Gestational diabetes.

With more than 65 percent of Americans overweight or obese and rates of Type 2 diabetes skyrocketing, it should come as no surprise that the incidence of gestational diabetes--a form of diabetes that occurs only in pregnancy--is also on the rise. Kaiser Permanent of Colorado, for instance, a large health care provider and health insurer, found that gestational diabetes rates doubled among its members between 1994 and 2002. (34)

Both Type 2 diabetes, the most common form of the disease, and gestational diabetes share several risk factors, including obesity, a family history of diabetes and being African-American or Hispanic. Other risk factors include having previously had a large baby and being older than 25.

Overall, estimates are that gestational diabetes affects about two to five percent of pregnant women in the U.S. Experts suspect it is related to changing hormone levels, particularly human placental lactogen, produced by the placenta. This hormone limits the effectiveness of insulin, preventing it from "unlocking" cells so glucose can enter and be transformed into energy. Usually, the pancreas overrides this resistance by pumping out more insulin; but sometimes the pancreas can't keep up, and blood glucose levels rise as gestational diabetes sets in.

Good care can prevent problems posed by gestational diabetes. A study published in the June 2005 issue of the New England Journal of Medicine found that women with gestational diabetes who received dietary advice, blood glucose monitoring and insulin therapy if needed had fewer pregnancy-related complications and a better quality of life after delivery than women with the condition who received routine obstetrical care. (31)

Most cases of gestational diabetes are treated with diet alone, but you should see a registered dietician for an individualized plan. Although you shouldn't diet when you're pregnant, if you're obese, the American Diabetes Association notes that cutting calories by a third can reduce the risk of high blood sugar and high levels of triglycerides. Other evidence suggests that limiting carbohydrates if you're obese could reduce glucose levels and the risk of problems with mother or baby. (32)

If diet isn't enough, your health care professional may recommend insulin injections or an oral diabetes medication called glyburide. A major study published in 2000 found glyburide worked well in pregnant women and did not cross the placenta, so it had no obvious ill effects on the baby. (33) Its use hasn't yet become routine, says Steven Allen, MD, an associate professor at Scott and White Hospital and Clinic at Texas A & M University in Temple, TX, but he and many other physicians frequently prescribe it.

Gestational diabetes disappears after delivery, but the risk of diabetes doesn't. Half of all women with gestational diabetes later develop Type 2 diabetes, says Dr. Allen. Diabetes persists after delivery in some women. In those cases, it's quite likely they had undiagnosed diabetes before they got pregnant, Dr. Allen says.

Reducing your risk of Type 2 diabetes is pretty basic: "Diet and exercise are key," says Dr. Allen. That means losing weight and following a low-fat diet high in whole grains, fruits, vegetables and lean protein.

RELATED ARTICLE: Screening Guidelines for Gestational Diabetes

The American College of Obstetricians and Gynecologists recommends that all pregnant women be screened for gestational diabetes. Left untreated, gestational diabetes can lead to problems for the baby and mother. The greatest threat to the mother is an increased chance of needing a cesarean delivery. The baby may be affected by several complications. The most common fetal complication is "macrosomia," or a larger-than-normal baby. The baby grows large, because it gets so much glucose from the mother's blood. Consequently, the baby's pancreas pumps up production of insulin to get glucose into cells. Since the cells don't need all that glucose for energy, the baby stores it as fat. A large baby can have delivery complications, including birth injuries. Excess insulin or glucose can affect the development of a baby's lungs, leading to respiratory distress after birth. The macrosomic baby also has a risk of developing low blood sugar and should be checked soon after birth. Additionally, macrosomic babies have a greater risk of becoming obese as children and developing diabetes and related metabolic problems.

References

31 Crowther CA, Hiller JE, Moss JR, et al. Effect of treatment of gestational diabetes mellitus on pregnancy outcomes. N Engl J Med. 2005 Jun 16;352(24):2477-86.

32 American Diabetes Association. Gestational diabetes mellitus. Diabetes Care. 2004 Jan;27 Suppl 1:S88-90.

33 Langer D, Conway DL, Berkus MD, Xenakis EM, Gonzales O. A comparison of glyburide and insulin in women with gestational diabetes mellitus, N Engl J Med, 2000 Oct 19;343(16):1134-8.

34 Dabela D, et al. Increasing prevalence of GDM over time by birth cohort. Diabetes Care 2005;28:579-84.