According to Gram Research analysis, women with gestational diabetes are significantly more likely to have specific vaginal bacteria—Candida albicans in 27.7% versus 5.7% of healthy pregnant women, and Streptococcus agalactiae in 23.4% versus 0%. A cross-sectional study of 100 pregnant women also found that those with gestational diabetes had higher body mass, more muscle mass, and were less likely to take folic acid or probiotic supplements before pregnancy, suggesting connections between bacterial colonization, body composition, and metabolic health during pregnancy.
Researchers studied 100 pregnant women to understand why some develop gestational diabetes—a type of diabetes that happens during pregnancy. They discovered that women with gestational diabetes had different bacteria in their vaginas, carried more muscle mass, and had different health habits like drinking more coffee before pregnancy. The study also found these women were less likely to take folic acid or probiotic supplements. While these findings are interesting, the researchers caution that this is just one snapshot in time, so we can’t yet say whether the bacteria causes the diabetes or if something else is happening.
Key Statistics
A 2026 cross-sectional study of 100 pregnant women found that Candida albicans was present in 27.7% of women with gestational diabetes compared to only 5.7% of healthy pregnant women.
According to research reviewed by Gram, Streptococcus agalactiae was detected in 23.4% of pregnant women with gestational diabetes but in none of the 53 healthy pregnant women in the study.
A 2026 study of 100 pregnant women showed that women with gestational diabetes were significantly less likely to use folic acid supplements before pregnancy compared to healthy controls.
Research from a 2026 analysis of 100 pregnant women found that women with gestational diabetes had significantly higher body mass index, greater lean tissue mass, and increased total body water compared to healthy pregnant women.
The Quick Take
- What they studied: Whether the types of bacteria living in a pregnant woman’s vagina are connected to gestational diabetes, and how body composition and lifestyle habits play a role.
- Who participated: 100 pregnant women from a hospital in Poland: 47 with gestational diabetes and 53 without it. Researchers measured their weight, body composition using a special scale, and tested their vaginal bacteria.
- Key finding: Women with gestational diabetes were much more likely to have two specific types of bacteria (Candida albicans and Streptococcus agalactiae) compared to healthy pregnant women—about 28% versus 6% for one type, and 23% versus 0% for the other.
- What it means for you: This research suggests that vaginal bacteria might be connected to gestational diabetes risk, but it’s too early to say for certain. If you’re pregnant or planning to be, talk to your doctor about maintaining healthy bacteria balance and taking recommended supplements like folic acid.
The Research Details
This was a cross-sectional study, which means researchers took a snapshot of 100 pregnant women at one point in time and compared those with gestational diabetes to those without it. They measured three main things: body composition using bioelectrical impedance analysis (a special scale that measures water, muscle, and fat), vaginal bacteria using laboratory cultures (growing bacteria in dishes to identify what’s present), and lifestyle factors through questionnaires about diet, exercise, and supplement use.
The researchers carefully measured each woman’s height, weight, and body water content. They also swabbed the vagina to identify specific bacteria species. Finally, they asked detailed questions about what women ate, how much they exercised, whether they drank alcohol or coffee, and which supplements they took before and during pregnancy.
This approach allowed researchers to see patterns and associations between these different factors in women with and without gestational diabetes, though it couldn’t prove that one thing caused another.
Understanding connections between vaginal bacteria, body composition, and gestational diabetes is important because gestational diabetes affects about 2-10% of pregnancies and can cause complications for both mother and baby. If bacteria play a role, doctors might be able to prevent or manage the condition by helping women maintain healthy vaginal bacteria through probiotics or other interventions. This study provides clues for future research.
This study has some strengths: it used laboratory culture methods to identify specific bacteria (more reliable than some other methods), measured body composition precisely, and compared women with and without gestational diabetes. However, the study is relatively small (100 women) and only looks at one moment in time. The researchers themselves note that with so many comparisons, some findings might be false alarms. The cross-sectional design means we can’t tell if the bacteria causes diabetes or if diabetes causes changes in bacteria.
What the Results Show
Women with gestational diabetes had significantly different body composition compared to healthy pregnant women. They had higher BMI (body mass index), more lean tissue mass, more body cell mass, and more total body water and extracellular water. These differences were all statistically significant, meaning they’re unlikely to be due to chance.
The most striking finding involved vaginal bacteria. Candida albicans (a yeast-like organism) was found in 27.7% of women with gestational diabetes but only 5.7% of healthy women. Streptococcus agalactiae (a type of bacteria) was found in 23.4% of women with gestational diabetes but in none of the healthy women. These differences were dramatic and suggest a strong association.
Women with gestational diabetes also reported different lifestyle habits. They were more likely to have consumed alcohol and coffee before pregnancy. Importantly, they were less likely to use folic acid supplements (a vitamin that protects fetal development) or probiotic supplements (which support healthy bacteria).
The study found that dietary habits and supplement use differed between groups. Women with gestational diabetes reported less frequent use of folic acid and probiotic supplements before pregnancy, which could be important since these supplements may help prevent complications. The higher prevalence of specific bacteria in the gestational diabetes group suggests that metabolic changes during pregnancy might create an environment where certain bacteria thrive, or that these bacteria might contribute to metabolic problems.
Previous research has suggested that vaginal microbiota (the community of bacteria living in the vagina) may influence metabolic health and pregnancy outcomes. This study adds to that evidence by showing specific bacteria are more common in gestational diabetes. However, most previous studies have used genetic sequencing rather than culture methods, so direct comparisons are limited. The findings align with research showing that body composition and metabolic status influence both diabetes risk and microbial communities.
The researchers identified several important limitations. First, this is a cross-sectional study, meaning it’s like taking a photograph rather than a video—we see associations but can’t prove cause and effect. Second, the sample size is relatively small (100 women), which limits how much we can generalize to all pregnant women. Third, because the researchers made many statistical comparisons, some findings might be false positives (type I errors). Fourth, the study only looked at two specific bacteria species, not the entire bacterial community. Finally, the study was conducted in Poland, so results might differ in other populations with different genetics and environments.
The Bottom Line
Based on this research, pregnant women should: (1) Take folic acid supplements as recommended by their doctor—this study found women with gestational diabetes were less likely to use them; (2) Consider discussing probiotics with their healthcare provider, as these may support healthy vaginal bacteria; (3) Maintain a healthy weight before and during pregnancy, as body composition appears connected to gestational diabetes risk; (4) Limit alcohol and coffee consumption, especially before pregnancy. These recommendations have moderate confidence because the study shows associations but not definitive cause-and-effect relationships.
This research is most relevant to pregnant women, women planning pregnancy, and their healthcare providers. It’s especially important for women with risk factors for gestational diabetes (family history, overweight, previous gestational diabetes, or age over 35). Healthcare providers should use this as one piece of evidence when counseling women about pregnancy health. However, this single study shouldn’t change clinical practice yet—more research is needed.
If women implement these recommendations (taking supplements, maintaining healthy weight, limiting alcohol), they might see improvements in metabolic markers within weeks to months. However, gestational diabetes typically develops during the second or third trimester, so prevention efforts should start before pregnancy or very early in pregnancy. Benefits would likely be measured through blood sugar tests during routine pregnancy screening.
Frequently Asked Questions
Can vaginal bacteria cause gestational diabetes during pregnancy?
This study found associations between specific bacteria and gestational diabetes, but cannot prove bacteria causes it. The cross-sectional design only captures one moment in time. Future research tracking women throughout pregnancy is needed to determine if bacteria contribute to diabetes development or if diabetes changes the bacterial environment.
Should pregnant women take probiotic supplements to prevent gestational diabetes?
This study found women with gestational diabetes used fewer probiotics, but doesn’t prove probiotics prevent it. Talk to your doctor before starting any supplements. Folic acid is definitely recommended for all pregnant women. More research is needed to confirm whether probiotics specifically help prevent gestational diabetes.
Does body composition affect gestational diabetes risk?
This study found women with gestational diabetes had higher BMI and more muscle mass, suggesting body composition connects to diabetes risk. However, this is one snapshot, not proof of cause-and-effect. Maintaining a healthy weight before and during pregnancy remains important based on broader research evidence.
Is it safe to drink coffee during pregnancy if I have gestational diabetes risk?
This study found women with gestational diabetes reported more coffee consumption before pregnancy, but doesn’t prove coffee causes it. Most experts recommend limiting caffeine to 200mg daily (about 1-2 cups) during pregnancy. Discuss your specific situation with your healthcare provider.
How reliable is this study for making pregnancy decisions?
This is a small, single-point-in-time study showing associations, not proof of cause-and-effect. The findings are interesting but preliminary. Use this information as one consideration alongside your doctor’s recommendations and broader pregnancy guidelines, not as a standalone basis for medical decisions.
Want to Apply This Research?
- Track daily supplement intake (folic acid and probiotics), weekly coffee and alcohol consumption, and monthly weight gain. Users can set reminders for supplement timing and log consumption patterns to identify trends.
- Users can set a goal to take folic acid and probiotic supplements daily, reduce coffee intake to 1-2 cups per day, and eliminate alcohol during pregnancy. The app can provide reminders and track consistency over time.
- Create a dashboard showing supplement adherence percentage, caffeine intake trends, and weight gain trajectory compared to healthy pregnancy guidelines. Users can share this data with their healthcare provider during prenatal visits to discuss gestational diabetes risk factors.
This research describes associations found in one study of 100 pregnant women and cannot establish cause-and-effect relationships. The findings are preliminary and should not replace medical advice from your healthcare provider. If you are pregnant or planning pregnancy, especially with risk factors for gestational diabetes, consult your doctor before making changes to supplements, diet, or lifestyle. Gestational diabetes requires professional medical management. This article is for educational purposes only and is not a substitute for professional medical diagnosis, treatment, or advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.