Gestational diabetes is a form of high blood sugar that develops during pregnancy. It most often appears between the 24th and 28th week, affecting about 7% of pregnancies in the United States, more than 200,000 women each year.
What Causes Gestational Diabetes?
During pregnancy, hormones from the placenta can make it harder for insulin to work properly. This condition, called insulin resistance, can cause blood sugar levels to rise. While most women produce extra insulin to compensate, some cannot, leading to diabetes during pregnancy.
Who’s at Risk?
Anyone can develop gestational diabetes, but the risk is higher if you:
- Are overweight or obese
- Are over age 25
- Have a family history of type 2 diabetes
- Had gestational diabetes in a previous pregnancy
- Have polycystic ovary syndrome (PCOS)
- Belong to specific ethnic groups (e.g., African American, Hispanic, Native American, South Asian)
How Is Gestational Diabetes Diagnosed?
Doctors typically screen all pregnant women between 24 and 28 weeks using a glucose tolerance test. There are two main types:
- Two-step test: Starts with a 50g glucose drink followed by a 1-hour blood test. If elevated, a longer 3-hour test follows.
- One-step test: Involves a 75g glucose drink with blood drawn at 0, 1, and 2 hours. This method is more common internationally and recommended by the ADA and WHO.
What Are the Risks?
For the Baby:
- Being born too large (macrosomia)
- Birth trauma during delivery
- Low blood sugar (hypoglycemia) after birth
- Increased risk of obesity and type 2 diabetes later in life
For the Mother:
- Higher chance of cesarean delivery
- Preeclampsia (high blood pressure and organ stress)
- Higher risk of type 2 diabetes after pregnancy
Can Gestational Diabetes Be Treated?
Yes—treatment can protect both mother and baby. The main goals are to keep blood sugar levels in a healthy range and prevent complications. Treatment includes:
- Healthy eating: A balanced, carb-controlled diet designed by a registered dietitian
- Physical activity: Walking or other moderate exercise after meals
- Blood glucose monitoring: Usually 4 times a day (fasting and after meals)
- Insulin or oral medications: If lifestyle changes aren’t enough to control glucose
How Does It Affect the Baby Long-Term?
A groundbreaking study from Kaiser Permanente and published in Diabetes Care found that untreated gestational diabetes nearly doubles a child’s risk of obesity by age 5–7. However, treating the mother’s blood sugar levels during pregnancy can reduce that risk to normal.
Researchers followed over 9,400 mother-child pairs and discovered that even mild elevations in blood sugar during pregnancy were linked to higher childhood obesity, but treatment reversed the effect.
What Happens After Delivery?
Gestational diabetes usually goes away after the baby is born. However, women who had it are at increased risk of developing type 2 diabetes later. The American Diabetes Association recommends a 75g glucose tolerance test 4–12 weeks postpartum and regular testing every 1–3 years afterward.
Key Takeaways
- Gestational diabetes affects 1 in 14 pregnancies
- Early detection and treatment help avoid complications
- Managing blood sugar during pregnancy lowers risks for mother and baby
- Women with GDM need ongoing monitoring after birth