Factors associated with preterm delivery in women with type 1 diabetes - A cohort study

OBJECTIVE - The reported rate of preterm delivery in women With type 1 diabetes ranges from 22 to 45%, but the reasons are unclear. The purpose of this study was to identify factors associated with preterm delivery in these women. RESEARCH DESIGN AND METHODS - We studied the influence of maternal and diabetes-related factors on the occurrence of preterm delivery in 168 single pregnancies occurring in 127 women with type 1 diabetes. Women with spontaneous or indicated preterm delivery were compared with those who delivered after 37 weeks of gestation using polytomous logistic regression. RESULTS - The overall rate of preterm delivery was 24%, fivefold higher than the French prematurity rate in single pregnancy. Preterm delivery was spontaneous in 9% and indicated in 15%. HbA(1c) greater than or equal to7% at delivery was associated with spontaneous preterm delivery (odds ratio [OR] 5.3 [95% CI 1.1-26.8]). Nulliparity (12.0 [2.3-64.1]), progression of nephropathy (7.7 [1.3-46.9]), preeclampsia (12.0 [3.1-47.1]), and HbA(1c) greater than or equal to7% (7.5 [1.5-37.9]) at delivery were all associated with indicated preterm delivery. Preterm delivery was associated with significant neonatal morbidity as the risks for neonatal hypoglycemia and respiratory distress syndrome were increased by three- to sixfold compared with the reference group. CONCLUSIONS - The rate of preterm delivery remains high in women with type 1 diabetes. Different factors were associated with spontaneous and indicated preterm delivery, respectively. Because poor glycemic control was a risk factor for both outcomes, part of preterm delivery might be preventable.