Researchers studied 1,312 pregnant women in China to understand why some women develop gestational diabetes (a type of diabetes that happens during pregnancy). They looked at three specific genes related to how the body processes folate, a B vitamin. The study found that certain versions of these genes were linked to higher diabetes risk during pregnancy. Interestingly, when women had multiple risky gene versions together, their risk was even higher than expected. This research could help doctors identify which pregnant women need extra monitoring and support to prevent or manage pregnancy diabetes.

The Quick Take

  • What they studied: Whether specific genes that control how the body uses folate (a B vitamin) affect a pregnant woman’s chances of developing gestational diabetes.
  • Who participated: 1,312 pregnant women of Chinese Han ethnicity. Researchers looked at their genes and medical information including age, weight before pregnancy, and how much folate they ate.
  • Key finding: Women with certain versions of two genes (MTHFR and MTRR) had 2-3 times higher risk of gestational diabetes. When women had risky versions of multiple genes together, their risk jumped even higher—up to 6 times greater than women without these gene versions.
  • What it means for you: If you’re of Chinese descent and planning pregnancy or are pregnant, knowing your genetic risk factors might help your doctor watch more carefully for gestational diabetes. However, genes aren’t destiny—lifestyle changes like diet and exercise still matter greatly. Talk to your doctor about your personal risk.

The Research Details

This was a retrospective cohort study, which means researchers looked back at medical records and genetic information from 1,312 pregnant women who had already given birth. They identified which women developed gestational diabetes and which didn’t, then compared their genes to see if certain gene versions were more common in the diabetes group.

The researchers tested three specific locations in genes related to folate metabolism—the process your body uses to process and use the B vitamin folate. They used a genetic testing method called allele-specific PCR to identify which version of each gene each woman had. Then they used statistical analysis to see if certain gene versions were connected to gestational diabetes risk, while accounting for other factors like age, weight, and folate intake.

This research approach is important because gestational diabetes affects many pregnant women and can cause serious health problems for both mother and baby. By understanding the genetic factors that increase risk, doctors could eventually identify high-risk women early and provide targeted prevention strategies. The study also looked at how multiple genes work together, which is more realistic than studying genes in isolation.

This study has several strengths: it included a large number of participants (1,312 women), adjusted for important factors that could affect results (age, weight, folate intake), and used proper genetic testing methods. However, the study only included Chinese Han women, so results may not apply equally to other ethnic groups. The study was retrospective, meaning it relied on past records rather than following women forward in time, which can introduce some uncertainty.

What the Results Show

Women who carried the TT version of the MTHFR C677T gene had about 1.9 times higher risk of gestational diabetes compared to women with the standard version. This means if 10 women without this gene version developed diabetes, about 19 women with this version might develop it.

The MTRR A66G gene showed even stronger effects. Women with the AG version had 2.7 times higher risk, and women with the GG version had 3.1 times higher risk of gestational diabetes. These are substantial increases in risk.

Most importantly, the study found that when women had risky versions of multiple genes together, their risk multiplied dramatically. For example, women with both the MTHFR TT version and MTRR AG version had 6 times higher risk—much more than would be expected if the genes simply added their individual risks together. This suggests the genes work together in a synergistic way to increase diabetes risk.

The study also examined interactions between the two MTHFR gene locations (C677T and A1298C). Women with risky versions of both had 2.2 times higher risk, showing that these two parts of the same gene can work together to influence diabetes risk. This demonstrates that understanding how genes interact is important for predicting real-world risk.

Previous research has suggested that folate metabolism genes might affect gestational diabetes risk, but results have been mixed and varied by population. This study is one of the larger and more detailed examinations in a Chinese population specifically. The finding of strong gene-gene interactions is particularly novel and suggests that previous studies looking at single genes may have underestimated true risk for women carrying multiple risky versions.

The study only included Chinese Han women, so we don’t know if these same gene-risk associations apply to other ethnic groups—genetic variations differ between populations. The study was retrospective, relying on past medical records, which means some information might be incomplete or inaccurate. The researchers couldn’t determine whether these genes directly cause diabetes or simply mark increased risk. Additionally, the study didn’t examine all possible genes involved in folate metabolism, so there may be other genetic factors not captured here.

The Bottom Line

If you’re of Chinese descent and planning pregnancy or currently pregnant, discuss genetic testing for these folate metabolism genes with your doctor (moderate confidence). If you carry risky versions, focus on proven prevention strategies: maintain a healthy weight, eat a balanced diet rich in folate and other nutrients, exercise regularly, and attend all prenatal appointments for diabetes screening (high confidence). These lifestyle factors remain important regardless of genetic risk.

This research is most relevant to Chinese Han women planning pregnancy or currently pregnant. Women with a family history of gestational diabetes or type 2 diabetes should especially discuss this with their doctor. However, the findings may also be relevant to other East Asian populations with similar genetic backgrounds. Women of other ethnic backgrounds should not assume these same gene-risk relationships apply to them.

Gestational diabetes typically develops in the second or third trimester of pregnancy. If you have risky genes, your increased risk would apply throughout pregnancy. Prevention efforts should ideally start before pregnancy or as early in pregnancy as possible. Benefits from lifestyle changes like improved diet and exercise can appear within weeks to months.

Want to Apply This Research?

  • If you’ve had genetic testing showing risky MTHFR or MTRR versions, track your daily folate intake (target 400-800 mcg), weight, blood sugar readings if monitored, and exercise minutes. Log these weekly to identify patterns and share with your healthcare provider.
  • Users identified as higher genetic risk should set app reminders to: eat folate-rich foods daily (leafy greens, legumes, fortified grains), maintain consistent physical activity (150 minutes moderate exercise weekly if approved by doctor), and schedule regular prenatal glucose screening appointments.
  • Create a long-term tracking dashboard showing: folate intake trends, weight trajectory, blood sugar readings (if applicable), exercise consistency, and prenatal appointment completion. Set monthly check-ins to review progress and adjust goals with healthcare provider input.

This research identifies genetic associations with gestational diabetes risk in Chinese Han women but does not diagnose or predict individual outcomes. Genes are only one factor—lifestyle, diet, exercise, and medical care are equally or more important. If you’re pregnant or planning pregnancy, consult your obstetrician or healthcare provider before making any decisions based on this research. Genetic testing should only be done under medical supervision. This information is educational and not a substitute for professional medical advice.