Gestational diabetes

What is gestational diabetes?

Pregnancy places an extra burden on nearly every part of your body, and your poor pancreas is no exception. “By the third trimester, a woman’s pancreas has to be able to produce 2½ to three times more insulin than it usually would to keep her blood sugar levels in the normal range,” says Anne Kenshole, professor emeritus of medicine and obstetrics at the University of Toronto.

In most cases, the pancreas fills that need, but for some women (estimates range from two to 10 percent), the overworked gland can’t keep up with demand, so blood sugar levels climb. This condition — high blood sugar brought on by pregnancy — is called gestational diabetes (GD). Blood sugar levels return to normal after delivery, but gestational diabetes is an early warning that the pancreas isn’t up to par: roughly 40 percent of women with the condition develop type 2 diabetes within 10 years.
Who’s most likely to get it?

While any pregnant woman can develop GD, these factors increase the risk:

• age over 25 (but especially over 35)
• family history of type 2 diabetes
• history of GD
• First Nations, East Asian, Hispanic, African or Asian descent
• overweight or obese before pregnancy
• gaining a lot of weight during pregnancy

How can you tell if you have it?

“Because gestational diabetes is mild, usually there are no symptoms,” notes Edmond Ryan, a professor of medicine at the University of Alberta in Edmonton. That means it isn’t detected unless your doctor or midwife orders a test to check your blood sugar levels between 24 and 28 weeks of pregnancy. Normally, the first step is a 50 gram screening test, which involves taking blood before and then one hour after you down a sugary drink that tastes like extra-sweet orange pop. If your blood sugar measures higher than 7.8 mmol/L (millimoles per litre), your caregiver will recommend a longer, more accurate test. While 10 to 15 percent of expectant moms “fail” the first test, only about two to four percent actually end up being diagnosed with GD, according to Kenshole.

Who should get tested?

That depends on who you ask. The Canadian Diabetes Association recommends testing all pregnant women. On the other hand, the Society of Obstetricians and Gynaecologists of Canada says there isn’t enough evidence that large screening programs benefit moms and babies, leaving caregivers to decide whether to recommend testing to all women, no women, or only those with risk factors.

Is GD harmful to moms or babies?

The higher mom’s blood sugars, the more likely it is that her baby will be a bit bigger than average, which modestly increases her chances of having a difficult birth or needing a C-section. (It’s important to note, however, that only a small minority of big babies are born to women with GD.) Elevated blood sugars also boost the odds of pre-eclampsia, a complication that may require early delivery. And babies of moms with untreated GD run a higher risk of needing to go to the nursery for problems like jaundice and low blood sugar.

How is it treated?

“Once a woman is diagnosed with gestational diabetes, she’ll be taught how to monitor her own blood sugar,” says Kenshole. Often, sticking to a healthy eating plan and getting regular exercise can keep your blood sugar levels within healthy limits. (Bonus: These lifestyle changes can also help keep type 2 diabetes at bay after your baby’s birth.) If that doesn’t do the trick, your caregiver will prescribe medication (usually insulin). Either way, the vast majority of moms with GD go on to have otherwise uncomplicated pregnancies and healthy babies.