[Weight gain rate in the first and second trimesters and risk of gestational diabetes:a prospective cohort study]

To investigate the relationship between the rate of weight gain in the first and second trimesters and gestational diabetes mellitus(GDM).

A total of 1189 maternal cases were included at baseline from May to September 2019 when they first came to the Maternal and Child Health Hospital in Ma'anshan for delivery and establishment of maternal health handbook(≤14 weeks+6). A total of 968 maternal cases were included in the final analysis, including 289 cases of GDM. Information on maternal socio-demographic characteristics, past history and lifestyle was collected through questionnaires. Oral glucose tolerance test was performed to screen for GDM at 24-28 weeks of pregnancy. Multi-factor logistic regression was used to analyze the relationship between the rate of weight gain in the first and second trimesters and GDM.

After adjusting for pre-pregnancy BMI, age, occupation, number of births, number of pregnancies, type of residence, family history of diabetes, season of conception and mode of conception, an increased risk of GDM was found for rapid weight gain in early pregnancy compared with appropriate rate of gain(rapid group: aOR=1.92, 95%CI 1.20-3.07). No risk of GDM was found for rapid or slow weight gain in mid-pregnancy(rapid group : aOR=0.89, 95%CI 0.47-1.70)(slow group: aOR=1.57, 95%CI 0.85-2.90). Further stratified by pre-pregnancy BMI, pre-pregnancy BMI <24-overly rapid growth rate in early pregnancy was a risk factor for GDM(rapid group; aOR=1.98, 95%CI 1.16-3.38) and no significant association was observed in pregnant women with pre-pregnancy BMI ≥24(slow group: aOR=0.79, 95%CI 0.29-2.12; rapid group: aOR=1.61, 95%CI 0.60-4.30). A multiplicative model showing no interaction between pre-pregnancy BMI and early pregnancy weight gain rate for GDM.

Excessive growth rate in the first pregnancy can affect the risk of GDM.