Association of Maternal Obesity in Early Pregnancy with Adverse Pregnancy Outcomes: A Chinese Prospective Cohort Analysis

Objective This study aimed to examine the associations of maternal obesity in early pregnancy with adverse pregnancy outcomes. Methods A prospective cohort analysis was performed among 18,481 Chinese nulliparous women, using data from a 2006 to 2009 trial of prenatal micronutrient supplementation. Obesity was defined as BMI >= 27.5 kg/m(2). Interested outcomes included fetal loss (spontaneous abortion plus stillbirth), infant death, total mortality, and preterm and birth weight outcomes. Results Compared with normal weight, obesity was associated with total mortality (adjusted relative risks [ARR] 1.34; 95% CI: 1.03-1.74) and fetal loss (ARR 1.51; 95% CI: 1.15-1.99) but not with infant death (ARR 0.53; 95% CI: 0.20-1.46). Further analyses showed that obesity was particularly associated with spontaneous abortion (ARR 1.51; 95% CI: 1.13-2.02) rather than stillbirth (ARR 1.52; 95% CI: 0.65-3.57). Moreover, obesity was associated with preterm birth (ARR 1.59; 95% CI: 1.25-2.02), macrosomia (ARR 3.71, 95% CI: 3.01-4.59), and large for gestational age (ARR 2.93; 95% CI: 2.49-3.47). Conclusions Maternal obesity in early pregnancy is associated with various adverse pregnancy outcomes in Chinese nulliparous women, suggesting the importance of an appropriate weight before and during pregnancy.