Researchers are reporting that treatment of even the mildest forms of gestational diabetes halves the risk of delivering newborns with excess body fat and shoulder dystocia at birth. Treatment also results in fewer cesarean deliveries and a reduction in risk for pre-eclampsia and hypertensive disorders.
According to principal investigator, Mark B. Landon, MD, obstetrician from Ohio State University Medical Center at Columbus, “Currently, physicians wonder whether treatment actually benefits patients with gestational diabetes or poses risks.” There is concern that current diagnostic criteria for gestational diabetes are not predicated on any pregnancy outcomes.
“The findings from our study lend support to the fact that whilst obstetricians maintain skepticism about treating the mildest forms, it is now evident that women should be aggressively treated because there is significant clinical benefit attached to this.”
In this randomized controlled study, 958 women who were between 24 and 31 weeks of gestation and who had been given a diagnosis of mild gestational diabetes mellitus received either usual prenatal care (control group) or a combined treatment regimen, consisting of dietary intervention, self-monitoring of blood glucose, and insulin therapy, if necessary.
Patients receiving treatment adhered to a diet guided by close blood glucose monitoring using a portable meter. Monitoring required the patient to perform at least 4 tests per day during fasting and after meals to ensure that the diet plan was maintaining her blood glucose at the desired level.
Compared with the control group, the 485 women in the treatment group showed significant reductions in secondary study outcomes, including mean birth weight (3302 vs. 3408 g), neonatal mass (427 vs. 464 g), frequency of infants who were large for their gestational age (7.1% vs. 14.5%), birth weight greater than 4000 g (5.9% vs. 14.3%), shoulder dystocia (1.5% vs. 4.0%), and cesarean delivery (26.9% vs. 33.8%). Treatment was also associated with reduced rates of pre-eclampsia and gestational hypertension (combined rates for the 2 conditions, 8.6% vs. 13.6%; P = .01).
Moshe Hod, MD, director of the Division of Maternal Fetal Medicine at Tel-Aviv University in Israel, commenting on the study, said that this is one of the most important studies to date. Dr. Hod sits on the steering committee of the Hyperglycemia and Adverse Outcomes Study (HAPO), an ongoing analysis of gestational diabetes that aims to develop an international consensus for the diagnosis and treatment of carbohydrate intolerance during pregnancy.
This study showed a strong continuous association between maternal glucose concentration and increasing birth weight, in addition to cord-blood serum C-peptide levels and other perinatal complications. These findings were evident at concentrations usually used for the diagnosis of diabetes mellitus.
“Both this study and the HAPO study will change the management of gestational diabetes, providing for the first time the scientific evidence needed to come up with recommendations for universal diagnostic criteria and treatment protocols. Both studies are complementary; one study provides evidence of strong and continuous associations of maternal glucose levels with perinatal outcomes, and the other provides evidence that treatment of these conditions improves adverse perinatal outcome,” Dr. Hod said.
Patrick Catalano, MD, from the Department of Maternal and Fetal Medicine at Case Western Reserve University in Cleveland, Ohio, adds that this study shows clear benefits for both mother and fetus. “For the fetus, we are interested in the long-term growth and long-term risk of the child developing diabetes or metabolic syndrome and obesity. By starting out better, we think this may be important for long-term outcomes. Also, if mothers apply these rules after pregnancy, then it might prevent them and possibly their children from developing adult-onset Type 2 diabetes later. It has an effect down the line.”
“The frequency of gestational diabetes is increasing worldwide, so it is important to have level 1 evidence that treatment does make a difference. This is particularly important in areas of the world where the healthcare dollar is stretched and has come under increasing scrutiny,” concluded Dr. Landon.
European Association for the Study of Diabetes (EASD) 45th Annual Meeting: Symposium S09. Presented October 1, 2009. N Engl J Med. 2009;361:1339-1348.