Gestational Diabetes

Why Gestational Diabetes Happens

As pregnancy progresses, the placenta releases hormones that interfere with insulin's action. Most people make enough extra insulin to compensate. When the body can't, glucose builds up in the blood and gestational diabetes develops, typically around the 24th week of pregnancy.

Gestational diabetes is not caused by anything you did. Some people diagnosed during pregnancy actually had mild, undetected diabetes beforehand, which is one reason follow-up testing after birth is so important.

Gestational Diabetes Risk Factors

Anyone can develop gestational diabetes, including people with no risk factors. Your risk is higher if you:

• Had gestational diabetes in a previous pregnancy
• Previously gave birth to a baby weighing more than 9 pounds
• Have overweight or obesity
• Have a family history of type 2 diabetes or have been told you have prediabetes
• Have polycystic ovary syndrome (PCOS)
• Are of African American, Asian American, Hispanic or Latino, American Indian, Alaska Native, Native Hawaiian, or Pacific Islander descent

Screening and Diagnosis: The 24 to 28 Week Glucose Test

If you have risk factors, your care team may check your glucose early in pregnancy. When early results meet the standard diabetes thresholds, the condition is usually treated as diabetes that existed before pregnancy. Everyone else is typically tested between 24 and 28 weeks, using one of two approaches:

• One-step test: a fasting 75-gram oral glucose tolerance test. Gestational diabetes is diagnosed if any value meets or exceeds 92 mg/dL fasting, 180 mg/dL at 1 hour, or 153 mg/dL at 2 hours.
• Two-step test: a non-fasting 50-gram glucose drink with a blood test 1 hour later, followed by a longer 100-gram, 3-hour test if the first result is elevated.

Why Treating Gestational Diabetes Matters

When glucose runs high, extra sugar reaches the baby, who can grow larger than expected. A large baby (9 pounds or more) raises the chance of a difficult delivery, shoulder injury, and cesarean birth. High blood pressure and preeclampsia are also more common with gestational diabetes.

After birth, babies may have low blood sugar or breathing problems and need extra monitoring. Children born after a gestational diabetes pregnancy also have a higher risk of overweight and diabetes later in life, so let your baby's pediatrician know about your diagnosis.

Managing Gestational Diabetes: Monitoring, Nutrition, and Medication

Treatment centers on checking your glucose, typically when you wake up and after meals, and keeping it within the targets your care team sets. Commonly used targets are below 95 mg/dL fasting, and either below 140 mg/dL one hour or below 120 mg/dL two hours after a meal.

Many people reach their targets with nutrition changes and activity alone, such as three meals and two to three snacks a day and a 10- to 15-minute walk after meals. If glucose stays high, insulin is the recommended medication because it does not cross the placenta; oral medicines are sometimes used after discussing risks and benefits. The ACOG patient guide to gestational diabetes offers practical day-to-day tips.

How an Endocrinologist at TopInspired.com Works With Your OB Team

Gestational diabetes can change quickly, so timely adjustments matter. Your endocrinologist reviews your glucose log or CGM data, often between regular visits, and starts or adjusts insulin when needed. We teach injection technique, how to prevent and treat low blood sugar, and how to adapt doses as insulin needs rise later in pregnancy.

We share every plan with your obstetrician or maternal-fetal medicine specialist so everyone works from the same information, and we plan ahead for insulin changes around delivery. Virtual visits make appointments easier to fit into a busy pregnancy; contact us to arrange a consultation.

After Delivery: Protecting Your Long-Term Health

Gestational diabetes usually resolves after birth, and insulin is typically stopped. But it signals a higher lifelong risk: according to the CDC, about half of women who had gestational diabetes go on to develop type 2 diabetes.

Plan for a glucose test 4 to 12 weeks after delivery, then diabetes testing every 1 to 3 years if results are normal. Staying active, working toward a healthy weight, and planning future pregnancies with your care team can help lower your risk. Gestational diabetes can return in a later pregnancy, so early screening next time is wise.

Gestational Diabetes: frequently asked questions

Sources & further reading

• CDC: Gestational Diabetes
• ACOG: Gestational Diabetes FAQ
• NIDDK: Gestational Diabetes
• American Diabetes Association: Standards of Care in Diabetes

Last reviewed September 19, 2026. This page is educational and is not a substitute for personal medical advice — see our medical disclaimer.