwhile leads, worthwhile in the sense of further investigation. The data upon \Yhich these results have been obtained are rather preliminary. They were collected during the first 2 years of the study. Since that time we have collected 2 years of additional clata, and we have also extended the study to two additional hospitals in the city of Charlotte. 'Ve do not know actually when the membranes rupture in every case. Furthermore, we do not know when thr onset of labor aetually o~curred. As it is, it is usually an arbitrary definition in terms of eervical effacement. The point which we would like to consider here is the methodological point that Dr. Garnett mentioned with regard to his inVPstigation of this condition in his own city. He found premature rupture of the membranes in less than 1 pPr cent of the cases. My guess is that the obstetricians recorded premature rupture of the membranes only when it resulted ix1 an ov<>rlong latent period. Consequently, it is very important in a study of this kind that we give consideration to the methodology. Here, in choosing a comparison group, it is important that we use the same consideration as to who goes into this study, and that we have no influence in choosing who goes into the comparison group. The comparison group is chosen after the child is born so that none of the entries in the mother's file were influenced by previous knowledge that the child was going to be a comparison one. Su('h knowledge might influence the decision as to whether to write down "premature rupture of the membranes" or "non-premature rupture of the membranes.'' We think that is important in any control study-that the control or comparison group be chosen at the same time, in the same place, in the same manner, and treated by the same personnel, and not consist simply of a historical review of cases of 5 or 10 years ago. DR. FLOWERS (Closing).-Dr. Black has pointed out that we felt there was an error in management in approximately 25 per cent of the fetal and neonatal deaths with premature rupture of the membranes. \Ve have attempted to make a critical study of our perinatal mortality; possibly we have been hypercritical, but we are attempting to improve our perinatal mortality. Dr. Greenberg has commented that this study was not designed to determine the proper obstetrical management of patients with premature rupture of the membranes. But the management of this complication is of primary importance, and I am grateful for the timely remarks of our discussants.