Medically reviewed by Dr. Connie Newman.
Angie Buchanan, 37, was thrilled with how smoothly she was sailing through her first pregnancy. "I had no morning sickness, my energy level was good and I had just determined pretzel bites were going to be the answer to my carb cravings," said Buchanan in an email.
Then, after a routine test, she got a call from her OB-GYN that knocked the wind out of her sails: Buchanan had gestational diabetes, which is diabetes diagnosed for the first time during pregnancy (gestation). It happens because the body cannot make enough insulin to control blood sugar levels. This leads to high blood sugar that can negatively affect the health of both mom and baby.
The cause of gestational diabetes is unknown, but it likely has to do with the interaction between pregnancy hormones and insulin levels. Up to 10% of pregnancies in the United States are affected by gestational diabetes every year.
Health conditions including obesity, polycystic ovary syndrome (PCOS) and high blood pressure can all increase one's risk of developing gestational diabetes, as can a lack of physical activity, having an immediate family member with diabetes and a history of heart disease.
Women who are Asian American, Black, Hispanic and Native American are also at greater risk. Although it's unclear why race and ethnicity play a role in gestational diabetes development, evidence suggests it could be due to factors like body composition, lifestyle and genetics.
Because gestational diabetes is so common, all pregnant women are routinely screened for it during their second trimester, typically between 24 and 28 weeks of pregnancy. If a woman is in a high-risk group, she may be tested earlier in her pregnancy.
Screening for gestational diabetes, called a glucose tolerance test, can be done using two different methods. With the one-step strategy, you drink a sweet sugar solution after an overnight fast, and blood is then taken at three intervals. Gestational diabetes is diagnosed when at least one glucose level exceeds set values at each interval.
In the second method, blood is taken one hour after you drink a sweet sugar solution. If the plasma glucose level is at a certain level, you undergo another test.
In this follow-up test, you have your blood taken while fasting, and then you drink an even sweeter glucose solution and have blood taken again after one, two and three hours. The diagnosis of gestational diabetes is made if two of the four glucose levels fit certain criteria.
Effects on mother and baby
If untreated, gestational diabetes can pose health risks for the mother and her fetus. A pregnant woman with gestational diabetes whose blood sugar isn't controlled has a higher chance of needing a cesarean section (C-section). She is also more likely to develop preeclampsia, dangerously high blood pressure during pregnancy.
Additionally, the fetus may have a range of serious complications, including high blood sugar, which can cause the baby to grow very large, and possibly complicate delivery or lead to preterm birth. Conversely, a woman who is taking medication for her gestational diabetes may experience hypoglycemia, or low blood sugar. Hypoglycemia in pregnancy can cause the baby to have low blood sugar at birth.
After you've been diagnosed with gestational diabetes, you'll learn how to check and monitor your blood sugar. For some women, gestational diabetes can be controlled with a diet low in carbohydrates, natural and added sugars and starches and high in protein, as well as exercise. Others may need medication.
"I cut sugars, gave up my pretzel craving, kept up my exercise and logged my food each day," Buchanan said. "Even so, it was still very hard to manage."
Buchanan was prescribed medication that increases the release of insulin into the bloodstream. Other oral medications and/or insulin injections can also be used to control blood sugar.
Socioeconomic factors can be a barrier to treatment for some women with gestational diabetes, both during pregnancy and beyond. Women in lower income brackets might have to wait longer for appointments and may face barriers to postpartum follow-up care that include cost, lack of child care, or an inability to take time away from work.
Long-term health risks
Unfortunately, the effects of gestational diabetes on a woman's health don't end after her baby is born.
"Children born to mothers with gestational diabetes have a higher risk of obesity and of diabetes when they are adults," said Dr. Connie Newman, adjunct professor of medicine at NYU Grossman School of Medicine and a member of HealthyWomen's Women's Health Advisory Council.
A 2019 meta-analysis of people with blood sugar levels considered prediabetic found lifestyle modifications including improved diet and physical activity reduced the risk of Type 2 diabetes by 47%.
Buchanan understands the importance of these lifestyle modifications. Though she ate a good diet and exercised, when her son was four, Buchanan began to see the effects of gestational diabetes on her blood sugar.
"Currently, my levels are prediabetic," she said. So she's making choices aimed at keeping her blood sugar under control, just as she did during pregnancy.
"Once again I'm tweaking my diet, maintaining an exercise routine and watching my weight," Buchanan said, "which is probably best in the long run anyway."