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Hypercoagulability in the dysmature syndrome
tlolume
111 .December
American
Journal
number
7
1, 1971
of Obstetrics and Gynecology
OBSTETRICS
Hypercoagulability in the dysmature syndrome FREDRIC JAMES DUNCAN
D. L.
FRIGOLETTO,
TULLIS, E.
JOHN
HINMAN,
Boston,
Massachusetts
M.D. M.D.
REID,
M.D. M.D.
A discordance between gestational age and fetal weight has been recognized clinically since the turn of the century. The failure to maintain a normal growth rate in utero is referred to as the “dysmature syndrome” or intrauterine growth retardation. Several etiologies, notably hypertensive pregnancy and renal disease, have been assigned to this syndrome, but in many of the cases there has been no demonstrable associated cause. It is proposed that an aberration of the clotting mechanism may play a role in some cases of intrauterine growth retardation. Cases are presented where a subclinical state of hypercoagulability has been encountered in the presence of intrauterine growth retardation, as measured by the presence of fibrin monomers, platelet function, and other factors related to the preconsumptive phase of the clotting mechanism.
SINCE THE writings of Ballantyne even before, those responsible for the From the Department Gynecology and the Medicine, Harvard England Deaconess Boston Hospital for
and care
of the parturient and her infant have wondered whether the characteristic appearance of the postmature infant, notably the absence of vernix caseosa and the discoloration and desquamation of the skin, had any significance. Clifford5 in 1954 challenged, as had others, the commonly held belief that the postmature infant was of excessive size due to the continuous growth; he contended that the reverse occurred and described and classified in some detail the appearance of these newborn infants and coined the term placental dysfunction to account for the observed changes in the skin and the wasting
of Obstetrics and Department of Medical School, New Hospital, and the Women.
The funds for this study were made possible by National Institutes of Health Grant No. 2-PO-I-HE-06302-10 to the Blood Research Institute, and Institutional Grant No. FRO5481-08 to the Boston Hospital for Women. Presented by Duncan E. Reid, M.D., on May 19, 1971, at the Nineteenth British Congress of Obstetrics and Gynaecology, Dublin, Ireland. 867
868
Frigoletto
et al.
of thr subcutaneous tissue. It was further concluded that the placental dysfunction syndrome can occur at any gestational age. Moreover, it is no\v recognized that failure to grow in utero may become a clinical problem from the twenty-sixth, twenty-eighth, and thirtieth weeks onward and in fact the fetus may be suffering from the effects of malnutrition even prior to this period. Now more commonly referred to as intrauterine growth retardation (IUGR) , the condition by definition is present when the neonate’s weight falls below the tenth percentile in accordance with the Denver intrauterine weight curve for infants of that particular gestational age.l’ Although the survival rate of the growth-retarded infant may be higher than an infant of comparable weight not so afflicted (the latter presumably of less gestational age), the ultimate development of these malnourished infants has been of increasing concern.‘, (i. i;. IS Indeed, there is a growing body of evidence to suggest that a major source of central nervous system damage of the newborn infant may reside in the fetuses that have experienced some degree of intrauterine malnutrition. Certainly lack of proper nutrition in the newborn period can adversely influence the brain, hence mental as well as physical development.“’ Whether the central nervous system deficiencies of these fetuses can be corrected after birth is a matter of controversy and debate. Beginning with Nelligan’s observation of a hypoglycemic state and confirmed by Cornblith and others, measurable metabolic alterations are present at birth in these infants.” This raises the proposition that if the fetus is to escape irreversible damage from intrauterine malnutrition the latter niust be recognized at the earliest moment and if possible corrected in utero. IUGR has been attributed to a host of causes, including rarely viral diseases and chromosomal disorders.‘. Ii Actually, the failure to grow in utero is encountered most frequently in a variety of obstetric states from deviations in placentation to renal disease and hypertension. but in some instances
the syndrornfb
occur:,
IL lthout
:trly appareilt
C;lUSC.
Keyoncl a suspicion of its presrricc in assc)ciation with the conditions listed: the identification of ILGR remains difficult despitth the various methods now available. Measurement of maternal girth together with the: failure of the Inother to gain weight as proposed by McClure Browne affords a read) and practical clinical criterion to suggest that the fetus is failing to grow in accordance with normal expectations.” The oxamination of the various components of amniotic fluid is yielding useful information as are serial measurements of the biparietal diameter of the fetal head by ultrasound. However, all of thr current methods half some diagnostic limitations in the individual case, and none is capable of documenting thr exact time of onset of intrauterine nialnutrition.7 It is the purpose of this paper to explore a maternal parameter that may possibly assist in the identification of the syndrome and time of onset. The question is posed whether certain of the clotting factors may. on occasion, reach a hypercoagulable state in IUGK. It has been demonstrated that this can occur in preconvulsive toxemia. and in the presence of a dead baby syndrome.‘5 In contrast to local clotting. the hypercoagulable state is associated with a generalized systemic clotting reaction. It may be IYgarded as the preconsumptive phase, albeit subclinical, of disseminated intravascular clotting which in the extreme results in a hypocoagulable state or a hemorrhagic diathesis. That a hypercoagulable state may be associated with IUGR must take into account the changes in the clotting mechanism ill normal pregnancy. It is accepted that certain of the procoagulant factors involved in the intrinsic clotting mechanism, especially Factor VIII, are increased in normal preqnancy, and these arch reflected in a partial‘ thromboplastin time ( PTT‘) and Quick time.‘j The observations to be reported are regarded as preliminary, and their clinical validity and possible usefulness will depend on more casrs carefully categori;led.
Volume Number
Hypercoagulabiiity
111 7
Methods
and
their
interpretation
Bleeding times were done by the Ivy technique. Platelets were counted by the phase microscopic method of Brecher and Cronkite.3 Platelet adhesiveness was determined by a glass bead column method adapted from Salzman.17 Platelet aggregation was evaluated by the method of Pavlovsky14 following addition of 0.5 ,JJper milliliter of adenosine diphosphate. PTT’s were based on the procedure of Langdell, Wagner, and Brinkhous.l” Prothrombin times were performed by the method of Quick. Recalcified clotting times were based on platelet-rich plasma obtained by centrifuging an admixture of 4.5 ml. of venous blood and 0.5 ml. of sodium citrate at 1,000 r.p.m. for 5 minutes. After incubation at 37’ C. for 3 minutes with 0.2 ml. of such platelet-rich plasma, 0.2 ml. of 0.025M calcium chloride was added. The time for appearance of a clot was recorded as the average of 3 tests. Glass and silicone clotting times were completed at the bedside with the use of the two-syringe technique and reported as the average on 4 and 6 appropriately prepared tubes as times from the time of venipuncture. Euglobulin lysis, serial thrombin times, and turbidometric fibrinogen assays were completed respectively by the methods of Blik, Reid, and associates1G and Fonell. Ethanol gelation tests were performed by the Breen-Tulli9 procedure. The patient’s blood was drawn into special anticoagulant solution (a buffered citrate) which is essential for this test. A general interpretation of the hemostatic and coagulation assays used in this study is presented in order to state what they measure, what they do not measure, and their reliability and significance, if any. Tests to measure activation of intrinsic and/or extrinsic clotting. Clotting time. The normal glass clotting time is generally less than 14 minutes. Blood collected in siliconized tubes normally clots in from 30 to 60 min., and the test is useful in studies concerned with hypercoagulability.
in dysmature
syndrome
869
The difference between silicone and glass clotting time is ascribed to Hageman factor activation and indicates that the early phases of the intrinsic clotting system have been triggered. The relationship of silicone clotting time to glass clotting time is here expressed as a ratio, with the normal value in pregnancy being greater than 2:l and the normal in the nonpregnant woman being 3: 1. Ratios between 2:l and 1:l are assumed to indicate the presence of circulating activated surface factor consistent with a hypercoagulable state. Partial thrombofdastin time. The PTT is unaffected by platelet abnormalities and is used to diagnose defects of the first stage of clotting. Thus, its prolongation is presumed to represent deficiencies of either Factors VIII, IX, X, or XI. A shortening of the PTT is believed to be an indication of the presence of circulating serum factors or an excess of procoagulants. Prothrombin time. The “prothrombincomplex” consists of Factors II, VII, IX, and X. All but Factor IX can be measured by the over-all Q,uick time, which also measures Factor V. Shortening of the Quick time. This was assumed to indicate the presence in plasma of either activation or of excesses of any of the factors of the prothrombin complex. Tests to measure platelet adhesiveness and platelet aggregation. Platelet adhesiveness normally varies between 20 and 80 per cent and is generally believed to have no meaning within this broad range. An excess adherence of platelets to the column (> 80 per cent) has been reported to occur in thrombotic states. Platelet aggregation, the first step in hemostasis, when increased over normal levels, as expressed as less than 50 per cent, is assumed to reflect the presence of platelet thrombi. Uremia and drugs such as aspirin and tranquilizers interfere with normal platelet aggregation, Tests which measure fibrinogen consumption or degradation. Fibrin. monomers. When fibrinogen is acted upon by thrombin, Fibrinopeptides A and B are split off, and the remaining fibrin monomers then polymerize to form a clot. Recent
870
Frigoletto
et al.
Table I. Clotting
factors
-normal
G.C.T. Sil. C.T.
Normal
’ Q.T. (sec.)
lReca1. ](min.)
Eth. / eel.
STT
; lhg. / lysis
i ml. / ndh !(% )
; / Platelet&
I’ll. U.&x. (%I
/ ~Fibrin / Cm3~
3.0
42
14.0
60.2
0
N
0
250,400
45
Normal first trimester of pregnancy (10)
2 ,3
39.4,
11.6
69.6
0
N
o
264,660
i4.6
. j ii, ‘,_
246
Normal third trimester of pregnancy ( 10)
2.6
39.1
12.3
69.
0
N
(1
280,720
49.7
-48.8
3 13
C.C.T. gel IIcss.Ht.
Eth.
nonpregnant
I ! Pl’T (sec.)
values
=
slass clotting time. Sil. C. T. = silicone ethanol g&t&n. STT = serial thrombin ass. = platrlet aggrrgation. N = normal. =
clotting time. Q. time Eue. lysis
assays to describe their presence (ethanol gelation and serial dilution protamine test) are difficult to reproduce, but when positive they are a specific indication that the intrinsic system has been activated. Fibrinogen degradation products. When fibrinogen is acted upon by fibrinolysin and many other proteolytic enzymes, a series of degradation products is formed. Thrombolytic activity in this study was assayed by gross clot lysis and by the serial thrombin time. Increases in the activators of fibrinolysis were measured by euglobulin clot lysis. Results Table I lists the results obtained in normal nonpregnant women and normal patients in both the first and third trimesters of pregnancy. Tables II, III, and IV are serial determinations of coagulation and hemostatic factors carried out during the pregnancies of 3 patients who clinically had small infants for their gestational ages. Table II shows a progressive shortening of the glass-to-silicone clotting-time ratio and a shortening of the PTT and the Quick time. In addition, there is an increase in platelet aggregation as pregnancy progressed. On the third postpartum day, the values have returned almost to the normal nonpregnant levels, with the rxception of the PTT, indicating continued elevation of the procoagulant factors and the normal glass-to-silicone clotting-time ratio denoting disappearance of surface activators, Factors XI and XII. Table III shows the significant lowering of the glass-to-silicone clotting-time ratio
1‘. =- quick z euglobulin
timr, lysis.
40
to
50
230
Krcal. = ~ecalrification time. Pit. adb. = platelet adhesiw-
and the rather marked shortening of the PTT and the Quick time as well as a positive ethanol gelation test. Platelet aggregation is also increased. The parameters being measured as listed in Table III returned to normal following complete heparinization of the patient with subsequent return to the pretreatment levels following discontinuation of this therapy. Table IV, in addition to substantiating the data of Tables II and III, shows a moderate reduction in platelets as pregnancy progressed. It also reveals. at least in the parameters studied, no difference for the values obtained between uterine vein and peripheral vein blood collected simultaneously. Urinary estriol levels in all instances were low. Also. in several patients where clinically the fetus appeared not to be growing but at delivery was of normal weight for gestational age, no drviations in the clotting mechanisni were encountered. Comment In clinical conditions where the fetus fails to thrive in utero, measurable changes in the procoagulant factors of the clotting mechanism consistent with a hypercoagulable state can be observed. In considering the meaning of these findings, one must recognize that thrre are similar changes but to a lesser degree that occur in normal pregnancy which are evident as early as the first trimester. Although this accentuation in the clotting mechanism may be endocrine-inspired, why it should occur and for what possible purpose have been the subjects of teleo-
syndrome
2.5 2.5 1.8 1.6 1.2 1.4 2.8
3.0 2.6
G.C.T. Sil. C.T.
12.2 12.2 11.6 10.8 12.0 11.8 13.0
(sec.) 14.0 12.3
(sec.) 42 39.1
43.4 40.2 43.7 38.0 43.0 40.0 38.0
Q.T.
PTT
80 75 84 81 76 62.4 a5
(min.) 60.2 69
Recal.
.
0 0 0 0 0 0 0
gel. 0 0
Eth.
N N N N N N N
N N
STT
0 0 0 0 0 0 0
0 0
Eug. lysis
233,000 332,000 262,000 266,000 270,000 222,000 255,000
250,400 280,720
Platelets
13" 46 48 43 62 59
45 49.7
Plt. adh. /%J
-39.3 -42 -58 -59 -51 -44
-40 to -50 -48.8
Pk. aw (9% J
323 290 300 320 260 360 480
230 313
Fibrin (mn.)
6/16 7/17 8/10 g/g 9/22 10/2
Date
4.3 5.6 5.4 8.0 12.0 10.9
1 mg./24
Estriol hr.
*Ingesting
aspirin.
E. Z. is a 31-year-old woman, gravida 2, paza 1, whose past significant history includes chronic pyelonephritis with a nonpregnant blood urea nitrogen of 40 mg. per cent and blood pressure of 14O/SO. Her first p egnancy was complicated by severe IUGR and neonatal death; for the last half of the present pregnancy, she was treated with total hospital bed rest. At approximately 35 woks, a 3 pound, 1 ounce dysmature infant IVZIS dclivercd by repeat ccsarean se&our. The placenta was small 2nd mature; there we e extensive recent and old infarcts-focal decidual necrosis.
7/22 8/20 9/10 9/24 10/2 delivered 10/5 post partum
718
E. Z.
Normal nonpregnant Normal third trimester of pregnancy
Table II. Dysmature
III. Dysmature
(4)
heparin (4) delivered post partum
heparin
heparin
nonpregnant third trimester
Normal Normal nancy
J. G. 2/lf 3/2 3/5 3j6 - 3/9 .%/IO
IV. Dysmature
Table
B. B. is a 37-year-old section at the thirty-seventh knotting.
B. B. 5/13 5/21 5/28 6/10 6/16
Normal nonpregnant Normal third trimester pregnancy
Table
I__.-
1.5 3.4 1.6 2.4 2.7
G.C.T. Sil. C.T.
30.0 63.9 31.8 38.0 30.2
42 39.1
PTT (sec.)
10.0 14.1 11.8 12.1 10.8
14.0 12.3
Q.T. (sec. I
I
56.4 182.6 64.6 173.8 68.3
60.2 69
Recal. f min.)
!
t 0 0 0 0
0 0
Eth. eel.
N N N N N
N N
STT
0 0 0 0 0
0 0
Eug. lysis
preg-
1.8
2.0 1.7 2.2
3.0 2.6
G.C.?'.C.T. 1/I 5’;l.
41.5
37.3 39.1 38.2
42 39.1
/ (sec.) PTZ
10.9
9 3 11.0 11.0
14.0 12.3
I1 y.)
64.7
50.6 64.2 78
60.2 69
1 Recnl, p&iz3
0
0 0 0
0 (I
N
N N N
N N
~ $
-__-___..-..
0
0 0 0
0 0
woma~~. ql-avida 8, pal-a 6. with hypt.ltrnaion and normal rcrral function, blood urea trek of a 4 nound, 5 ounce dysmaturr infant. Tiw small mature piarrnta trvealrd
of
syndrome
169,000
202,400 222,200 187,000
250,400 280,720
~ Platelets
nitrogen of a marginal
268,400 268,400 255,200 305,800 325,600
250,400 280,720
Platelets
63
45.6 34 54
-40
-48
-44 -53 -39
to --50 -48.8
/1 “;;:;“.
of protein. thxmhi.
-36.3 -56.0 -74.0 -55.5 -37.5
Pk. aa. (“/-) -40 to -50 -48.8
wine frcr intrrrillous
45 49.7
1 gj
10, and infarct,
51 36 75 46 34
45 49.7
Pk. adh. (56)
6/l 6/2
5/12 5/19
I--....-1 Date
385
305 300 305
230 313
1 F;;F
‘jl6 311 3/5 3j8
/ 6;tpy~$2/i
7.1 9.3 6.2 7.8
hi:
1 I.? il.? 1’3.4 I?.!
hr,
by ccsarean in ryncytial
Estriol /ng./24
She was delivrlcd and focal inct case
465 420 400 340 505
230 313
Fibrin (ma.)
-
03
Volume Number
111 7
logic speculation, It has been suggested that these changes are conducive to ensuring effective hemostasis at the placental site at the time of parturition. (2) It would be equally pertinent for some degree of fibrin deposition to occur in and about the intervillous space to maintain its integrity where the supporting structure, the decidua, is undergoing constant growth and regression. At any rate, fibrin appears on the placenta about the tenth week of gestation. Certainly the maternal organism must adjust and contend with a unique structure introduced into the vascular system, the intervillous space. Here the blood is exposed to a large endothelial-like surface and sometimes at a sluggish rate of flow, created by the venous back pressure when in the upright position or pressure by the uterus on the inferior vena cava when in the supine position and possible impairment of blood flow to the intervillous space. To avoid clotting under these circumstances, could it be that the blood flowing through the endomyometrial vasculature to enter and depart from the intervillous space is influenced by the heparin-containing mast cells that are reportedly present in large numbers in the myometrium. Regardless, the homeostasis of the blood flowing in the intervillous space may be in jeopardy whenever the morphology of the structure or its villous contents is altered.
Hypercoagulability
in dysmature
Hence, it might be postulated
syndrome
873
that defects
in the endothelial-like lining of the intervillous space and possibly the trophoblast may activate the intrinsic clotting mechanism resulting in a hypercoagulable state, in some cases associated with the small-for-dates baby. The parameters of the intrinsic mechanism of clotting, notably the glass-tosilicone clotting time and PTT, may revert to normal with the administration of heparin, but whether this has therapeutic benefit remains to be studied. The patients presented all had small placentas with some infarction and fibrin deposition, the changes listed as being associated with IUGR syndrome. But whether a hypercoagulable state may develop in the presence of a placenta that is relatively normal is open to question. Certainly, the placentas from patients with the syndrome of IUGR may reveal no apparent abnormalities. Therefore, no cause-and-effect relationship between a hypercoagulable state and IUGR is intended in this study. Rather, in some cases the syndrome might be identified and the time of its onset might be determined by searching for evidence of changes in clotting factors beyond those of normal pregnancy. The authors Flannery, Miss Baudanza who tion assays and
are indebted to Mrs. Chloris M. Ann T. Breed, and Miss Phyllis were responsible for the coagulahemostatic tests of this study.
REFERENCES
1. Battaglia, F. C.: AM. J. OBSTET. GYNECOL. 106: 1103, 1970. 2. Bonnar, J., McNicol, G. P., and Douglas, A. 3. 4. 5. 6. 7. 8. 9. 10.
11.
S.: Brit. Med. J. 2: 200, 1970. Brecher, G., and Cronkite, E. P.: J. Appl. Physiol. 3: 365, 1950. Breen, F. A., and Tullis, J. L.: Ann. Intern. Med. 69: 1197, 1968. Clifford, S. H.: J. Pediatr. 44: 1, 1954. Elliott, P.: Amt. N. Z. J. Obstet. Gynaecol. 7: 13, 1967. Fetal maturity, Br. Med. J. 4: 129, 1970. Growth-rate in utero, Lancet 1: 765, 1967. Haworth, J. C., Dilling, L., and Younoszai, M. K.: Lancet 2: 901. 1967. Langdell, R. D.: Wagner, R. H., and Brinkhous, K. M.: J. Lab. Clin. Med. 41: 637, 1953. Lubchenco, L. O., Hansman, Cl., Dressler, M.,
and
Boyd,
E.: Pediatrics 32: 793, 1963. Browne, J. C.: Dysmaturity-postmaturity, in Reid, D. E., and Barton, T. C., editors: Controversy in Obstetrics and Gynecology, Philadelphia, 1969, W. B. Saunders Company, p. 102. Nutrition and the developing brain, Brit. Med. J. 1: 333, 1968. Pavlosky, M.: Medicina 28: 1968. Reid, D. E., Frigoletto, F. D., Tullis, J. L., and Hinman, J.: AM. J. OBSTET. GYNECOL. 111: 493, 1971. Reid, W. L., Somlyo, A. V., Somlyo, A. P., and Custer, R. P.: Am. J. Clin. Pathol. 37: 561, 1962. Salzman, E. W.: J. Lab. Clin. Med. 62: 724, 1963. Scott, K. E., and Usher, R.: AM. J. OBSTET. GYNECOL. 94: 951, 1966.
12. McClure
13. 14. 15.
16.
17. 18.
111 .December
American
Journal
number
7
1, 1971
of Obstetrics and Gynecology
OBSTETRICS
Hypercoagulability in the dysmature syndrome FREDRIC JAMES DUNCAN
D. L.
FRIGOLETTO,
TULLIS, E.
JOHN
HINMAN,
Boston,
Massachusetts
M.D. M.D.
REID,
M.D. M.D.
A discordance between gestational age and fetal weight has been recognized clinically since the turn of the century. The failure to maintain a normal growth rate in utero is referred to as the “dysmature syndrome” or intrauterine growth retardation. Several etiologies, notably hypertensive pregnancy and renal disease, have been assigned to this syndrome, but in many of the cases there has been no demonstrable associated cause. It is proposed that an aberration of the clotting mechanism may play a role in some cases of intrauterine growth retardation. Cases are presented where a subclinical state of hypercoagulability has been encountered in the presence of intrauterine growth retardation, as measured by the presence of fibrin monomers, platelet function, and other factors related to the preconsumptive phase of the clotting mechanism.
SINCE THE writings of Ballantyne even before, those responsible for the From the Department Gynecology and the Medicine, Harvard England Deaconess Boston Hospital for
and care
of the parturient and her infant have wondered whether the characteristic appearance of the postmature infant, notably the absence of vernix caseosa and the discoloration and desquamation of the skin, had any significance. Clifford5 in 1954 challenged, as had others, the commonly held belief that the postmature infant was of excessive size due to the continuous growth; he contended that the reverse occurred and described and classified in some detail the appearance of these newborn infants and coined the term placental dysfunction to account for the observed changes in the skin and the wasting
of Obstetrics and Department of Medical School, New Hospital, and the Women.
The funds for this study were made possible by National Institutes of Health Grant No. 2-PO-I-HE-06302-10 to the Blood Research Institute, and Institutional Grant No. FRO5481-08 to the Boston Hospital for Women. Presented by Duncan E. Reid, M.D., on May 19, 1971, at the Nineteenth British Congress of Obstetrics and Gynaecology, Dublin, Ireland. 867
868
Frigoletto
et al.
of thr subcutaneous tissue. It was further concluded that the placental dysfunction syndrome can occur at any gestational age. Moreover, it is no\v recognized that failure to grow in utero may become a clinical problem from the twenty-sixth, twenty-eighth, and thirtieth weeks onward and in fact the fetus may be suffering from the effects of malnutrition even prior to this period. Now more commonly referred to as intrauterine growth retardation (IUGR) , the condition by definition is present when the neonate’s weight falls below the tenth percentile in accordance with the Denver intrauterine weight curve for infants of that particular gestational age.l’ Although the survival rate of the growth-retarded infant may be higher than an infant of comparable weight not so afflicted (the latter presumably of less gestational age), the ultimate development of these malnourished infants has been of increasing concern.‘, (i. i;. IS Indeed, there is a growing body of evidence to suggest that a major source of central nervous system damage of the newborn infant may reside in the fetuses that have experienced some degree of intrauterine malnutrition. Certainly lack of proper nutrition in the newborn period can adversely influence the brain, hence mental as well as physical development.“’ Whether the central nervous system deficiencies of these fetuses can be corrected after birth is a matter of controversy and debate. Beginning with Nelligan’s observation of a hypoglycemic state and confirmed by Cornblith and others, measurable metabolic alterations are present at birth in these infants.” This raises the proposition that if the fetus is to escape irreversible damage from intrauterine malnutrition the latter niust be recognized at the earliest moment and if possible corrected in utero. IUGR has been attributed to a host of causes, including rarely viral diseases and chromosomal disorders.‘. Ii Actually, the failure to grow in utero is encountered most frequently in a variety of obstetric states from deviations in placentation to renal disease and hypertension. but in some instances
the syndrornfb
occur:,
IL lthout
:trly appareilt
C;lUSC.
Keyoncl a suspicion of its presrricc in assc)ciation with the conditions listed: the identification of ILGR remains difficult despitth the various methods now available. Measurement of maternal girth together with the: failure of the Inother to gain weight as proposed by McClure Browne affords a read) and practical clinical criterion to suggest that the fetus is failing to grow in accordance with normal expectations.” The oxamination of the various components of amniotic fluid is yielding useful information as are serial measurements of the biparietal diameter of the fetal head by ultrasound. However, all of thr current methods half some diagnostic limitations in the individual case, and none is capable of documenting thr exact time of onset of intrauterine nialnutrition.7 It is the purpose of this paper to explore a maternal parameter that may possibly assist in the identification of the syndrome and time of onset. The question is posed whether certain of the clotting factors may. on occasion, reach a hypercoagulable state in IUGK. It has been demonstrated that this can occur in preconvulsive toxemia. and in the presence of a dead baby syndrome.‘5 In contrast to local clotting. the hypercoagulable state is associated with a generalized systemic clotting reaction. It may be IYgarded as the preconsumptive phase, albeit subclinical, of disseminated intravascular clotting which in the extreme results in a hypocoagulable state or a hemorrhagic diathesis. That a hypercoagulable state may be associated with IUGR must take into account the changes in the clotting mechanism ill normal pregnancy. It is accepted that certain of the procoagulant factors involved in the intrinsic clotting mechanism, especially Factor VIII, are increased in normal preqnancy, and these arch reflected in a partial‘ thromboplastin time ( PTT‘) and Quick time.‘j The observations to be reported are regarded as preliminary, and their clinical validity and possible usefulness will depend on more casrs carefully categori;led.
Volume Number
Hypercoagulabiiity
111 7
Methods
and
their
interpretation
Bleeding times were done by the Ivy technique. Platelets were counted by the phase microscopic method of Brecher and Cronkite.3 Platelet adhesiveness was determined by a glass bead column method adapted from Salzman.17 Platelet aggregation was evaluated by the method of Pavlovsky14 following addition of 0.5 ,JJper milliliter of adenosine diphosphate. PTT’s were based on the procedure of Langdell, Wagner, and Brinkhous.l” Prothrombin times were performed by the method of Quick. Recalcified clotting times were based on platelet-rich plasma obtained by centrifuging an admixture of 4.5 ml. of venous blood and 0.5 ml. of sodium citrate at 1,000 r.p.m. for 5 minutes. After incubation at 37’ C. for 3 minutes with 0.2 ml. of such platelet-rich plasma, 0.2 ml. of 0.025M calcium chloride was added. The time for appearance of a clot was recorded as the average of 3 tests. Glass and silicone clotting times were completed at the bedside with the use of the two-syringe technique and reported as the average on 4 and 6 appropriately prepared tubes as times from the time of venipuncture. Euglobulin lysis, serial thrombin times, and turbidometric fibrinogen assays were completed respectively by the methods of Blik, Reid, and associates1G and Fonell. Ethanol gelation tests were performed by the Breen-Tulli9 procedure. The patient’s blood was drawn into special anticoagulant solution (a buffered citrate) which is essential for this test. A general interpretation of the hemostatic and coagulation assays used in this study is presented in order to state what they measure, what they do not measure, and their reliability and significance, if any. Tests to measure activation of intrinsic and/or extrinsic clotting. Clotting time. The normal glass clotting time is generally less than 14 minutes. Blood collected in siliconized tubes normally clots in from 30 to 60 min., and the test is useful in studies concerned with hypercoagulability.
in dysmature
syndrome
869
The difference between silicone and glass clotting time is ascribed to Hageman factor activation and indicates that the early phases of the intrinsic clotting system have been triggered. The relationship of silicone clotting time to glass clotting time is here expressed as a ratio, with the normal value in pregnancy being greater than 2:l and the normal in the nonpregnant woman being 3: 1. Ratios between 2:l and 1:l are assumed to indicate the presence of circulating activated surface factor consistent with a hypercoagulable state. Partial thrombofdastin time. The PTT is unaffected by platelet abnormalities and is used to diagnose defects of the first stage of clotting. Thus, its prolongation is presumed to represent deficiencies of either Factors VIII, IX, X, or XI. A shortening of the PTT is believed to be an indication of the presence of circulating serum factors or an excess of procoagulants. Prothrombin time. The “prothrombincomplex” consists of Factors II, VII, IX, and X. All but Factor IX can be measured by the over-all Q,uick time, which also measures Factor V. Shortening of the Quick time. This was assumed to indicate the presence in plasma of either activation or of excesses of any of the factors of the prothrombin complex. Tests to measure platelet adhesiveness and platelet aggregation. Platelet adhesiveness normally varies between 20 and 80 per cent and is generally believed to have no meaning within this broad range. An excess adherence of platelets to the column (> 80 per cent) has been reported to occur in thrombotic states. Platelet aggregation, the first step in hemostasis, when increased over normal levels, as expressed as less than 50 per cent, is assumed to reflect the presence of platelet thrombi. Uremia and drugs such as aspirin and tranquilizers interfere with normal platelet aggregation, Tests which measure fibrinogen consumption or degradation. Fibrin. monomers. When fibrinogen is acted upon by thrombin, Fibrinopeptides A and B are split off, and the remaining fibrin monomers then polymerize to form a clot. Recent
870
Frigoletto
et al.
Table I. Clotting
factors
-normal
G.C.T. Sil. C.T.
Normal
’ Q.T. (sec.)
lReca1. ](min.)
Eth. / eel.
STT
; lhg. / lysis
i ml. / ndh !(% )
; / Platelet&
I’ll. U.&x. (%I
/ ~Fibrin / Cm3~
3.0
42
14.0
60.2
0
N
0
250,400
45
Normal first trimester of pregnancy (10)
2 ,3
39.4,
11.6
69.6
0
N
o
264,660
i4.6
. j ii, ‘,_
246
Normal third trimester of pregnancy ( 10)
2.6
39.1
12.3
69.
0
N
(1
280,720
49.7
-48.8
3 13
C.C.T. gel IIcss.Ht.
Eth.
nonpregnant
I ! Pl’T (sec.)
values
=
slass clotting time. Sil. C. T. = silicone ethanol g&t&n. STT = serial thrombin ass. = platrlet aggrrgation. N = normal. =
clotting time. Q. time Eue. lysis
assays to describe their presence (ethanol gelation and serial dilution protamine test) are difficult to reproduce, but when positive they are a specific indication that the intrinsic system has been activated. Fibrinogen degradation products. When fibrinogen is acted upon by fibrinolysin and many other proteolytic enzymes, a series of degradation products is formed. Thrombolytic activity in this study was assayed by gross clot lysis and by the serial thrombin time. Increases in the activators of fibrinolysis were measured by euglobulin clot lysis. Results Table I lists the results obtained in normal nonpregnant women and normal patients in both the first and third trimesters of pregnancy. Tables II, III, and IV are serial determinations of coagulation and hemostatic factors carried out during the pregnancies of 3 patients who clinically had small infants for their gestational ages. Table II shows a progressive shortening of the glass-to-silicone clotting-time ratio and a shortening of the PTT and the Quick time. In addition, there is an increase in platelet aggregation as pregnancy progressed. On the third postpartum day, the values have returned almost to the normal nonpregnant levels, with the rxception of the PTT, indicating continued elevation of the procoagulant factors and the normal glass-to-silicone clotting-time ratio denoting disappearance of surface activators, Factors XI and XII. Table III shows the significant lowering of the glass-to-silicone clotting-time ratio
1‘. =- quick z euglobulin
timr, lysis.
40
to
50
230
Krcal. = ~ecalrification time. Pit. adb. = platelet adhesiw-
and the rather marked shortening of the PTT and the Quick time as well as a positive ethanol gelation test. Platelet aggregation is also increased. The parameters being measured as listed in Table III returned to normal following complete heparinization of the patient with subsequent return to the pretreatment levels following discontinuation of this therapy. Table IV, in addition to substantiating the data of Tables II and III, shows a moderate reduction in platelets as pregnancy progressed. It also reveals. at least in the parameters studied, no difference for the values obtained between uterine vein and peripheral vein blood collected simultaneously. Urinary estriol levels in all instances were low. Also. in several patients where clinically the fetus appeared not to be growing but at delivery was of normal weight for gestational age, no drviations in the clotting mechanisni were encountered. Comment In clinical conditions where the fetus fails to thrive in utero, measurable changes in the procoagulant factors of the clotting mechanism consistent with a hypercoagulable state can be observed. In considering the meaning of these findings, one must recognize that thrre are similar changes but to a lesser degree that occur in normal pregnancy which are evident as early as the first trimester. Although this accentuation in the clotting mechanism may be endocrine-inspired, why it should occur and for what possible purpose have been the subjects of teleo-
syndrome
2.5 2.5 1.8 1.6 1.2 1.4 2.8
3.0 2.6
G.C.T. Sil. C.T.
12.2 12.2 11.6 10.8 12.0 11.8 13.0
(sec.) 14.0 12.3
(sec.) 42 39.1
43.4 40.2 43.7 38.0 43.0 40.0 38.0
Q.T.
PTT
80 75 84 81 76 62.4 a5
(min.) 60.2 69
Recal.
.
0 0 0 0 0 0 0
gel. 0 0
Eth.
N N N N N N N
N N
STT
0 0 0 0 0 0 0
0 0
Eug. lysis
233,000 332,000 262,000 266,000 270,000 222,000 255,000
250,400 280,720
Platelets
13" 46 48 43 62 59
45 49.7
Plt. adh. /%J
-39.3 -42 -58 -59 -51 -44
-40 to -50 -48.8
Pk. aw (9% J
323 290 300 320 260 360 480
230 313
Fibrin (mn.)
6/16 7/17 8/10 g/g 9/22 10/2
Date
4.3 5.6 5.4 8.0 12.0 10.9
1 mg./24
Estriol hr.
*Ingesting
aspirin.
E. Z. is a 31-year-old woman, gravida 2, paza 1, whose past significant history includes chronic pyelonephritis with a nonpregnant blood urea nitrogen of 40 mg. per cent and blood pressure of 14O/SO. Her first p egnancy was complicated by severe IUGR and neonatal death; for the last half of the present pregnancy, she was treated with total hospital bed rest. At approximately 35 woks, a 3 pound, 1 ounce dysmature infant IVZIS dclivercd by repeat ccsarean se&our. The placenta was small 2nd mature; there we e extensive recent and old infarcts-focal decidual necrosis.
7/22 8/20 9/10 9/24 10/2 delivered 10/5 post partum
718
E. Z.
Normal nonpregnant Normal third trimester of pregnancy
Table II. Dysmature
III. Dysmature
(4)
heparin (4) delivered post partum
heparin
heparin
nonpregnant third trimester
Normal Normal nancy
J. G. 2/lf 3/2 3/5 3j6 - 3/9 .%/IO
IV. Dysmature
Table
B. B. is a 37-year-old section at the thirty-seventh knotting.
B. B. 5/13 5/21 5/28 6/10 6/16
Normal nonpregnant Normal third trimester pregnancy
Table
I__.-
1.5 3.4 1.6 2.4 2.7
G.C.T. Sil. C.T.
30.0 63.9 31.8 38.0 30.2
42 39.1
PTT (sec.)
10.0 14.1 11.8 12.1 10.8
14.0 12.3
Q.T. (sec. I
I
56.4 182.6 64.6 173.8 68.3
60.2 69
Recal. f min.)
!
t 0 0 0 0
0 0
Eth. eel.
N N N N N
N N
STT
0 0 0 0 0
0 0
Eug. lysis
preg-
1.8
2.0 1.7 2.2
3.0 2.6
G.C.?'.C.T. 1/I 5’;l.
41.5
37.3 39.1 38.2
42 39.1
/ (sec.) PTZ
10.9
9 3 11.0 11.0
14.0 12.3
I1 y.)
64.7
50.6 64.2 78
60.2 69
1 Recnl, p&iz3
0
0 0 0
0 (I
N
N N N
N N
~ $
-__-___..-..
0
0 0 0
0 0
woma~~. ql-avida 8, pal-a 6. with hypt.ltrnaion and normal rcrral function, blood urea trek of a 4 nound, 5 ounce dysmaturr infant. Tiw small mature piarrnta trvealrd
of
syndrome
169,000
202,400 222,200 187,000
250,400 280,720
~ Platelets
nitrogen of a marginal
268,400 268,400 255,200 305,800 325,600
250,400 280,720
Platelets
63
45.6 34 54
-40
-48
-44 -53 -39
to --50 -48.8
/1 “;;:;“.
of protein. thxmhi.
-36.3 -56.0 -74.0 -55.5 -37.5
Pk. aa. (“/-) -40 to -50 -48.8
wine frcr intrrrillous
45 49.7
1 gj
10, and infarct,
51 36 75 46 34
45 49.7
Pk. adh. (56)
6/l 6/2
5/12 5/19
I--....-1 Date
385
305 300 305
230 313
1 F;;F
‘jl6 311 3/5 3j8
/ 6;tpy~$2/i
7.1 9.3 6.2 7.8
hi:
1 I.? il.? 1’3.4 I?.!
hr,
by ccsarean in ryncytial
Estriol /ng./24
She was delivrlcd and focal inct case
465 420 400 340 505
230 313
Fibrin (ma.)
-
03
Volume Number
111 7
logic speculation, It has been suggested that these changes are conducive to ensuring effective hemostasis at the placental site at the time of parturition. (2) It would be equally pertinent for some degree of fibrin deposition to occur in and about the intervillous space to maintain its integrity where the supporting structure, the decidua, is undergoing constant growth and regression. At any rate, fibrin appears on the placenta about the tenth week of gestation. Certainly the maternal organism must adjust and contend with a unique structure introduced into the vascular system, the intervillous space. Here the blood is exposed to a large endothelial-like surface and sometimes at a sluggish rate of flow, created by the venous back pressure when in the upright position or pressure by the uterus on the inferior vena cava when in the supine position and possible impairment of blood flow to the intervillous space. To avoid clotting under these circumstances, could it be that the blood flowing through the endomyometrial vasculature to enter and depart from the intervillous space is influenced by the heparin-containing mast cells that are reportedly present in large numbers in the myometrium. Regardless, the homeostasis of the blood flowing in the intervillous space may be in jeopardy whenever the morphology of the structure or its villous contents is altered.
Hypercoagulability
in dysmature
Hence, it might be postulated
syndrome
873
that defects
in the endothelial-like lining of the intervillous space and possibly the trophoblast may activate the intrinsic clotting mechanism resulting in a hypercoagulable state, in some cases associated with the small-for-dates baby. The parameters of the intrinsic mechanism of clotting, notably the glass-tosilicone clotting time and PTT, may revert to normal with the administration of heparin, but whether this has therapeutic benefit remains to be studied. The patients presented all had small placentas with some infarction and fibrin deposition, the changes listed as being associated with IUGR syndrome. But whether a hypercoagulable state may develop in the presence of a placenta that is relatively normal is open to question. Certainly, the placentas from patients with the syndrome of IUGR may reveal no apparent abnormalities. Therefore, no cause-and-effect relationship between a hypercoagulable state and IUGR is intended in this study. Rather, in some cases the syndrome might be identified and the time of its onset might be determined by searching for evidence of changes in clotting factors beyond those of normal pregnancy. The authors Flannery, Miss Baudanza who tion assays and
are indebted to Mrs. Chloris M. Ann T. Breed, and Miss Phyllis were responsible for the coagulahemostatic tests of this study.
REFERENCES
1. Battaglia, F. C.: AM. J. OBSTET. GYNECOL. 106: 1103, 1970. 2. Bonnar, J., McNicol, G. P., and Douglas, A. 3. 4. 5. 6. 7. 8. 9. 10.
11.
S.: Brit. Med. J. 2: 200, 1970. Brecher, G., and Cronkite, E. P.: J. Appl. Physiol. 3: 365, 1950. Breen, F. A., and Tullis, J. L.: Ann. Intern. Med. 69: 1197, 1968. Clifford, S. H.: J. Pediatr. 44: 1, 1954. Elliott, P.: Amt. N. Z. J. Obstet. Gynaecol. 7: 13, 1967. Fetal maturity, Br. Med. J. 4: 129, 1970. Growth-rate in utero, Lancet 1: 765, 1967. Haworth, J. C., Dilling, L., and Younoszai, M. K.: Lancet 2: 901. 1967. Langdell, R. D.: Wagner, R. H., and Brinkhous, K. M.: J. Lab. Clin. Med. 41: 637, 1953. Lubchenco, L. O., Hansman, Cl., Dressler, M.,
and
Boyd,
E.: Pediatrics 32: 793, 1963. Browne, J. C.: Dysmaturity-postmaturity, in Reid, D. E., and Barton, T. C., editors: Controversy in Obstetrics and Gynecology, Philadelphia, 1969, W. B. Saunders Company, p. 102. Nutrition and the developing brain, Brit. Med. J. 1: 333, 1968. Pavlosky, M.: Medicina 28: 1968. Reid, D. E., Frigoletto, F. D., Tullis, J. L., and Hinman, J.: AM. J. OBSTET. GYNECOL. 111: 493, 1971. Reid, W. L., Somlyo, A. V., Somlyo, A. P., and Custer, R. P.: Am. J. Clin. Pathol. 37: 561, 1962. Salzman, E. W.: J. Lab. Clin. Med. 62: 724, 1963. Scott, K. E., and Usher, R.: AM. J. OBSTET. GYNECOL. 94: 951, 1966.
12. McClure
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16.
17. 18.