Rate of gestational weight gain and adverse pregnancy outcomes in rural nulliparous women: a prospective cohort analysis from China

Both inadequate and excessive gestational weight gain (GWG) have been shown to increase the risk of adverse pregnancy outcomes, but the risk profiles of GWG rate are unclear. We aimed to examine the associations between GWG rate in the second/third trimester and a spectrum of pregnancy outcomes. This study consisted of 14 219 Chinese rural nulliparous women who participated in a randomised controlled trial of prenatal micronutrient supplementation during 2006-2009. The outcomes included stillbirth, neonatal and infant death, preterm birth, macrosomia, low birth weight (LBW) and large and small for gestational age (LGA and SGA, respectively). GWG rate was divided into quintiles within each BMI category. Compared with women in the middle quintile, those in the lowest quintile had higher risks of neonatal death (adjusted OR 2 center dot 27; 95 % CI 1 center dot 03, 5 center dot 02), infant death (adjusted OR 1 center dot 85; 95 % CI 1 center dot 02, 3 center dot 37) and early preterm birth (adjusted OR 2 center dot 33; 95 % CI 1 center dot 13, 4 center dot 77), while those in the highest quintile had higher risks of overall preterm birth (adjusted OR 1 center dot 28; 95 % CI 1 center dot 04, 1 center dot 59), late preterm birth (adjusted OR 1 center dot 25; 95 % CI 1 center dot 00, 1 center dot 56), LBW (adjusted OR 1 center dot 48; 95 % CI 1 center dot 02, 2 center dot 15), macrosomia (adjusted OR 1 center dot 89; 95 % CI 1 center dot 46, 2 center dot 45) and LGA (adjusted OR 1 center dot 56; 95 % CI 1 center dot 31, 1 center dot 85). In conclusion, very low and very high GWG rates in the second/third trimester appear to be associated with adverse pregnancy outcomes in Chinese nulliparous women, indicating that an appropriate GWG rate during pregnancy is necessary for neonatal health.