Prolonged Vaginal Progesterone Use Linked to Higher Gestational Diabetes Risk: Study Shows
Turkey: Researchers have found in a new study that the use of vaginal progesterone may increase the risk of gestational diabetes, especially with longer duration and early initiation in pregnancy, suggesting the need for repeat glucose tolerance testing beyond 24–28 weeks.
The research, published in the Revista da Associação Médica Brasileira, explored whether progesterone prescribed to prevent spontaneous preterm birth could influence the development of gestational diabetes mellitus (GDM). Led by Dr. Ayşe Rabia Kanbak of Bakırçay University’s Gynecology and Obstetrics Clinic in İzmir, Turkey, the team conducted a large cross-sectional analysis to clarify this potential association.
The investigators reviewed data from 3,066 pregnant women aged 18–39 years who underwent a standard 2-hour, 75-gram oral glucose tolerance test (OGTT) between 24 and 28 weeks of gestation. Of these participants, 418 were diagnosed with GDM based on at least one abnormal plasma glucose reading, while 2,648 women with normal glucose levels served as the control group. The two groups were evaluated for factors such as maternal age, parity, pre-pregnancy body mass index, smoking status, gestational age, and use of vaginal progesterone.
The key findings of the study were as follows:
- Vaginal progesterone use was more frequent in the gestational diabetes group than in the control group (22% vs. 16%).
- Women who developed gestational diabetes received progesterone for a longer period, averaging nearly 60 days compared with about 52 days in those without the condition.
- The duration of treatment ranged from 28 to 90 days.
- Earlier initiation of progesterone appeared to increase further the risk of developing gestational diabetes.
According to the authors, these findings highlight the need for additional vigilance in women prescribed prolonged vaginal progesterone therapy. They recommend that clinicians consider repeating the OGTT after the routine 24–28 week window for patients who begin progesterone early in pregnancy or require extended treatment.
The study’s retrospective design and limited follow-up introduce some caution. Because many patients were ultimately transferred to other hospitals, obtaining complete outcome data was challenging, and the authors note that larger, randomized controlled trials are necessary to confirm their observations and inform clinical protocols.
Despite these limitations, the results point toward a clinically significant relationship between vaginal progesterone and gestational diabetes. As progesterone supplementation remains an important tool for preventing spontaneous preterm birth, the researchers stress that careful glucose monitoring—especially with longer treatment courses—could help reduce potential complications for both mother and baby.
"The study indicates that vaginal progesterone use may raise the risk of gestational diabetes, with longer and earlier treatment further increasing this risk. Patients on prolonged therapy may benefit from an additional oral glucose tolerance test after the routine 24–28-week screening," the authors concluded.
Reference: https://doi.org/10.1590/1806-9282.20250444
Next Story