Is the use of vaginal progesterone a factor in pregnant women diagnosed with gestational diabetes mellitus?

The aim of this study was to investigate the effect of vaginal progesterone used to prevent spontaneous preterm birth in the development of gestational diabetes mellitus.

This is a cross-sectional study that investigated pregnant women aged 18-39 years. The study participants underwent a 2-h, 75-g oral glucose tolerance test at 24 and 28 weeks of gestation. A total of 3,066 patients met the inclusion criteria, and 418 were diagnosed with gestational diabetes mellitus based on at least one abnormal plasma glucose value during screening. The remaining 2,648 patients, who had normal plasma glucose levels, were classified as the control group. The two groups were compared based on various factors, including age, parity, pre-pregnancy body mass index, smoking status, gestational age, and use of vaginal progesterone.

The use of vaginal progesterone was statistically significant at a higher rate in the gestational diabetes mellitus group compared to the control group (22.0 vs. 16.0%; p=0.002). The mean duration of vaginal progesterone use was 53.4±14.6 days (ranging from 28 to 90 days), and this duration was statistically significantly longer in the gestational diabetes mellitus group (59.9±14.8 vs. 52.0±14.2; p<0.001).

The findings suggest that the use of vaginal progesterone may increase the risk of gestational diabetes mellitus, and the risk appears to rise with the duration of progesterone use. It is important to consider that patients on prolonged vaginal progesterone, particularly those started early in pregnancy, may be at increased risk of diabetes. Therefore, it may be advisable to repeat the oral glucose tolerance test performed at 24-28 weeks in the following weeks.