Infants born to women with type 1 diabetes tend to be abnormally large, which is potentially dangerous for both mother and baby. The birthweights of such infants have not changed over time, but many more of them are surviving, researchers in Scotland report.

“While there have been important and gratifying improvements in perinatal mortality in diabetes complicated by type 1 diabetes over the last 40 years much remains to be done,” Dr. Robert S. Lindsay from University of Glasgow told Reuters Health.

He explained that there’s a connection between a mother’s blood glucose levels and the birthweight of her baby, but exactly what leads to macrosomia, as abnormally large size is termed, in individual pregnancies is not well understood.

Lindsay and his colleagues examined changes in perinatal mortality and the birthweight of babies born between 1960 and 1999at one hospital to mothers with long-standing type 1 diabetes.

Perinatal mortality rates improved from 225 deaths per 1000 births in the 1960s, declining each decade down 10 deaths per 1000 births in the 1990s, the team reports in the medical journal Obstetrics & Gynecology

During that same period, however, average birthweight of the infants remained considerably higher than the norm for the general population.

Changes in diabetes care and obstetrics “have resulted in enormous improvements in the outlook for offspring of mothers with diabetes,” the investigators write. “Somewhat surprisingly, this has not been associated with a reduction in overgrowth of the fetus.”

“Our current studies are concentrating on the long-term effect of maternal diabetes on offspring health,” Lindsay added.

SOURCE: Obstetrics & Gynecology, June 2006.