Association of gestational weight gain with perinatal outcomes and optimal weight gain for twin pregnancies / 中华围产医学杂志

ABSTRACT

Objective To study the association of gestational weight gain (GWG) with perinatal outcomes in twin pregnant women categorized by different prepregnant body mass index (BMI) and to explore the optimal GWG.Methods A retrospective cohort study was conducted on 1 297 twin pregnancies delivered at Beijing Obstetrics and Gynecology Hospital,Capital Medical University from January 2013 to December 2016.Based on the prepregnant BMI categories defined by World Health Organization (WHO),these subjects were divided into four groups:under weight (n=154,BMI＜18.5 kg/m2),normal weight (n=890,BMI ≥ 18.5-＜ 25 kg/m2),overweight (n=209,BMI ≥ 25-＜30 kg/m2) and obese (n=44,BMI ≥ 30 kg/m2) groups.Women with BMI＜18.5 kg/m2 were excluded from the study and the rest 1 143 subjects were categorized into three groups according to the Institute of Medicine (IOM) guidelines:inadequate GWG (n=334),appropriate GWG (n=634) and excessive GWG groups (n=175).The association of maternal prepregnant BMI and GWG with maternal complications and neonatal weight were studied.Only 585 women who delivered twins weighted ≥ 2 500 g on average at ≥ 37 gestational weeks were included when exploring the optimal GWG.The P25-P75 of pregnant women with different prepregnant BMI was calculated to be the suitable range for weight gain during pregnancy.Chi-square test and multivariate logistic regression analysis were used for statistical analysis.Results (1) Compared with the normal weight group,the under weight group had an increased risk of low birth weight twins (OR=1.64,95％CI:1.16-2.31),but decreased risks of gestational diabetes mellitus (GDM) and cesarean section (OR=0.58,95％CI:0.35-0.96;OR=0.41,95％CI:0.22-0.77).The risks of preeclampsia (OR=1.64,95％CI:1.09-2.49;OR=2.63,95％CI:1.29-5.37) and GDM (OR=2.07,95％CI:1.49-2.89;OR=4.12,95％CI:2.23-7.60) increased in overweight and obese women.(2) Compared with the women with appropriate GWG,the risks of preterm delivery (OR=1.46,95％CI:1.12-1.91) and low birth weight twins (OR=2.03,95％CI:1.55～2.65) increased,while those of preeclampsia (OR=0.49,95％CI:0.31-0.79) and cesarean section (OR=0.38,95％CI:0.21-0.70) decreased in inadequate GWG women.Subgroup analysis according to prepregnant BMI showed that inadequate GWG increased the risks of preterm birth (OR=1.46,95％CI:1.08-1.97) and low birth weight twins (OR=2.22,95％CI:1.64-3.02) in the normal weight women,but decreased the risks of preeclampsia in both normal weight and overweight and obese women (OR=0.55,95％CI:0.31-0.97;OR=0.39,95％CI:0.16-0.94).Moreover,the risks of cesarean section for women with inadequate GWG were reduced in both normal weight and overweight and obese groups (OR=0.43 and 0.23,95％CI:0.22-0.85 and 0.06-0.96).Compared with the women with appropriate GWG,the risk of small for gestational age (SGA) (OR=0.63,95％CI:0.42-0.95)decreased,but the risk of preeclampsia increased (OR=1.71,95％CI:1.11-2.62) in excessive GWG women.Subgroup analysis by prepregnant BMI showed that excessive GWG decreased the risks of SGA (OR=0.10,95％CI:0.02-0.45) and low birth weight twins (OR=0.28,95％CI:0.11-0.71) in the overweight and obese group,but increased the risk of preeclampsia in the normal weight group (OR=2.08,95％CI:1.26-3.43).(3) Multivariate logistic regression analysis revealed that inadequate GWG was a risk factor for preterm birth (OR=1.44,95％CI:1.31-1.59) and low birth weight twins (OR=2.08,95％CI:1.70-2.53),but a protective factor for preeclampsia (OR=0.51,95％CI:0.32-0.82) and cesarean section (OR=0.38,95％CI:0.20-0.69).Excessive GWG reduced the risk of SGA (OR=0.61,95％CI:0.50-0.75),but increased the risk of preeclampsia (OR=1.65,95％CI:1.07-2.55).(4) The total GWG reference values (P25-P75) for twin pregnancies at term were 17-25 kg for under weight women,17-24 kg for normal weight women,14-22 kg for overweight women and 9.5-17 kg for obese women.Conclusions Adverse perinatal outcomes might be increased in either inadequate or excessive GWG in normal prepregnant weight women with twins,so IOM guidelines is recommended in GWG management in this population.The optimal total GWG reference values (P25-P75) for non-obese twin pregnancies are consistent with the IOM recommendations,but those for obese women are yet to be explored.