Diabetes during pregnancy: Keeping up with the latest recommendations

New findings have changed the recommendations for the care of diabetes during pregnancy, one of the most common pregnancy complications. Dr. Mark Turrentine, professor of obstetrics and gynecology at Baylor College of Medicine, breaks down the basics of this complex condition and what you need to know today about the diagnosis and treatment of these high-risk pregnancies.

Q: What are the different types of diabetes during pregnancy?

A: There are two kinds of diabetes during pregnancy: gestational and pre-gestational diabetes.

Gestational diabetes occurs when a woman develops diabetes for the first time during pregnancy.Gestational diabetes mellitus, or GDM, is one of the most common medical complications of pregnancy.

Typically, between 6 to 9 percent of pregnant women will develop gestational diabetes.

A much smaller proportion, around 1 percent, will have what we call pre-gestational or pre-existing diabetes, meaning the woman had diabetes prior to pregnancy, either type 1 or type 2.

Q: What are the risks to mother and baby in pregnancies with diabetes?

A: Whether you have gestational or pre-gestational diabetes, if it’s untreated or poorly controlled during pregnancy, it can lead to serious complications.

Risks to mother and baby include:

• High blood pressure and preeclampsia.
• Preterm delivery.
• Large-for-gestational-age infants (macrosomia), requiring a cesarean delivery to avoid vaginal injury during birth.
• Hyperbilirubinemia (excess bilirubin in the baby’s blood).
• Shoulder dystocia and nerve injuries to large babies during delivery.
• Low glucose levels in the newborn (hypoglycemia).
• Birth defects.
• Increased risk of developing type 2 diabetes later in life for the mother and baby.

We have good evidence today, particularly with gestational diabetes, that lifestyle interventions, medications and post-monitoring can tremendously improve these outcomes.

Q: How is gestational diabetes diagnosed?

A: In the U.S., all pregnant women without a history of diabetes are screened for gestational diabetes between 24 and 28 weeks of pregnancy, typically with a 1-hour glucose challenge test. The patient drinks a sugary drink and an hour later, a blood sample is drawn and tested.

For those above the normal blood sugar level, a fasting 3-hour glucose tolerance test is recommended.

Q:  How is gestational diabetes treated?

A: Management typically starts with dietary and lifestyle changes, such as watching carbohydrate intake and increasing physical exercise, as well as monitoring glucose levels before and after meals. If those measures don’t reduce the risks to mom and baby, we start medical management, preferably insulin.

Q:  How is pre-gestational diabetes diagnosed?

A:   In 2024, the American College of Obstetricians and Gynecologists (ACOG) updated its guidance on screening for pre-gestational diabetes.

If you have a history of diabetes or risk factors such as obesity or a strong family history of diabetes, a diagnostic screening is now recommended at the get-go, during your initial prenatal visit.

It’s typically a 2-hour oral glucose tolerance test that requires fasting. Another option that doesn’t require fasting at the first prenatal visit is a hemoglobin A1c test (HbA1c), which measures your average blood glucose over two to three months.

Q: How is pre-gestational diabetes treated during pregnancy?

A: If pre-gestational diabetes is diagnosed, the same dietary and lifestyle interventions are recommended as with gestational diabetes, unless the patient is already on medication. When medications are necessary, insulin is recommended as the first-line treatment, along with close monitoring and regular prenatal visits.

Q: What happens after pregnancy if I had gestational diabetes?

A: Women with gestational diabetes are at risk of developing type 2 diabetes after pregnancy, making postpartum screening critically important. A missed diagnosis of type 2 diabetes has serious long-term implications, not only for the diabetes but also for cardiovascular disease and other health issues associated with diabetes.

Historically, we recommended women with gestational diabetes return 4 to 12 weeks after pregnancy for a follow-up diabetes screening. But compliance was low. Today, thanks to studies that have found the mother’s physiology returns to normal two to five days after birth, ACOG now recommends that patients with gestational diabetes be offered diabetes testing either before leaving the hospital after delivery or at the 4- to 12-week screening visit.

We found that this updated guidance not only enhanced overall completion rates of postpartum screening but also addresses the universal barriers to postpartum screening.

By Sharon Dearman, writer in the Department of Obstetrics and Gynecology