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Birth weight, gestational age, and perinatal deaths in 5,471 infants of diabetic mothers
March 1977
444
TheJournalofPEDlATRICS
Birth weight, gestational age, and perinatal deaths in 5,471 infants of diabetic mothers A. Frederick North, Jr.,* Sati Mazumdar, and Vito M. Logrillo,
Pittsburgh, Pa.,
a n d AIbany, N. Y.
ALTHOUGH HIGHER BIRTH WEIGHT and increased fetal and neonatal deaths are well-known features of pregnancy in diabetic women, '-4 the relative infrequency of diabetes in pregnancy has precluded statistical study of the interrelationships of birth weight, gestational age, and fetal and neonatal deaths. This report explores these interrelations for a group of 5,471 singleton infants of white diabetic mothers for the years 1958 through 1969. Comparison is made with 2,000,688 singleton infants of nondiabetic white women born during the same period. MATERIAL
AND METHODS
Data on all reported live births and fetal and neonatal deaths occurring in New York State (exclusive in New York City) have all been recorded on magnetic tape and analyzed by computer. Fetal deaths were defined as stillbirths occurring after 20 weeks' gestation. Neonatal deaths were defined as deaths of live-born infants prior to age 28 days. Pregnancies of diabetic women included all those for whom maternal diabetes was recorded as a complication on the birth or fetal death certificate. The accuracy and completeness with which this complication was recorded is not known, and the diabetes was not classified by time of onset or severity. Crestational age was calculated from the recorded date of the last menstrual period. Birth weight was accepted as recorded on the birth and fetal death certificates. Only singleton births to white women were analyzed. From the School of Medicine and Graduate School of Public" Health, University of Pittsburgh, and the Ojfice of Biostatistics New York State Department of Health. *Reprint address: Graduate School of Public Health, University of Pittsburgh, Pittsburgh. PA 15261.
Vol. 90, No. 3, pp. 444-447
RESULTS
Birth weight and gestational age. Table I shows the distribution by birth weight of IDM's and INDM's born alive at each gestational age. At each gestational age, IDM's are overrepresented in the high-birth weight categories, whereas they are overrepresented in the low-birth weight categories only in the 37- to 40-week gestational age group. Table II shows that the excess of high birth weight for gestational age is even more marked for stillborn IDM's and that there is no excess of low birth weight for gestational age among stillborn IDM's. Abbreviations used IDM: infant of diabetic mothers IDNM: infant of nondiabetic mothers The marginal percentages in Tables I and II show that there is an excess of both low and high birth weights among live-born IDM's and a marked excess of high birth weight's among stillborn IDM's. A much higher proportion of IDM's than INDM's are born alive before 37 weeks' gestation, while a lower proportion of IDM's are stillborn before 28 weeks' gestation and a much higher proportion between 33 and 40 weeks gestation. These data show that the high incidence of low birth weight in IDM's is almost entirely a function of foreshortened gestation, while the high incidence of high birth weight is a function of more rapid intrauterine growth. Fetal and neonatal deaths. Table III shows the fetal, neonatal, and perinatal death rates at each gestational age for infants of diabetic and nondiabetic women, and Table IV shows the cumulative deaths and survivals of IDM's at each gestational age. Fetal and neonatal deaths were more frequent.in lDM's at every gestational age. Both the absolute risk of fetal
Volume90 Number 3
Weight, age, and deaths in IDM
445
T a b l e I. Distribution by birth weight a n d gestational age o n live-born infants o f diabetic a n d n o n d i a b e t i c w o m e n
% of births by birth weight(gm) Gestationalage (wk)
%of births
20-28
Diabetic Nondiabetic 29-32 Diabetic Nondiabetic 33-36 Diabetic Nondiabetic 37-40 Diabetic Nondiabetic 41-44 Diabetic Nondiabetic > 44 Diabetic Nondiabetic All gestational ages Diabetic Nondiabetic
1:3 0.6 2.7 0.8 23.0 3.6 67.5 84.5 5.2 10.3 0.3 0.3 100 I00
1,501-I 1,750
1,751- ] 2,251- [ 2,50l- ] 3,001- [ 3,5012,250 2,500 3,000 3,500 4,500
69.8 84.5 17.2 30.9 1.0 2.0 0.1 0.03 0.0 0.02 0.0 0.1
11.1 5.3 10.2 20.8 1.5 3.6 0.1 0.06 0.0 0.03 0.0 0.1
6.4 4.3 26.6 29.0 8.1 '24.0 1.3 0.9 0.4 0.4 0.0 0.9
4.8 0.9 13.3 6.4 9.4 19.3 2.8 2.6 0.8 1.1 0.0 2.1
1.6 1.6 18.8 6.2 24.3 28.1 17.8 19.8 7.2 11.0 7.7 13.6
1.6 2.0 7.8 4.6 26.1 15.5 29.5 41.3 29.6 35.8 23.1 36.1
4.8 1.4 5.5 2.2 25.7 7.4 39.9 34. t 49.6 48.6 30.8 44.2
0.0 0.1 0.8 0.1 4.0 0.2 8.5 1.2 12.4 3.1 38.5 2.9
1.7 0.9
0.8 0.4
3.6 1.9
4.5 3. I
18.5 18.9
27.8 39.2
35.7 34.3
7.4 1.4
<1,500
]
>4,500
Diabetic women: N = 4,796. Nondiabetic women: N = 1,976,977. Table II. Distribution by birth weight at each gestational age o f fetal deaths in diabetic and n o n d i a b e t i c w o m e n
% of births by birth weight(gm) Gestationalage (wk)
% of all births
20-28
Diabetic Nondiabetic 29-32 Diabetic Nondiabetic 33-36 Diabetic Nondiabetic 37-40 Diabetic Nondiabetic 41-44 Diabetic Nondiabetic > 44 Diabetic Nondiabetic All gestational ages Diabetic Nondiabetic
1,500
1,5011,750
11.7 27.0 10.1 12.4 28.4 17.7 44.6 36.7 4.9 5.9 0.3 0.3
89.9 94.0 42.6 62.3 14.1 28.1 5.0 5.1 3.0 1.4
6.3 2.3 8.8 11.7 5.2 10.5 0.7 3.5 1.4
I00 100
21.4 40.1
3.4 5.3
1751 1 2251 2,250 -
2,500 1.3
25Ol 3,000 -
3,500 2.5
I 5ol
4,500 -
4,500 -
22.1 16.5 13.0 24.5 3.7 10.5 3.0 5.2
0.6 5.9 4.9 8.3 12.8 3.7 10.2 6.1 6.9
0.3 7.4 3.0 19.3 14.0 11.6 23.6 6.1 18.6
0.3 4.4 1.0 14.1 6.7 16.3 25.2 28.1
0.2 7.4 0.4 19.3 2.7 33.6 18.8 45.5 32.2
1.5 0.1 6.8 0.5 25.6 3.2 36.4 5.9
7.7 11.2
5.0 7.2
11.7 12.8
12.0 12.4
23.6 9.5
15.4 1.6
2.2
Diabetic women: N = 675. Nondiabetic women: N = 23.711. d e a t h a n d the relative risk (as c o m p a r e d with n o n d i a b e t i c pregnancies) increased m a r k e d l y with a d v a n c i n g gestational age. T h e fetal d e a t h rate o f 123.4 in I D M ' s was 10.4 times that in I N D M ' s . T h e absolute risk o f n e o n a t a l deaths in I D M ' s decreased with a d v a n c i n g gestational age ( t h r o u g h 44 weeks) but the relative risk, c o m p a r e d with I N D M ' s , was highest after 37 weeks' gestation. T a b l e V shows the neonatal mortality rates o f I D M ' s for each birth weight a n d gestational age. T a b l e VI shows the
risk ratio (rate in I D M ' s - rate in I N D M ' s ) in each birth weight and gestational age category. T h e risk o f n e o n a t a l d e a t h is higher a m o n g I D M ' s in every birth weight for gestational age category. T h e absolute risk o f n e o n a t a l d e a t h is lowest in infants b o r n after 40 weeks' gestation and weighing m o r e t h a n 3,500 g m a m o n g b o t h I D M ' s a n d I N D M ' s . However, the relative risk (diabetic versus nondiabetic) is highest in the n o r m a l a n d high birth weight categories regardless o f
446
North, Mazumdar, and Logrillo
The Journal of Pediatrics March 1977
Table IlL Fetal, neonatal, and perinatal death rates Fetal death rate Gestational age (wk)
Diabetic
20-28 29-32 33-36 37-40 41-44 > 44 All gestationa[ ages
556.3 346.9 148.2 85.1 116.6 133.3 123.4
Nondiabetic
345.9 156.2 56.5 5.2 6.9 13.7 11.9
Table IV. Cumulative fetal and neonatal deaths and survivals at each gestational age in pregnancies in diabetic women
Gestational age (wk)
Live fetuses (%)
Fetal deaths (%)
Neonatal deaths (%)
Live surviving infants (%)
100 97.4 93.8 70.1 5.5 0.3 0
0 1.4 2.7 6.2 11.7 12.3 12.6
0 1.0 2.1 4.4 6.3 6.4 6.4
0 0.1 1.4 19.3 78.3 80.5 81.0
At 20 By 28 By 32 By 36 By 40 By 44 All pregnancies
gestational age, and the absolute number of excess neonatal deaths is also highest in these large infants of diabetic mothers. DISCUSSION The reported prevalence of diabetes in pregnant women, 2.7/1,000 pregnancies, was higher than the 1/ 1,000 reported by White," and lower than the 6.6/1,000 noted in the Collaborative Perinatal Study? In the present study, reporting on birth certificates was undoubtedly incomplete, and no differentiation could be made between pre-existing diabetes and gestational diabetes, or between frank symptomatic diabetes and diabetes manifested solely by an abnormal glucose tolerance test (found in an additional 7.5/1,000 in the Collaborative Study.) The fetal death rate of 126/1,000 in diabetic pregnancies is similar to the rate of 104/1,000 reported by Gellis and Hsia,'-' and higher than the 80/1,000 reported in the Collaborative Study.:' The neonatal death rate of 73/1,000 is similar to the 69/1,000 of the Collaborative Study:' and much lower than the 131/1,000 reported by Gellis and HsiaY The total perinatal mortality rate of 190 is similar to that reported by Gellis and Hsias Hubell and colleagues, 7 Essex and associates? Williger," Pedersen and associates,'"
Neonatal death rate Diabetic
873.0 484.4 111.4 33.1 12.0 76.9 73.2
Nondiabetic
770.7 294.9 55.4 4.9 4.5 8.0 ]3.7
Perinatal death rate Diabetic I
943.7 663.3 243.1 115.3 127.2 200.0 I87.5
Nondiabetic
850.0 405.0 108.7 10.1 11.3 12.3 254.4
and Dekaban and Baird ~' for infants born between 1945 and 1965, but substantially higher than that of the Collaborative Study ~ (144) or the more recent experience of Pedersen and colleagues'" (103). These differences reflect at least three factors which differ distinctly in the reported series: the proportion of diabetes which is gestational rather than pre-existing (mortality rates are much lower in gestational diabetes)? the prevailing method of pregnancy management (early delivery by cesarean section undoubtedly partially accounts for the lower fetal and higher neonatal mortality rates in the series of Gellis and Hsia~), and improvement in survival associated with more recent methods of management (most impressively documented by Essex" and by Pedersen '~' and their co-workers). It seems most likely that birth certificate data used in this study would underreport mild and gestational diabetes. The excess weight of live-born IDM's has been noted frequently, but has never previously been documented by gestational age. Management, which in the past often included induction or cesarean section at 37 weeks' gestation, confounded the comparison of "average" birth weights. For example, in the Collaborative Study:' the mean birth weight of infants of diabetic mothers was only 21 gm greater than that of infants of nondiabetic mothers. An increased prevalence of "small-for-dates" infants among IDM's was noted by Farquhar, l but it has not previously been demonstrated that this excess occurs only among IDM's born after gestations of 37 to 40 weeks. Farquhar' stated that "the (excessive) mortality does not fall upon the fat giants but rather on the extremely premature and on babies who are light'-for-dates." The data here reported support an opposite conclusion-it is the ~'large-for-dates'" fetuses and infants who are at the greatest relative risk. SUMMARY
The birth weight, gestational age, and fetal and neonatal mortality rates in 5,471 singleton infants of white
Volume 90 Number 3
Weight, age, and deaths in I D M
447
Table V. Neonatal death rates by gestational age and birth weight in infants of diabetic mothers
Birth weight (gm)
less
1,501 to 1,750
1,751 to 2,250
2,251 to 2,500
2,501 to 3,000
1,000.0 863.6 545.5 666.7 * *
714.3 615.4 250.0 250.0 * *
750.0 500.0 236.0 232.6 0.0 *
666.7 352.9 182.7 109.9 0.0 *
0.0 333,3 97.0 45.1 55.6 0.0
Gestational age (wk)
1,500
28 and less 29-32 33-36 37-40 41-44 > 44
or
3,001to
l
3,501to
3,500
4,500
4,501 +
0.0 300.0 62.5 22.0 13.5 333.3
0.0 142.9 88.0 18.6 8.1 0.0
* 0.0 90,9 47.5 0.0 0.0
*There were no live births in these birth weight-gestational age categories.
Table VI. Risk ratio* for neonatal death in infants of diabetic mothers by birth weight and gestational age
Birth weight (gin)
1,501_ 1 1,751. 2,251_ 1,750 2,250 2,500
2, 01_ E 3,001_ E 3,501_ t 4,501 3,000 3,500 4,500 +
Gestational age (wk)
O1,500
20-28 29-32 33-36 37-40 41-44 > 44
1.15 1.66 1.33 1.93 t
1.67 2.09 1.16 1.20 t
2.61 2.45 2.71 3.99 t
4.75 2.79 4.03 5.22 t
t 5.01 3.72 6.93 7.19
t
t
t
t
t
t 9.16 5.25 6.97 3.96 3.75
t 4.89 8.48 6.78 2.76
t t 3.11 7.01 t
t
t
*Ratio of neonatal mortality rate in infants of diabetic mothers to neonatal mortality rate in infants of nondiabetic mothers. tThese birth weigbt-gestational age categories contained no neonatal deaths for infants of diabetic mothers.
diabetic women, born between 1950 and 1969, have been compared with data from 2,000,688 singleton pregnancies in white nondiabetic women. 1. An excess of high birth weights was found in both stillborn and live-born infants of diabetic mothers at all gestational ages. 2. An excess of low birth weight was found in live-born (but not stillborn) infants of diabetic mothers at 37 to 40 weeks' gestation but not at other gestational ages. 3. The fetal death rate in infants o f diabetic mothers exceeded that of infants of nondiabetic mothers at all gestational ages. It increased with gestational age and was most excessive after 32 weeks' gestation. The fetal death rate was 10.4 times that in nondiabetic pregnancies. 4. The death rate in infants of diabetic mothers exceeded that of infants of nondiabetic mothers at all gestational ages and in every birth-weight-for-gestationalage category. The relative risk and the absolute n u m b e r of excessive neonatal deaths was highest among infants with normal and high birth weights. Infants of diabetic mothers had a neonatal mortality rate nearly 5 1/2 times that o f infants o f nondiabetic mothers. 5. O f each 1,000 fetuses of diabetic mothers alive at 20 weeks' gestation, 126 were stillborn, 64 died in the neonatal period, and 810 survived at least 28 days after birth. O f each, 1,000 fetuses of nondiabetic women, 12
were stillborn, 14 died in the neonatal period, and 974 survived. REFERENCES
1. Farquhar JW: The infant of the diabetic mother. Postgrad Med J (Suppl) 1:806, 1969. 2. Gellis SS, and Hsia DYY: The infant of the diabetic mother, Am J Dis Child 97:1, 1959. 3. Dekaban A, and Baird R: The outcome of pregnancy in diabetic women. I. Fetal wastage, mortality and morbidity in the offspring of diabetic and normal control mothers, J PEDIATR 55:563, 1959. 4. Farquhar JW: Birth weight and survival of babies of diabetic women, Arch Dis Child 37:321, 1962. 5. Niswander KR, and Gordon M: The Collaborative Perinatal Study of the National Institute of Neurological Disease and Stroke: The women and their pregnancies, Philadelphia, 1972, W B Saunders Company pp 239-245. 6. White P: Pregnancy and diabetes, medical aspects, Med Clin North Am 49:1015, 1965. 7. Hubell JP, Muirhead DM, and Drorbaugh JE: The newborn infant of the diabetic mother, Med Clin North Am 49:1035. 1965. 8. Essex NL, et al: Diabetic pregnancy, Br Med J 4:89, 1973. 9. Williger VM: Fetal outcome in the diabetic pregnancy, Am J Obset Crynecol 94:57, 1966. 10. Pedersen L Molsted-Pedersen L, and Anderson B: Assessors of fetal and perinatal mortality in diabetic pregnancy: analysis of 1332 pregnancies in the Copenhagen seriem 1946-1972, Diabetes 23:302, 1974.
444
TheJournalofPEDlATRICS
Birth weight, gestational age, and perinatal deaths in 5,471 infants of diabetic mothers A. Frederick North, Jr.,* Sati Mazumdar, and Vito M. Logrillo,
Pittsburgh, Pa.,
a n d AIbany, N. Y.
ALTHOUGH HIGHER BIRTH WEIGHT and increased fetal and neonatal deaths are well-known features of pregnancy in diabetic women, '-4 the relative infrequency of diabetes in pregnancy has precluded statistical study of the interrelationships of birth weight, gestational age, and fetal and neonatal deaths. This report explores these interrelations for a group of 5,471 singleton infants of white diabetic mothers for the years 1958 through 1969. Comparison is made with 2,000,688 singleton infants of nondiabetic white women born during the same period. MATERIAL
AND METHODS
Data on all reported live births and fetal and neonatal deaths occurring in New York State (exclusive in New York City) have all been recorded on magnetic tape and analyzed by computer. Fetal deaths were defined as stillbirths occurring after 20 weeks' gestation. Neonatal deaths were defined as deaths of live-born infants prior to age 28 days. Pregnancies of diabetic women included all those for whom maternal diabetes was recorded as a complication on the birth or fetal death certificate. The accuracy and completeness with which this complication was recorded is not known, and the diabetes was not classified by time of onset or severity. Crestational age was calculated from the recorded date of the last menstrual period. Birth weight was accepted as recorded on the birth and fetal death certificates. Only singleton births to white women were analyzed. From the School of Medicine and Graduate School of Public" Health, University of Pittsburgh, and the Ojfice of Biostatistics New York State Department of Health. *Reprint address: Graduate School of Public Health, University of Pittsburgh, Pittsburgh. PA 15261.
Vol. 90, No. 3, pp. 444-447
RESULTS
Birth weight and gestational age. Table I shows the distribution by birth weight of IDM's and INDM's born alive at each gestational age. At each gestational age, IDM's are overrepresented in the high-birth weight categories, whereas they are overrepresented in the low-birth weight categories only in the 37- to 40-week gestational age group. Table II shows that the excess of high birth weight for gestational age is even more marked for stillborn IDM's and that there is no excess of low birth weight for gestational age among stillborn IDM's. Abbreviations used IDM: infant of diabetic mothers IDNM: infant of nondiabetic mothers The marginal percentages in Tables I and II show that there is an excess of both low and high birth weights among live-born IDM's and a marked excess of high birth weight's among stillborn IDM's. A much higher proportion of IDM's than INDM's are born alive before 37 weeks' gestation, while a lower proportion of IDM's are stillborn before 28 weeks' gestation and a much higher proportion between 33 and 40 weeks gestation. These data show that the high incidence of low birth weight in IDM's is almost entirely a function of foreshortened gestation, while the high incidence of high birth weight is a function of more rapid intrauterine growth. Fetal and neonatal deaths. Table III shows the fetal, neonatal, and perinatal death rates at each gestational age for infants of diabetic and nondiabetic women, and Table IV shows the cumulative deaths and survivals of IDM's at each gestational age. Fetal and neonatal deaths were more frequent.in lDM's at every gestational age. Both the absolute risk of fetal
Volume90 Number 3
Weight, age, and deaths in IDM
445
T a b l e I. Distribution by birth weight a n d gestational age o n live-born infants o f diabetic a n d n o n d i a b e t i c w o m e n
% of births by birth weight(gm) Gestationalage (wk)
%of births
20-28
Diabetic Nondiabetic 29-32 Diabetic Nondiabetic 33-36 Diabetic Nondiabetic 37-40 Diabetic Nondiabetic 41-44 Diabetic Nondiabetic > 44 Diabetic Nondiabetic All gestational ages Diabetic Nondiabetic
1:3 0.6 2.7 0.8 23.0 3.6 67.5 84.5 5.2 10.3 0.3 0.3 100 I00
1,501-I 1,750
1,751- ] 2,251- [ 2,50l- ] 3,001- [ 3,5012,250 2,500 3,000 3,500 4,500
69.8 84.5 17.2 30.9 1.0 2.0 0.1 0.03 0.0 0.02 0.0 0.1
11.1 5.3 10.2 20.8 1.5 3.6 0.1 0.06 0.0 0.03 0.0 0.1
6.4 4.3 26.6 29.0 8.1 '24.0 1.3 0.9 0.4 0.4 0.0 0.9
4.8 0.9 13.3 6.4 9.4 19.3 2.8 2.6 0.8 1.1 0.0 2.1
1.6 1.6 18.8 6.2 24.3 28.1 17.8 19.8 7.2 11.0 7.7 13.6
1.6 2.0 7.8 4.6 26.1 15.5 29.5 41.3 29.6 35.8 23.1 36.1
4.8 1.4 5.5 2.2 25.7 7.4 39.9 34. t 49.6 48.6 30.8 44.2
0.0 0.1 0.8 0.1 4.0 0.2 8.5 1.2 12.4 3.1 38.5 2.9
1.7 0.9
0.8 0.4
3.6 1.9
4.5 3. I
18.5 18.9
27.8 39.2
35.7 34.3
7.4 1.4
<1,500
]
>4,500
Diabetic women: N = 4,796. Nondiabetic women: N = 1,976,977. Table II. Distribution by birth weight at each gestational age o f fetal deaths in diabetic and n o n d i a b e t i c w o m e n
% of births by birth weight(gm) Gestationalage (wk)
% of all births
20-28
Diabetic Nondiabetic 29-32 Diabetic Nondiabetic 33-36 Diabetic Nondiabetic 37-40 Diabetic Nondiabetic 41-44 Diabetic Nondiabetic > 44 Diabetic Nondiabetic All gestational ages Diabetic Nondiabetic
1,500
1,5011,750
11.7 27.0 10.1 12.4 28.4 17.7 44.6 36.7 4.9 5.9 0.3 0.3
89.9 94.0 42.6 62.3 14.1 28.1 5.0 5.1 3.0 1.4
6.3 2.3 8.8 11.7 5.2 10.5 0.7 3.5 1.4
I00 100
21.4 40.1
3.4 5.3
1751 1 2251 2,250 -
2,500 1.3
25Ol 3,000 -
3,500 2.5
I 5ol
4,500 -
4,500 -
22.1 16.5 13.0 24.5 3.7 10.5 3.0 5.2
0.6 5.9 4.9 8.3 12.8 3.7 10.2 6.1 6.9
0.3 7.4 3.0 19.3 14.0 11.6 23.6 6.1 18.6
0.3 4.4 1.0 14.1 6.7 16.3 25.2 28.1
0.2 7.4 0.4 19.3 2.7 33.6 18.8 45.5 32.2
1.5 0.1 6.8 0.5 25.6 3.2 36.4 5.9
7.7 11.2
5.0 7.2
11.7 12.8
12.0 12.4
23.6 9.5
15.4 1.6
2.2
Diabetic women: N = 675. Nondiabetic women: N = 23.711. d e a t h a n d the relative risk (as c o m p a r e d with n o n d i a b e t i c pregnancies) increased m a r k e d l y with a d v a n c i n g gestational age. T h e fetal d e a t h rate o f 123.4 in I D M ' s was 10.4 times that in I N D M ' s . T h e absolute risk o f n e o n a t a l deaths in I D M ' s decreased with a d v a n c i n g gestational age ( t h r o u g h 44 weeks) but the relative risk, c o m p a r e d with I N D M ' s , was highest after 37 weeks' gestation. T a b l e V shows the neonatal mortality rates o f I D M ' s for each birth weight a n d gestational age. T a b l e VI shows the
risk ratio (rate in I D M ' s - rate in I N D M ' s ) in each birth weight and gestational age category. T h e risk o f n e o n a t a l d e a t h is higher a m o n g I D M ' s in every birth weight for gestational age category. T h e absolute risk o f n e o n a t a l d e a t h is lowest in infants b o r n after 40 weeks' gestation and weighing m o r e t h a n 3,500 g m a m o n g b o t h I D M ' s a n d I N D M ' s . However, the relative risk (diabetic versus nondiabetic) is highest in the n o r m a l a n d high birth weight categories regardless o f
446
North, Mazumdar, and Logrillo
The Journal of Pediatrics March 1977
Table IlL Fetal, neonatal, and perinatal death rates Fetal death rate Gestational age (wk)
Diabetic
20-28 29-32 33-36 37-40 41-44 > 44 All gestationa[ ages
556.3 346.9 148.2 85.1 116.6 133.3 123.4
Nondiabetic
345.9 156.2 56.5 5.2 6.9 13.7 11.9
Table IV. Cumulative fetal and neonatal deaths and survivals at each gestational age in pregnancies in diabetic women
Gestational age (wk)
Live fetuses (%)
Fetal deaths (%)
Neonatal deaths (%)
Live surviving infants (%)
100 97.4 93.8 70.1 5.5 0.3 0
0 1.4 2.7 6.2 11.7 12.3 12.6
0 1.0 2.1 4.4 6.3 6.4 6.4
0 0.1 1.4 19.3 78.3 80.5 81.0
At 20 By 28 By 32 By 36 By 40 By 44 All pregnancies
gestational age, and the absolute number of excess neonatal deaths is also highest in these large infants of diabetic mothers. DISCUSSION The reported prevalence of diabetes in pregnant women, 2.7/1,000 pregnancies, was higher than the 1/ 1,000 reported by White," and lower than the 6.6/1,000 noted in the Collaborative Perinatal Study? In the present study, reporting on birth certificates was undoubtedly incomplete, and no differentiation could be made between pre-existing diabetes and gestational diabetes, or between frank symptomatic diabetes and diabetes manifested solely by an abnormal glucose tolerance test (found in an additional 7.5/1,000 in the Collaborative Study.) The fetal death rate of 126/1,000 in diabetic pregnancies is similar to the rate of 104/1,000 reported by Gellis and Hsia,'-' and higher than the 80/1,000 reported in the Collaborative Study.:' The neonatal death rate of 73/1,000 is similar to the 69/1,000 of the Collaborative Study:' and much lower than the 131/1,000 reported by Gellis and HsiaY The total perinatal mortality rate of 190 is similar to that reported by Gellis and Hsias Hubell and colleagues, 7 Essex and associates? Williger," Pedersen and associates,'"
Neonatal death rate Diabetic
873.0 484.4 111.4 33.1 12.0 76.9 73.2
Nondiabetic
770.7 294.9 55.4 4.9 4.5 8.0 ]3.7
Perinatal death rate Diabetic I
943.7 663.3 243.1 115.3 127.2 200.0 I87.5
Nondiabetic
850.0 405.0 108.7 10.1 11.3 12.3 254.4
and Dekaban and Baird ~' for infants born between 1945 and 1965, but substantially higher than that of the Collaborative Study ~ (144) or the more recent experience of Pedersen and colleagues'" (103). These differences reflect at least three factors which differ distinctly in the reported series: the proportion of diabetes which is gestational rather than pre-existing (mortality rates are much lower in gestational diabetes)? the prevailing method of pregnancy management (early delivery by cesarean section undoubtedly partially accounts for the lower fetal and higher neonatal mortality rates in the series of Gellis and Hsia~), and improvement in survival associated with more recent methods of management (most impressively documented by Essex" and by Pedersen '~' and their co-workers). It seems most likely that birth certificate data used in this study would underreport mild and gestational diabetes. The excess weight of live-born IDM's has been noted frequently, but has never previously been documented by gestational age. Management, which in the past often included induction or cesarean section at 37 weeks' gestation, confounded the comparison of "average" birth weights. For example, in the Collaborative Study:' the mean birth weight of infants of diabetic mothers was only 21 gm greater than that of infants of nondiabetic mothers. An increased prevalence of "small-for-dates" infants among IDM's was noted by Farquhar, l but it has not previously been demonstrated that this excess occurs only among IDM's born after gestations of 37 to 40 weeks. Farquhar' stated that "the (excessive) mortality does not fall upon the fat giants but rather on the extremely premature and on babies who are light'-for-dates." The data here reported support an opposite conclusion-it is the ~'large-for-dates'" fetuses and infants who are at the greatest relative risk. SUMMARY
The birth weight, gestational age, and fetal and neonatal mortality rates in 5,471 singleton infants of white
Volume 90 Number 3
Weight, age, and deaths in I D M
447
Table V. Neonatal death rates by gestational age and birth weight in infants of diabetic mothers
Birth weight (gm)
less
1,501 to 1,750
1,751 to 2,250
2,251 to 2,500
2,501 to 3,000
1,000.0 863.6 545.5 666.7 * *
714.3 615.4 250.0 250.0 * *
750.0 500.0 236.0 232.6 0.0 *
666.7 352.9 182.7 109.9 0.0 *
0.0 333,3 97.0 45.1 55.6 0.0
Gestational age (wk)
1,500
28 and less 29-32 33-36 37-40 41-44 > 44
or
3,001to
l
3,501to
3,500
4,500
4,501 +
0.0 300.0 62.5 22.0 13.5 333.3
0.0 142.9 88.0 18.6 8.1 0.0
* 0.0 90,9 47.5 0.0 0.0
*There were no live births in these birth weight-gestational age categories.
Table VI. Risk ratio* for neonatal death in infants of diabetic mothers by birth weight and gestational age
Birth weight (gin)
1,501_ 1 1,751. 2,251_ 1,750 2,250 2,500
2, 01_ E 3,001_ E 3,501_ t 4,501 3,000 3,500 4,500 +
Gestational age (wk)
O1,500
20-28 29-32 33-36 37-40 41-44 > 44
1.15 1.66 1.33 1.93 t
1.67 2.09 1.16 1.20 t
2.61 2.45 2.71 3.99 t
4.75 2.79 4.03 5.22 t
t 5.01 3.72 6.93 7.19
t
t
t
t
t
t 9.16 5.25 6.97 3.96 3.75
t 4.89 8.48 6.78 2.76
t t 3.11 7.01 t
t
t
*Ratio of neonatal mortality rate in infants of diabetic mothers to neonatal mortality rate in infants of nondiabetic mothers. tThese birth weigbt-gestational age categories contained no neonatal deaths for infants of diabetic mothers.
diabetic women, born between 1950 and 1969, have been compared with data from 2,000,688 singleton pregnancies in white nondiabetic women. 1. An excess of high birth weights was found in both stillborn and live-born infants of diabetic mothers at all gestational ages. 2. An excess of low birth weight was found in live-born (but not stillborn) infants of diabetic mothers at 37 to 40 weeks' gestation but not at other gestational ages. 3. The fetal death rate in infants o f diabetic mothers exceeded that of infants of nondiabetic mothers at all gestational ages. It increased with gestational age and was most excessive after 32 weeks' gestation. The fetal death rate was 10.4 times that in nondiabetic pregnancies. 4. The death rate in infants of diabetic mothers exceeded that of infants of nondiabetic mothers at all gestational ages and in every birth-weight-for-gestationalage category. The relative risk and the absolute n u m b e r of excessive neonatal deaths was highest among infants with normal and high birth weights. Infants of diabetic mothers had a neonatal mortality rate nearly 5 1/2 times that o f infants o f nondiabetic mothers. 5. O f each 1,000 fetuses of diabetic mothers alive at 20 weeks' gestation, 126 were stillborn, 64 died in the neonatal period, and 810 survived at least 28 days after birth. O f each, 1,000 fetuses of nondiabetic women, 12
were stillborn, 14 died in the neonatal period, and 974 survived. REFERENCES
1. Farquhar JW: The infant of the diabetic mother. Postgrad Med J (Suppl) 1:806, 1969. 2. Gellis SS, and Hsia DYY: The infant of the diabetic mother, Am J Dis Child 97:1, 1959. 3. Dekaban A, and Baird R: The outcome of pregnancy in diabetic women. I. Fetal wastage, mortality and morbidity in the offspring of diabetic and normal control mothers, J PEDIATR 55:563, 1959. 4. Farquhar JW: Birth weight and survival of babies of diabetic women, Arch Dis Child 37:321, 1962. 5. Niswander KR, and Gordon M: The Collaborative Perinatal Study of the National Institute of Neurological Disease and Stroke: The women and their pregnancies, Philadelphia, 1972, W B Saunders Company pp 239-245. 6. White P: Pregnancy and diabetes, medical aspects, Med Clin North Am 49:1015, 1965. 7. Hubell JP, Muirhead DM, and Drorbaugh JE: The newborn infant of the diabetic mother, Med Clin North Am 49:1035. 1965. 8. Essex NL, et al: Diabetic pregnancy, Br Med J 4:89, 1973. 9. Williger VM: Fetal outcome in the diabetic pregnancy, Am J Obset Crynecol 94:57, 1966. 10. Pedersen L Molsted-Pedersen L, and Anderson B: Assessors of fetal and perinatal mortality in diabetic pregnancy: analysis of 1332 pregnancies in the Copenhagen seriem 1946-1972, Diabetes 23:302, 1974.