Influence factors of body mass index before pregnancy and the relationship with gestational weight gain,maternal and infants complications / 中华围产医学杂志

ABSTRACT

Objective To explore the prevalence and the relative factors of the overweight and the obese in a population of Gansu Province pre-pregnancy women.and the effects of pre-pregnancy maternal body mass index (BMI) on gestational weight gain and pregnant outcome.Methods We conducted a populationbased birth cohort study in Gansu Province Maternity and Child Health Care Hospital from February,2010 to December,2011.Single live term birth women who have complete anthropometry were enrolled this study.They were categorized into four BMI groups according to World Health Organization's BMI recommendations for Asian populations.We explored the prevalence and the relative factors of the overweight and the obese,and the effects of pre-pregnancy maternal body mass index on gestational weight gain and birth outcomes by Chi-square test,analysis of variance.Results A total of 6 400 cases included in this study.The BMI range is from 13.3 to 38.1,the average BMI is (20.6 ±2.7).Among 6 400 cases,636 cases(9.9％) and 416 cases (6.5％) were overweight and obese.The average age (unityears) is increase gradually in low weight group (27.8±3.8),normal group (29.1 ±4.3),overweight group (30.3 ±4.7) and obese group (30.6±4.6),the difference was statistically significant (F=77.490,P＜0.01).The result prompt that the median BMI increased with the increasing of maternal age (r=0.18,P＜0.01).The BMI of multiparous women (21.22 ±2.63) is higher than nulliparous women (20.43 ± 2.64),the difference was statistically significant (t=-9.630,P＜0.01).The BMI has negatively correlated with education level and economic income level (r=-0.06,P＜0.01; r=-0.04,P=0.036).With the increase of BMI,the weight gain of early (13 weeks) pregnancy (F=8.892,P＜ 0.01) and the total weight gain during whole pregnancy (F=21.700,P＜ 0.01) gradually reduced in four groups.The neonatal birth weight in overweight group is largest,in turn higher than obesity group,normal group and low weight group,the difference was statistically significant (F=11.261,P＜0.01).With increasing BMI,the incidence of pre eclampsia (x2=85.758,P＜0.05),gestational diabetes mellitus (x2=58.913,P＜0.05),postpartum hemorrhage (x2=13.501,P＜0.05),neonatal hypoglycemia (x2=6.563,P＜0.05) and neonatal pulmonary hyaline membrane (x2=9.579,P＜0.05) was increased.The incidence of caesarean section (x2=125.442,P＜0.05),macrosomia (x2=62.963,P＜0.05) and birth defects (x2=9.087,P＜0.05) also increased.The incidence of abnormal umbilical cord in overweight group is highest,in turn higher than normal group,low weight group,and the obesity group (x2=15.82g,P=0.001).The incidence of neonatal electrolyte disorder in obesity group was higher than low weight group,normal group,and the overweight group (x2=12.092,P=0.007).The incidence of preterm birth in overweight group is highest,in turn higher than obesity group,normal group and the low weight group (x2=7.865,P=0.049).Compared with the normal group,the risk of caesarean section (OR=l.700,95％ CI1.325-2.181),pre-eclampsia (OR=2.436,95％ CI1.578-3.761),gestational diabetes (OR=3.182,95％ CI1.049-9.653) and abnormal umbilical cord (OR=2.252,95％ CI1.267-4.004) in overweight group was increased.the risk of pre eclampsia (OR=2.585,95％ CI1.020-6.914),macrosomia (OR=2.484,95％ CI1.017 6.070),neonatal electrolyte disorder (OR=4.430,95％ CI1.290-t5.217) in obesity group was increased.Conclusions The median BMI before pregnancy increased with increasing maternal age,parity,but decreased with education level and income level.The weight gain of early (13 weeks) pregnancy and the total weight gain during whole pregnancy decreased with increasing BMI.Overweight and obesity before pregnancy increased the risk the caesarean section,preeclampsia,gestational diabetes,macrosomia and neonatal electrolyte disorder.