Gestational weight gain in dichorionic twin pregnancies / 中华围产医学杂志

ABSTRACT

Objective:To investigate the optimal gestational weight gain (GWG) in dichorionic twin pregnancies.Methods:We conducted a retrospective analysis on 755 uncomplicated dichorionic twin pregnancies delivered at Peking University Third Hospital from August 2011 to December 2019. All participants were classified into three groups according to their pre-pregnancy body mass index (BMI), including underweight (BMI<18.5 kg/m 2, n=40), normal weight (BMI=18.5-24 kg/m 2, n=509), and overweight/obese (BMI≥24 kg/m 2, n=206) groups. Gestational BMI, rate of assisted reproduction, and the velocity of GWG were compared between the three groups using analysis of variance, Chi-square test and Kruskal-Wallis test. Regression model of GWG with the increase of gestational weeks was established using random effects model combined with restricted cubic spline to evaluate the percentiles of maternal weight gain during 4-39 gestational weeks. Results:The median of total GWG in the underweight, normal weight, and overweight/obese groups were noted for 17.0 (15.0-20.5) kg, 17.0 (14.0-21.0) kg, and 15.0 (12.0-20.0) kg, respectively, which decreased with the increase of pre-pregnancy BMI ( χ 2=11.974, P=0.002). The regression model fit well with the weight gain during different gestational weeks, which revealed that the weight gain was slow before 13 weeks of gestation, and kept at a steady speed thereafter, regardless of the pre-pregnancy BMI. The median and quartile ( P25- P75) of weight gain were 17.6 (15.2-20.3) kg, 17.3 (14.7-20.2) kg, and 15.7 (12.9-18.8) kg at 37 weeks in the underweight, normal weight, and overweight/obese groups, respectively. Conclusions:GWG of twin pregnancy changes slowly in the first trimester, and increases at a constant rate after the second trimester regardless of pre-pregnant BMI. Overweight/obese pregnancies have lower GWG.