Second trimester weight gain > 7 kg increases the risk of gestational diabetes after normal first trimester screening

The objective of this study was to determine the relationship between second trimester weight gain and the risk of gestational diabetes (GDM) after normal first trimester screening.

A total of 195 women at risk for GDM who had normal first trimester screening results were enrolled. The study group consisted of 65 women who had second trimester weight gain > 7 kg, while another 130 women with weight gain ≤ 7 kg served as the comparison group, matched 1:2 by pre-pregnancy body mass index. GDM screening was repeated during 24-28 weeks of gestation and the incidence of GDM was compared between the groups. Other possible associated factors were evaluated.

Mean age, pre-pregnancy body mass index, parity, GDM risks, first trimester weight gain, timing of GDM screening and initial test results were comparable between the groups. The incidence of GDM was significantly higher in the study than in the comparison group (24.6% vs 10.8%, P = 0.012). Logistic regression analysis showed that second trimester weight gain >7 kg and an abnormal 1 oral glucose tolerance test value on first trimester screening independently increased the risk of GDM (adjusted odds ratio 2.6, 95% confidence interval 1.13-6.0, P = 0.025 and 8.36, 95% confidence interval 2.62-26.66, P < 0.001, respectively).

Second trimester weight gain > 7 kg and an abnormal 1 oral glucose tolerance test value at first screening increased the risk of GDM in at-risk women.