Gestational weight gain rate in third trimester relates to maternal and neonatal outcomes in pregnancies with normal glucose tolerance / 中华围产医学杂志

ABSTRACT

Objective To investigate the association between third-trimester gestational weight gain rate (GWGR) and both maternal and neonatal health outcomes in a normal glucose tolerance obstetric population.Methods This was a retrospective cohort study of full-term singleton live births (n=1 967) in women with a normal oral glucose tolerance test (OGTT) tested at 24-28 gestational weeks,who gave birth at Beijing Obstetrics and Gynecology Hospital,Capital Medical University,between January and December in 2013.The subjects were divided into three groups based on third-trimester GWGR category of the 2009 Institute of Medicine (IOM) guidelines.Each group was divided into three subgroups by pre-pregnancy body mass index (BMI)low (＜18.5),normal (≥ 18.5-＜25.0),and high (≥ 25.0).One-way analysis of variance,Chi-square or Fisher's exact test,Logistic regression and corrected analysis were performed for statistical analysis.Results (1) Of the 1 967 women analyzed,third-trimester weight gain distribution was normal in 575(29.2％),excessive in 982(49.9％),and insufficient in 410(20.8％).No significant differences were found in terms of age,parity,education level,family history of diabetes or hypertension among the GWGR groups (all P＞0.05).(2) The mean third-trimester weight gain in the 1 967 normal OGTT women was (0.56±0.23) kg/week and the mean neonatal birth weight was (3 442±396) g.The above two parameters were linearly correlated (Y=103.839X+3383.752,r=0.621,P＜0.01).The excessive GWGR group had higher birth weight infants than the normal GWGR group [(3 463.1±417.3) vs (3 427.4±376.1) g,F=4.901,P=0.014].Women in the insufficient GWGR group had lower birth weight infants (3 375.1 ±370.1) g than those in the normal GWGR group (F=4.408,P=0.021).Compared to the normal GWGR group,the excessive GWGR group was associated with an increased risk of fetal macrosomia (OR=1.59,95％CI1.10-2.30) and low birth weight infants (OR=2.25,95％CI1.03-4.94),and decreased odds of normal birth weight deliveries (OR=0.81,95％CI0.77-0.95).The insufficient GWGR group was associated with an elevated risk of low birth weight infants (OR=3.21,95％CI2.56-7.51,P＜0.01),but not related to the risk of fetal macrosomia on normal birth weight deliveries (all P＞0.05).(3) Compared to the normal GWGR group,the excessive GWGR group had an increased incidence of cesarean section [30.2％ (297/982)vs 22.2％ (128/575)] and hypertensive disorders of pregnancy [4.0％ (39/982) vs 1.9％ (11/575)] (all P＜0.01).No significant differences in the risk of surgical delivery and pregnancy-related hypertension were observed in the insufficient GWGR group compared to the normal GWGR group.No significant differences in the odds of neonatal intensive care unit admission were noted among the three GWGR groups (P＞0.05).(4) In the normal and insufficient GWGR groups,no differences in neonatal birth weight or risk of small-for-gestational age (SGA)or large-for-gestational age (LGA) were seen in any of the BMI subgroups (all P＞0.05).In the excessive GWGR group,the high pre-pregnant BMI subgroup showed higher neonatal birth weight than the normal pre-pregnant BMI subgroup [(3 552.3±445.0) vs (3 481.8±416.1) g,P＜0.01],and the low pre-pregnant BMI subgroup showed lower neonatal birth weight (3 352.7 ± 371.2) g than the normal pre-pregnant BMI subgroup (P＜0.01).Moreover,the high pre-pregnant BMI subgroup in the excessive GWGR group had an increased risk of fetal macrosomia (OR=1.60,95％CI1.11-2.81).Conversely,the low pre-pregnant BMI subgroup in the excessive GWGR group had a decreased risk of fetal macrosomia (OR=0.52,95％CI0.29-0.97) (all P＜0.05).The high BMI subgroup had a greater risk of hypertensive disorders of pregnancy than the normal BMI subgroup in all GWGR groups (allP＜0.05).The incidence of surgical delivery or NICU admission was not significantly different among the three GWGR subgroups.Conclusions Excessive weight gain in third-trimester is common in normal OGTT women.Excessive gestational weight gain is associated with adverse maternal and neonatal outcomes.Thus,gestational weight gain in the third-trimester should be adequately monitored and a balance in weight gain within the range recommended by the 2009 IOM guidelines should be established in normal OGTT pregnant women.