Diabetes may be associated with fetal abnormalities in obese women

The association between obesity and fetal anomalies may be related to underlying diabetes and uncontrolled hyperglycemia, rather than maternal weight alone, according to new study findings.

Researchers from the University of Alabama at Birmingham Center for Women’s Reproductive Health conducted a cross-sectional study using pooled data from a perinatal database. They identified 41,902 women who delivered a single pregnancy from 1991 to 2004. The researchers defined and compared patient cohorts during three five-year periods: 1991 to 1994; 1995 to 1999; and 2000 to 2004. The analysis was limited to black and white women only.

Mean maternal weight, BMI, major anomalies and the number of women who weighed more than 200 lb, had a BMI >29 and had pregestational diabetes increased for each time period (P<.001 for all).

According to the researchers, maternal obesity was not significantly or independently associated with presence of a major fetal anomaly.

Multivariable logistic regression indicated that the prevalence of pregestational diabetes was the major factor contributing to the increased rate of hereditary anomalies (OR=3.8; 95% CI, 2.1-6.6).

“Interestingly, we saw a 250% increase in the prevalence of pregestational diabetes during [1991 to 2001], and its presence, either with or without associated obesity, seems to be a major contributor to the increasing rate of anomalies in our population,” the researchers wrote.

The overall population-attributable risk of anomalies associated with obesity increased from 0% during 1991 to 1994 to 6.1% in 2000 to 2004. The population-attributable risk of anomalies associated with diabetes increased from 3.3% to 9.2% during the same time periods. Further, the proportion of anomalies associated with diabetes increased significantly in obese women with diabetes, from 48% in 1991 to 1994 to 74% in 2000 to 2004.

“Because hyperglycemia is a major contributor to developmental malformations, interventions to address obesity and identify women at risk for diabetes and hyperglycemia should be considered in efforts to reduce the occurrence of congenital anomalies,” the researchers concluded.

Biggio JR. Obstet Gynecol. 2010;115:290–296.