Obstetrics
Preterm delivery in women with pregestational diabetes mellitus or chronic hypertension relative to women with uncomplicated pregnancies,☆☆

https://doi.org/10.1067/mob.2000.107621Get rights and content

Abstract

Objective: The purpose of this study was to compare the rates of indicated and spontaneous preterm delivery among women with chronic hypertension or pregestational diabetes mellitus with the rates among healthy women. Study Design: This was a secondary analysis of data from healthy women with singleton gestations enrolled in a prospective observational study for prediction of preterm delivery (control group, n = 2738), women with pregestational diabetes mellitus requiring insulin therapy (n = 461), and women with chronic hypertension (n = 761). The two latter groups were enrolled in a randomized multicenter trial for prevention of preeclampsia. The main outcome measures were rates of preterm delivery, either spontaneous (preterm labor or rupture of membranes) or indicated (for maternal or fetal reasons), and neonatal outcomes. Results: The overall rates of preterm delivery were significantly higher among women with diabetes mellitus (38%) and hypertension (33.1%) than among control women (13.9%). Rates were also significantly higher for delivery at <35 weeks’ gestation. Women with diabetes mellitus had significantly higher rates of both indicated preterm delivery (21.9% vs 3.4%; odds ratio, 8.1; 95% confidence interval, 6.0-10.9) and spontaneous preterm delivery (16.1% vs 10.5%; odds ratio, 1.6; 95% confidence interval, 1.2-2.2) than did women in the control group. In addition, they had significantly higher rates of both indicated preterm delivery (odds ratio, 4.8; 95% confidence interval, 3.0-7.5) and spontaneous preterm delivery (odds ratio, 2.1; 95% confidence interval, 1.4-3.0) at <35 weeks’ gestation than did control women. Compared with control women those with chronic hypertension had higher rates of indicated preterm delivery at both <37 weeks’ gestation (21.9% vs 3.4%; odds ratio, 8.1; 95% confidence interval, 6.2-10.6) and at <35 weeks’ gestation (12.1% vs 1.6%; odds ratio, 8.2; 95% confidence interval, 5.7-11.9), but there were no differences in rates of spontaneous preterm delivery. Conclusion: The increased rate of preterm delivery among women with chronic hypertension relative to control women was primarily an increase in indicated preterm delivery, whereas the rates of both spontaneous and indicated preterm delivery were increased among women with pregestational diabetes mellitus. (Am J Obstet Gynecol 2000;183:1520-4.)

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Material and methods

The study population consisted of women enrolled in protocols that were designed and carried out by members of the Maternal-Fetal Medicine Units Network of the National Institute of Child Health and Human Development.6, 11 The study group included women with singleton pregnancies who had pregestational diabetes mellitus requiring insulin therapy or preexisting chronic hypertension and were enrolled in a multicenter randomized trial to compare low-dose aspirin with placebo for the prevention of

Results

Table I compares the baseline clinical characteristics among the 3 study groups.

. Baseline clinical characteristics among study groups

Empty CellPregestational diabetes mellitus (n = 461)Chronic hypertension (n = 761)Control (n = 2738)Statistical significance
Race (%)P <.0001
 White52.526.835.3
 Black39.360.862.8
Married (%)46.640.927.1P <.0001
Multiparous (%)49.775.356.9P <.0001
Maternal age (y, mean ± SD)25.9 ± 6.029.8 ± 6.323.5 ± 5.4P <.0001
Maternal weight (lb, mean ± SD)163.3 ± 46.7194.1 ± 58.9147.9 ± 40.0P

Comment

In this study we evaluated the rates of and the reasons for preterm delivery in a large population of women with pregestational diabetes mellitus treated with insulin or chronic hypertension and compared them with those in a healthy control woman. The rates of preterm delivery at both <37 weeks’ gestation and <35 weeks’ gestation were significantly higher in the study groups than in the control group. Among women with pregestational diabetes mellitus treated with insulin the rate of preterm

Acknowledgements

The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network was established by the Institute in 1986. In addition to the authors, the participants in the Network were as follows: J. Harger, M. Cotroneo, and T. Kamon, Magee-Women’s Hospital, Pittsburgh; B. Mercer and R. Ramsey, University of Tennessee, Memphis; Y. Rabello, D. McCart, and E. Mueller, University of Southern California, Los Angeles; R. Goldenberg and R. Copper, University of Alabama,

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Supported by grants HD 19897, HD21410, HD21414, HD21434, HD27860, HD27861, HD27869, HD27883, HD27889, HD27905, HD27915, HD27917, and HD36801 from the National Institute of Child Health and Human Development.

☆☆

Reprint requests: Baha M. Sibai, MD, Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, 231 Bethesda Ave, Rm 4415, Cincinnati, OH 45267.

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