摘要：Objectives. We examined associations between obesity, diabetes, and 3 adverse pregnancy outcomes—primary cesarean delivery, preterm birth, and low birth-weight (LBW)—by racial/ethnic group. Our goal was to better understand how these associations differentially impact birth outcomes by group in order to develop more focused interventions. Methods. Data were collected from the 1999, 2000, and 2001 New York City birth files for 329988 singleton births containing information on prepregnancy weight and prenatal weight gain. Separate logistic regressions for 4 racial/ethnic groups predicted the adverse pregnancy outcomes associated with diabetes. Other variables in the regressions included obesity, excess weight gain, hypertension, preeclampsia, and substance use during pregnancy (e.g., smoking). Results. Chronic and gestational diabetes were significant risks for a primary cesarean and for preterm birth in all women. Diabetes as a risk for LBW varied by group. For example, whereas chronic diabetes increased the risk for LBW among Asians, Hispanics, and Whites (adjusted odds ratios=2.28, 1.69, and 1.59), respectively, it was not a significant predictor of LBW among Blacks. Conclusions. In this large, population-based study, obesity and diabetes were independently associated with adverse pregnancy outcomes, highlighting the need for women to undergo lifestyle changes to help them control their weight during the childbearing years and beyond. The prevalence of diabetes among American women continues to increase, 1 , 2 with Blacks and Hispanics more likely to be affected than non-Hispanic Whites. 3 Diabetes is the most common medical complication of pregnancy. 4 In the United States in 2002, 131027 births included diabetes as a medical risk factor, translating to a rate of 32.8 per 1000 live births. 5 Because diabetes in pregnancy—both pregestational and gestational diabetes—can affect the mother and the infant, increases in the prevalence of diabetes among women of reproductive age is a public health concern. 6 The associations between pregestational and gestational diabetes, adverse pregnancy and birth outcomes, and race have been well established in the literature. Pregnant women with pregestational type 1 and type 2 diabetes are more likely to have cesarean deliveries, macrosomic infants, fetal congenital malformations, and preterm deliveries. 7 – 9 Gestational diabetes has also been associated with adverse birth outcomes, including pre-term birth, macrosomia and related shoulder dystocia, and cesarean deliveries. 10 – 15 Although both pregestational and gestational diabetes are strongly associated with higher birthweights, in the presence of vascular disease associated with diabetes, birthweight may be restricted. 4 Women with gestational diabetes have a 20% to 50% chance of developing type 2 diabetes in the next 5 to 10 years, and their offspring are at increased risk of developing diabetes and obesity later in life. 3 , 16 , 17 Obesity is a major contributing factor to the 2 most common medical risks in pregnancy: diabetes and hypertension. The incidence of hypertension and preeclampsia is increased in pregnant women with pregestational diabetes and is related to both underlying vascular disease and pregestational hypertension. 18 , 19 Obesity has also been shown to be an independent risk factor for a longer, more difficult delivery and for a cesarean delivery. 20 , 21 Although obesity is associated with an increased risk of large-for-gestational age and macrosomic infants, obese women also have an increased risk of hypertensive disorders, including preeclampsia, which may be associated with low birthweight (LBW). 22 For these reasons, the role of prepregnancy weight and pregnancy weight gain, both in terms of their relation to these medical risks and as independent predictors of pregnancy and birth outcomes, are increasingly being examined. 8 , 19 – 23 Furthermore, 1 researcher has suggested that maternal obesity and diabetes may act “synergistically” to increase the risk of noncongenital defects in newborns. 9 In pregnancy, gestational diabetes is often preexisting type 2 diabetes that has not been diagnosed. 4 The Fourth International Workshop-Conference on Gestational Diabetes and the American College of Obstetricians and Gynecologists have recommended that women of Hispanic, African, Native American, South or East Asian, Pacific Island, or Indigenous Australian ancestry, who are at higher risk for gestational diabetes, be screened for diabetes. 24 In a large prospective trial in Canada, Naylor et al. 25 identified Asian race as a risk factor for gestational diabetes. For the United States, Solomon et al. 26 found that the risk of gestational diabetes was increased among non-White women in the Nurses’ Health Study Cohort II. Given that rates of obesity and diabetes are higher among some racial and ethnic subgroups, particularly among Black women in the United States, 27 several analyses have examined the independent effects of obesity and diabetes and adverse birth outcomes by race. Saldana et al. 28 found a significant interaction between glucose status and race, so their analyses were stratified by race looking at Black and White mothers separately. There is also evidence that the obesity-related risks during pregnancy vary by race/ethnicity, with obese Hispanic and Black women more likely to have adverse outcomes than obese White women. 29 Prior research has found racial differentials in the effects of impaired glucose tolerance and glucose levels on birth outcomes, with these conditions leading to higher levels of macrosomic babies among Black women but not among White women. 28 , 30 , 31 The present analysis builds on previously published literature by using a large, population-based data set of births to the diverse population of women in New York, NY. The data set allows ample statistical power to conduct separate analyses examining the associations between diabetes, obesity, and 3 adverse pregnancy and birth outcomes—primary cesarean delivery, pre-term birth, and LBW—in women of 4 different racial and ethnic subgroups. By conducting an analysis in this way, we were able to separate subgroup disparities in the prevalence of diabetes and associated risk factors (including obesity and hypertensive disorders) from the disproportionate impact these risk factors may have on the adverse pregnancy and birth outcomes of interest.
