What to Know About Gestational Diabetes

Gestational diabetes mellitus (GDM)--diabetes that can develop during pregnancy in women who don’t already have the condition--affects approximately ten percent of pregnant women.

It occurs during pregnancy when the body can’t make enough insulin, a hormone made by the pancreas that acts like a key to let blood sugar into the cells in your body for use as energy. 

The hormonal fluctuations that the body undergoes during pregnancy, which causes changes such as weight gain, can cause the body’s cells to use insulin less effectively. All pregnant women experience some insulin resistance during late pregnancy, but some have it even before they become pregnant. Their pregnancies start with a greater need for insulin and are more likely to experience gestational diabetes. 

But there’s good news, says Melissa Katz, MD, Assistant Professor of Clinical Medicine - Weill Cornell Medical College and Cornell University and Assistant Attending Physician - NewYork-Presbyterian Hospital. 

“The chances of being diagnosed with GDM can be markedly decreased by starting pregnancy at a normal weight and with a healthy diet,” Dr. Katz says. “Women should not eat an excess of carbohydrates. Having a reasonable pre-pregnancy exercise regimen is also helpful.” 

Around 70% of cases can be treated with diet modifications and exercise. 

“The mother must adjust her diet so the baby receives an appropriate amount of sugar, rather than excessive quantities,” Dr. Katz explains. “This is essential to decrease the risk of complications.” 

Those complications can include the baby being born large for their gestational age; hypoglycemia (low blood sugarat birthcongenital malformations; and pre-term delivery. 

About 30% of pregnant women may need to take insulin or other medication to lower her glucose level. 

“Its important for mothers with GDM to recognize that a normal glucose level is important, regardless of whether it is achieved with diet or medication” Dr. Katz adds. 

The consequences of poor glucose control during pregnancy can include preeclampsia (when a woman who previously had normal blood pressure suddenly develops high blood pressure and protein in her urine or other problems after 20 weeks of pregnancy); gestational hypertension; or excess amniotic fluid. 

Though testing for GDM is usually conducted around the 24th to 28th week of pregnancy, it may be done earlier if the mother is in a high-risk category, for example, if the woman has polycystic ovarian syndrome, prediabetes, and/or obesity. Also at higher risk for GDM are women with a family history of Type 2 diabetes, those are older, and those who use steroids during pregnancy. 

“Preconception counseling is essential for all women with any risk factors,” Dr. Katz says. “Pre-pregnancy weight loss and nutritional education should be encouraged for overweight or obese women.” 

For the mother, GDM usually resolves when the baby is delivered. But the condition can serve as a message about her future health and pregnancies. 

“A minority of women will remain diabetic or prediabetic,” she says. “Women with GDM have a ten-fold increased risk of developing Type 2 diabetes later in life, and are likely to have a recurrence in subsequent pregnancies. Its essential that they implement the lifestyle modifications they learned during pregnancy.” 

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