Standards of therapy call for women who are taking oral hypoglycemic agents to change to insulin when they become pregnant. If a woman develops gestational diabetes that can’t be controlled with diet and exercise, she too is put on insulin. Researchers at the University of Texas have completed a study challenging this premise.
The goal of any diabetic therapy is to control hyperglycemia. In pregnant women, this is particularly important. Glucose passes through the placenta, but insulin doesn’t. High glucose levels in fetal circulation can overwhelm the fetus’s capacity to make insulin. The excess glucose results in macrosomia (large baby) as well as birth defects and sometimes stillbirth. Macrosomic babies have been found to have a higher rate of insulin resistance and to be at greater risk for future development of diabetes.
Based on a few studies done long ago, physicians were warned not to give oral hypoglycemic agents to pregnant women. The fear was that the drug would cross the placenta and stop the growing fetus from getting needed glucose. Present researchers say these studies were flawed and should not be the basis for a sweeping generalized ban on these drugs. Their study found less than five percent of the glyburide crossed the placenta.
The study involved 400 pregnant diabetics, 200 of which took glyburide and the other 200 insulin. Both groups had the same number of physician visits, average age, gestational age (more than 11 weeks but less than 33 weeks), and dose. Measurements included fasting blood sugar, hypoglycemic events, macrosomia, ICU visits, congenital malformations, and metabolic, hematologic and respiratory complications. There were no significant differences between the groups in any category. Fetal mortality rates for both groups were the same as the general population.
Oral hypoglycemic agents are more cost effective than insulin, and most women will tell you they’d rather take a pill than inject themselves. Regardless of medication, blood glucose monitoring must be done on schedule.
While these results are promising, under no circumstances should a pregnant woman make any changes in her present diabetic regimen without first discussing it with her health-care professional.