Key takeaways

Expectant mothers can develop late-onset gestational diabetes even after initially passing glucose tests, leading to potential complications for their newborns, such as hypoglycemia and jaundice.
Gestational diabetes occurs when the body can’t use insulin the way it should during pregnancy because of hormones produced by the placenta. It can cause problems in the baby such as high birth weight and health problems later in life.
Risk factors for developing gestational diabetes include being overweight, older than 25, having a family history of diabetes, and belonging to certain ethnic backgrounds.
Management of gestational diabetes involves lifestyle changes like maintaining a healthy BMI before conception, moderate exercise, a balanced diet, and possibly medication to control blood sugar levels.

Like many pregnant women, I dreaded my glucose test. Taken between week 24 and week 28 of pregnancy, the customary glucose test is a one- or two-part evaluation to make sure your body can break down glucose effectively. It involves drinking a syrupy sweet solution, then having your blood drawn to measure your blood sugar response. If you test high on the initial glucose screening, there is a longer follow-up glucose tolerance test.

To my relief, my glucose tolerance results came back on the high-end, but still within the normal range. My OB-GYN and I briefly discussed my numbers, and she wasn’t concerned about the results. I was expecting twins, and I was happy not to add gestational diabetes to the long list of health conditions I was already experiencing. I went home relieved, oblivious that late-onset gestational diabetes could still develop.

What is gestational diabetes?

Gestational diabetes occurs when a woman’s body can’t use insulin the way it should during pregnancy because of hormones produced by your placenta. This causes a rise in maternal blood sugars and puts their babies at risk for problems after birth, including:

High birth weight (9 pounds or more), which can make a vaginal delivery more difficult
Premature birth, which can cause breathing problems and jaundice (when the skin yellows due to too much bilirubin and decreased liver functioning)
Transient low blood sugar in the newborn
Type 2 diabetes later in life
Cardiomyopathy, a condition where the heart muscle is weak which decreases the amount of blood pumping to the vital organs

My missed late-onset gestational diabetes diagnosis

My two babies—a boy and a girl—were born at 37 weeks. After birth, my son had difficulty waking up to feed and then would fall asleep mid-feeding. My husband pointed out that our newborn was more jittery than our daughter. The nurses confirmed my concerns and tested his blood sugar. The blood sugar was very low.

“The reason babies get hypoglycemia (low blood sugar) is that the mother has high glucose levels in pregnancy,” says Susan Landers, MD, a neonatologist and author of So Many Babies. “The baby therefore, in utero, has high glucose levels, and he makes more insulin in his pancreas. So when he is born and your high blood sugar doesn’t come to him anymore, his insulin makes his blood sugar go down low.”

The pediatricians kept asking if I had been diagnosed with gestational diabetes. Eventually, doctors determined that my son needed special care and he was sent to the neonatal intensive care unit. In the NICU, the doctors asked again: “Were you diagnosed with gestational diabetes?” My answer was still no. Because of my son’s continued needs for glucose supplementation, the doctors concluded that I must have developed late-onset gestational diabetes, which went undiagnosed.

My baby spent eight full days in the NICU: His blood sugar levels were monitored and he was given an intravenous glucose solution until he was able to maintain his own blood sugars with routine feedings. He was also treated for jaundice with special light therapy, which is common in babies born to mothers with gestational diabetes.

Diagnosing gestational diabetes

In the U.S., gestational diabetes is quite common—6% to 9% of pregnant women develop the condition. Pregnant women routinely undergo testing at the beginning of the third trimester. Some women are more likely to develop the condition and may require additional testing (this would be in addition to the glucose screenings I underwent).

According to the U.S. Centers for Disease Control and Prevention (CDC) you are at higher risk if you:

Are overweight (a BMI more than 25)
Are over 25 years old
Have family members with diabetes
Are Hispanic, African American, Native American or of East Asian descent
Have previously given birth to a large baby
Have PCOS (polycystic ovarian syndrome)

I met several of the risk criteria. What I didn’t know during my pregnancy is that some women develop late-onset gestational diabetes and aren’t diagnosed until repeat third trimester testing. In the majority of cases, there are no warning signs of gestational diabetes—even late-onset diabetes. Rarely women, however, do experience excessive thirst and frequent urination.

“Anyone who is of an advanced maternal age should ask for a gestational diabetes screening, then ask for a second screening,” Dr. Landers recommends.

There is no current recommendation for a third screening, but a recent article in the Journal of Obstetrics & Gynecology suggests that guidelines may change. The medical community has identified that a need exists for additional tests later in pregnancy for those with risk factors. I’m hopeful that in the future, protocols will change. Patients can be their own best advocates and request further testing from their provider.

Treating gestational diabetes

Gestational diabetes can be avoided by maintaining a normal BMI (20-25) before conception. Pregnant women can also perform moderate exercise of 30 minutes daily, avoid simple carbohydrates, and gain less than 25 pounds during the pregnancy. Lifestyle changes help regulate blood sugar. If your blood sugar levels are even a little elevated during pregnancy, you are more at risk for pregnancy complications. In addition to avoiding high-sugar items (soft drinks, fruit juices, and pastries), add healthier items to your diet, like:

Several servings of whole fruits and veggies
Lean proteins and healthy fats in moderation
Whole grains in moderation, such as bread, cereal, pasta, and rice, as well as starchy vegetables like corn and peas

If you are diagnosed with gestational diabetes, treat it with daily blood sugar checks, exercise, proper nutrition, and medication. When diagnosed and well-controlled you and your baby can stay healthy.