Gestational Diabetes: Key Risk Factors and What Happens After Birth

What Was Studied and Why It Matters

Gestational diabetes mellitus (GDM) — high blood sugar that develops during pregnancy — is one of the most common pregnancy complications worldwide. It raises the risk of problems for both mother and baby, and it can signal a higher chance of developing type 2 diabetes later in life. Researchers at Sanno Hospital in Tokyo reviewed nearly a decade of data from 11,694 pregnant women to better understand who is most at risk for GDM and, just as importantly, who is most likely to have ongoing blood sugar problems after giving birth.

What the Researchers Found

Of the 3,177 women who received a formal glucose tolerance test during pregnancy, 1,025 — roughly 1 in 3 — were diagnosed with GDM. The average age at diagnosis was 36, and most women had a healthy pre-pregnancy body weight. Key findings included:

• Pre-pregnancy weight mattered most. Having a higher body mass index (BMI) before pregnancy was a stronger predictor of GDM than age alone. When both obesity and older maternal age were present together, the risk increased dramatically.
• Family and personal history count. Women with a previous GDM diagnosis or a family history of diabetes faced significantly higher risk.
• Higher early screening scores were a warning sign. Women whose initial glucose screening test (the 50-g glucose challenge) came back elevated were more likely to develop GDM and to have blood sugar problems after delivery.
• Fertility treatment itself was not a risk factor. Undergoing infertility treatment did not independently raise GDM risk — the increased risk seen in that group was largely explained by the fact that those women tended to be older and heavier.
• Babies were affected too. GDM was linked to higher rates of large-for-gestational-age newborns and low blood sugar in newborns after birth.

What Happened After Delivery

This is where the findings get especially important for long-term health. When women returned for a follow-up glucose test 6–12 weeks after giving birth:

• 65.6% returned to normal blood sugar levels
• 31.4% had prediabetes (impaired glucose tolerance)
• 3.0% were diagnosed with type 2 diabetes

In other words, more than 1 in 3 women with GDM still had blood sugar problems weeks after delivery. Women with a family history of diabetes, a previous GDM diagnosis, or worse glucose readings during pregnancy were most likely to remain in an at-risk category.

What This Means for Real Patients

If you have been diagnosed with GDM — or are planning a pregnancy — this research carries a clear message: blood sugar monitoring should not stop at delivery. Keeping track of glucose levels after birth is critical, and managing your weight before pregnancy is one of the most powerful steps you can take to reduce risk. Reliable monitoring tools, including blood glucose meters and continuous glucose monitors, are essential throughout this journey. MDS Diabetes offers a wide range of diabetes management supplies to support women during and after pregnancy.

Bottom Line

Pre-pregnancy BMI is the single strongest controllable risk factor for gestational diabetes. One in three women with GDM will have lingering blood sugar issues after birth, making postpartum monitoring just as important as prenatal care. A team-based approach — starting before conception and continuing well after delivery — gives mothers and babies the best chance at long-term health.