Diabetes and Fertility

It took two years before April and her husband felt ready to try again. With blood sugar levels near normal, she was able to conceive, though the resulting pregnancy was considered high risk. “I was monitored heavily, heavily, heavily,” she remembers. “I was on insulin and I had more sonograms and check-ups than the normal person has. But I had a healthy, nine-pound, seven-ounce baby boy.”

Diabetes is not a threat to fertility in the usual way. It most likely won’t prevent conception, unless the disease is way out of control. What happens instead is that high glucose levels in a woman’s system can damage embryonic cells, causing an early miscarriage. If a woman doesn’t know she has diabetes, or she’s managing her diabetes poorly, she’s at risk for recurrent miscarriages. Her body may spontaneously abort the developing embryo just days after conception, before a period has even been missed, leading some women with diabetes to believe they’re having trouble conceiving and are having fertility problems. “That’s a fairly common thing, that many women can be having miscarriages without knowing they’ve had one. High blood sugar impairs the ability of the fetus to implant in the uterus,” explains Robert Rizza, M.D., professor of endocrinology at the Mayo Clinic College of Medicine in Rochester, Minnesota, and president of the American Diabetes Association.

What Goes Wrong

More than 200,000 new cases of diabetes are diagnosed in the U.S. each year among women and men age 20 to 39—and roughly one-third of those who have diabetes don’t know it. It’s estimated that 2.4 percent of Americans age 20 to 39 have the disease. In the past, most women of childbearing age had type 1 diabetes, previously known as juvenile diabetes since it’s usually diagnosed in childhood. In type 1, the immune system malfunctions, causing it to destroy the insulin-producing cells of the pancreas. Since the body produces no insulin at all, women must use injections to control blood sugar levels.

Now, more and more younger people are being told they have type 2 diabetes, which used to appear mostly in middle age and is related to lifestyle factors like diet and exercise. “The epidemic of obesity is leading to more cases in women in their twenties and thirties,” says Dr. Rizza. As women have delayed childbearing and the weight of the population has increased, physicians are reporting more mothers-to-be with the disease.

With type 2 diabetes, the pancreas does produce some insulin. However, it’s either not enough, or the body is unable to use it properly, so glucose builds up in the blood. It’s usually treated with oral medications and dietary changes, though a type 2 woman who wants to get pregnant will very likely be switched from pills to insulin and kept on it throughout pregnancy. “There is currently no data on the safety of any oral agent used in pre-existing type 2 diabetes during pregnancy,” says Florence Brown, M.D., an endocrinologist at the Joslin Diabetes Center of Harvard Medical School.

Miscarriage rates among women with poorly controlled diabetes can be as high as 30 to 60 percent during that crucial first trimester of pregnancy. The risk of birth defects is also high, and also stems from uncontrolled blood sugar levels around the time of conception. “Women don’t know they are pregnant until about six weeks after their last menstrual period; by that time, many of the [baby’s] organs are already formed,” explains Dr. Brown.