Should gestational diabetes be treated?

"You’ll find mixed opinions, very opinionated opinions, on the subject of gestational diabetes,” says Anne Kenshole, professor emeritus of medicine and obstetrics at Women’s College Hospital and the University of Toronto.

So what is this condition that has doctors debating—and where do they disagree?

Gestational diabetes—elevated blood sugar levels in late pregnancy—occurs when a woman’s body can’t meet increasing demand for the blood-sugar-regulating hormone insulin. Consequently, her blood sugar levels rise modestly—though not high enough to warrant a diagnosis of diabetes outside of pregnancy. But does that relatively slight boost in blood sugar levels cause problems—for example, increasing the likelihood of having bigger babies who are more apt to be injured during birth, or need to be delivered by C-section? And if so, does treatment (diet, exercise and, if necessary, insulin) reduce the risk?

Those are the million-dollar questions—and at least some doctors argue they haven’t been satisfactorily answered. “Some obstetricians are firmly of the opinion that gestational diabetes is a threat to the mother and child, and treat it very aggressively.” Kenshole observes. “Others, perhaps taking a more scientific view, say we just don’t know.”

In fact, when the Society of Obstetricians and Gynaecologists of Canada last reviewed the available research in 2002, they concluded there wasn’t enough evidence to support screening (which is why their current guidelines leave the choice up to a doctor): Research has yielded conflicting results. Even when treatment keeps babies from growing very large, those babies don’t seem to do any better than those of untreated moms. At least one study suggested that simply labelling women as having gestational diabetes increased the likelihood of Caesarean by nearly half (probably because doctors were worried the babies would be too large to be born vaginally)—without any apparent benefit. And while a more recent trial, released in 2005, found certain complications were more common in babies of untreated women (four percent versus one percent), at least some problems in the latter group may have been unrelated to diabetes.

Many caregivers agree on at least one thing—eating a healthy diet, limiting sugar (including fruit juice) and exercising regularly probably increase your chances of having a problem-free pregnancy, birth and a healthy baby—regardless of whether you have gestational diabetes.

While true gestational diabetes disappears after delivery, some women who are diagnosed with it (five to 10 percent according to some estimates) actually have a permanent condition called type 2 diabetes that wasn’t picked up before pregnancy. This serious disorder is linked with miscarriage and stillbirth, so if you have other risk factors (for example, if you’re overweight), you may want to have your blood sugar checked early in pregnancy, rather than waiting until 24 to 28 weeks when screening is normally done. Early diagnosis and tight blood sugar control rein in the risks.

If you’re diagnosed with gestational diabetes, it’s worth taking a serious look at your lifestyle: Approximately 20 to 50 percent of women with the condition develop type 2 within five to 10 years, and large-scale studies show regular exercise and healthy eating substantially improve the likelihood of avoiding the disease.

Originally posted in April 2007.