Pregnancy diabetes, known medically as gestational diabetes, is a type of diabetes that develops during pregnancy in people who didn’t have diabetes before. It affects roughly 79 out of every 1,000 births in the U.S. as of 2024, a rate that has climbed 36% since 2016. The condition typically appears in the second half of pregnancy, resolves after delivery, but carries real consequences for both mother and baby if it’s not managed well.
Why Pregnancy Causes Diabetes
During pregnancy, your placenta releases hormones and inflammatory signals that make your cells less responsive to insulin, the hormone that moves sugar out of your bloodstream and into your cells. This insulin resistance is actually normal. It ensures your baby gets a steady supply of glucose for growth.
Gestational diabetes develops when your body can’t produce enough extra insulin to overcome that resistance. The placenta releases substances that block insulin’s signaling pathway inside your cells, reducing its effectiveness throughout your body. In some women, this process ramps up earlier and more aggressively, particularly when elevated levels of a hormone called leptin trigger additional inflammatory compounds in the placenta during the first trimester. The result is blood sugar that stays too high after meals, and sometimes between meals as well.
Who Is at Higher Risk
Some people are more likely to develop gestational diabetes than others. Being overweight before pregnancy, being over 25, having a family history of type 2 diabetes, or having had gestational diabetes in a previous pregnancy all raise the odds. Rates also vary significantly by race and ethnicity. In 2024, American Indian/Alaska Native women had the highest rate at 137 per 1,000 births, followed by Asian women at 131 per 1,000 and Native Hawaiian/Pacific Islander women at 126 per 1,000. Hispanic women had a rate of 85 per 1,000, White women 71, and Black women 67. These differences reflect a mix of genetic predisposition, access to care, and other health factors.
How It’s Diagnosed
Most pregnant people are screened for gestational diabetes between 24 and 28 weeks of gestation, which is when placental insulin resistance ramps up enough to reveal the problem. The most common approach in the U.S. involves two steps.
First, you drink a sugary glucose solution and have your blood drawn one hour later. If your blood sugar hits 190 mg/dL or higher, that alone points to gestational diabetes. If it’s elevated but below that threshold, you move on to a longer, three-hour test.
For the three-hour test, you fast overnight, then drink a higher-dose glucose solution. Your blood is drawn four times: once fasting and then at one, two, and three hours. The target values are: fasting at or below 95 mg/dL, one hour at or below 180 mg/dL, two hours at or below 155 mg/dL, and three hours at or below 140 mg/dL. If two or more of those readings come back high, you’ll be diagnosed with gestational diabetes.
Risks for the Baby
When your blood sugar stays elevated, your baby receives more glucose than it needs. The baby’s pancreas responds by producing extra insulin, and that excess insulin acts as a growth hormone. This can lead to a condition called macrosomia, where the baby weighs more than 8 pounds, 13 ounces. A larger baby increases the chance of a difficult delivery, shoulder injuries during birth, and a higher likelihood of needing a cesarean section.
After delivery, the baby’s pancreas may still be overproducing insulin even though the extra glucose supply from the mother has stopped. This can cause dangerously low blood sugar (hypoglycemia) in the newborn’s first hours of life. Some babies born to mothers with poorly controlled gestational diabetes also have trouble breathing shortly after birth. Both complications are typically caught and managed quickly in the hospital, but they underscore why blood sugar control during pregnancy matters.
Risks for the Mother
Gestational diabetes nearly doubles the risk of preeclampsia, a dangerous condition involving high blood pressure and organ damage during pregnancy. In one large study, 2.6% of women with gestational diabetes developed preeclampsia compared to 1.2% of women without it, representing a 90% higher risk after accounting for other factors. Preeclampsia can lead to early delivery and serious complications for both mother and baby.
The longer-term picture is significant too. About half of women who have gestational diabetes eventually develop type 2 diabetes later in life, according to the CDC. That’s not inevitable, but it means gestational diabetes is an important early warning sign that your body already struggles with insulin.
Managing Blood Sugar During Pregnancy
The first and most important step is adjusting what and how you eat. For most people with gestational diabetes, the goal is roughly 30 to 45 grams of carbohydrates per meal and 15 to 30 grams per snack. That might mean swapping a large bowl of pasta for a smaller portion alongside protein and vegetables, or replacing juice with whole fruit paired with nuts. Spreading your carbohydrate intake across three meals and two to three snacks throughout the day prevents the blood sugar spikes that come from eating too much at once.
Regular physical activity also helps. Walking for 15 to 30 minutes after meals can noticeably lower blood sugar because your muscles use glucose directly during exercise, even when insulin isn’t working well. You’ll be asked to check your blood sugar several times a day, typically first thing in the morning and after meals, using a small finger-prick monitor at home.
For many people, diet and exercise are enough. When they’re not, insulin is the first-line treatment recommended by both the American Diabetes Association and the American College of Obstetricians and Gynecologists. Insulin doesn’t cross the placenta, making it the safest medication option for the baby. Other blood sugar medications are not recommended as first-line treatment during pregnancy because they do cross the placenta and may not control blood sugar as reliably.
What Happens After Delivery
In most cases, blood sugar returns to normal shortly after the placenta is delivered, because the source of the extra insulin resistance is gone. Your care team will monitor your blood sugar in the hospital to confirm this is happening.
The recommended follow-up is a glucose tolerance test 6 to 12 weeks after delivery to make sure your blood sugar has truly normalized. This step is important and frequently skipped. If results come back normal, you’re not out of the woods permanently. Given that about half of women with gestational diabetes develop type 2 diabetes over time, getting screened for diabetes every one to three years going forward gives you the chance to catch any changes early, when lifestyle adjustments can make the biggest difference.
If you become pregnant again, you’ll likely be screened earlier than 24 weeks, since having gestational diabetes once significantly raises the chance of having it in future pregnancies.