Diabetes and Birth Defects

cdc.gov, Feb 23, 2007

Women with diabetes have a higher risk for complications of pregnancy than do women without diabetes; in addition, infants born to women with diabetes are at increased risk for adverse birth outcomes (1,2). Preconception counseling for women with established diabetes and early and continual prenatal care for women with established or gestational diabetes can reduce maternal and infant morbidity and mortality (3). Although the rate of pregnancy complicated by diabetes and the use of prenatal care varies by race of the mother (4), it is unknown whether the effect of diabetes on maternal and infant outcomes differs by race. Race reflects differing distributions of several risk factors for pregnancy outcomes (e.g., socioeconomic status and access to comprehensive health care) and is useful for identifying groups at greatest risk for adverse outcomes. To determine the prevalence of diabetes during pregnancy among women residing in North Carolina and to characterize differences in prenatal care and the risk for maternal complications and adverse pregnancy outcomes by race among mothers with diabetes, the North Carolina State Center for Health and Environmental Statistics examined birth certificates of infants of women who gave birth in the state during 1989-1990. This report summarizes the findings of the study. For births occurring during 1989-1990, singleton live births to North Carolina residents were identified from computerized matched live birth and infant death records. Mothers with diabetes were identified by a check box for diabetes in the medical history section of the infant's birth certificate. The check box does not distinguish between established and gestational diabetes in pregnancy.

For comparison, a computer-generated 7% random sample of live births with no mention of diabetes was selected. Birth certificates were reviewed to obtain information about maternal complications (i.e., polyhydramnios, pregnancy-induced hypertension, and pre eclampsia/eclampsia) and perinatal outcomes (i.e., macrosomia, birth injury, and hyaline membrane disease/respiratory distress syndrome) and maternal age, maternal race, and prenatal-care initiation. For infants who died before age 1 year, age at death was ascertained from the infant's death certificate. Logistic regression was used to determine odds ratios (ORs) and 95% confidence intervals (CIs) for the association between maternal diabetes, age, race, and selected pregnancy outcomes. An interaction term between maternal diabetes and race was included in the models to determine whether the relation between maternal diabetes and adverse events differed by race. For this analysis, maternal race was presented for blacks and other minority races combined * and for whites. From January 1, 1989, through December 31, 1990, there were 201,823 singleton live births to North Carolina residents. Of these, 6092 (3%) women had a history of maternal diabetes (4451 white mothers and 1641 minority mothers). The prevalence of diabetes during pregnancy was 326.8 per 10,000 live births for white women and 251.7 per 10,000 live births for minority women. The prevalence increased with age of the mother for both racial groups. For women aged less than 30 years, pregnancies complicated by diabetes occurred 1.5 (Woolf 95% CI=1.4-1.6) times more often among white women than among minority women; for women aged greater than or equal to 30 years, pregnancies complicated by diabetes were 1.3 (Woolf 95% CI=1.1-1.4) times more likely in minority women.

Among women with pregnancies complicated by diabetes, 12.6% of white women and 24.7% of minority women initiated prenatal care during their second or third trimesters. Less than 1% of mothers reported with diabetes received no prenatal care. Among women with a pregnancy complicated by diabetes, those aged greater than or equal to 30 years were more likely to initiate prenatal care during their first trimester than were those aged less than 30 years. Compared with white women without diabetes, the risk for maternal complications was approximately two times greater among white mothers with diabetes and two to four times greater among minority mothers with diabetes; however, differences in risks between white and minority women with diabetes were not statistically significant (0.40 less than p less than 0.75). When compared with infants born to white women without diabetes, infants of all women with diabetes were nearly twice as likely to experience a birth injury. The risk for infant mortality was greater in babies born to women with diabetes, especially after controlling for differences in birthweight. The risk for neonatal mortality varied significantly (p=0.04) by racial group. Congenital malformations accounted for 31.3% of the deaths among infants of mothers with diabetes. Reported by: RE Meyer, PhD, PA Buescher, PhD, State Center for Health and Environmental Statistics; K Ryan, MD, Div of Maternal and Child Health; North Carolina Dept of Environment, Health, and Natural Resources, Raleigh, North Carolina. Epidemiology and Statistics Br, Div of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion, CDC.

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