Maternal Obesity Linked to Structural Birth Defects
Higher incidence of seven defects seen in children whose mothers were obese before pregnancy
WEDNESDAY, Aug. 8 (HealthDay News) -- Women who are obese before pregnancy may be more likely to give birth to children with structural defects such as spina bifida and heart defects, according to a report published in the August issue of the Archives of Pediatrics & Adolescent Medicine.
D. Kim Waller, Ph.D., of the University of Texas in Houston, and colleagues compared the pre-pregnancy body mass indexes of 10,249 women in eight states whose babies were born with birth defects with those of 4,065 controls whose babies were born without birth defects. Women with type 2 diabetes were excluded from the study.
The researchers found a weak-to-moderate positive association between maternal obesity in seven of 16 categories of birth effects, with odds ratios of 1.33-2.10 for spina bifida, heart defects, anorectal atresia, hypospadias, limb reduction defects, diaphragmatic hernia, and omphalocele. They also found a strong inverse association between maternal obesity and gastroschisis (odds ratio 0.20). The results were similar after the researchers excluded women who developed gestational diabetes.
"The mechanisms underlying these associations are not yet understood but may be related to undiagnosed diabetes," the authors write. "Both animal studies and human studies provide substantial evidence that alterations in glycemic control are responsible for an increased risk of a range of structural birth defects among women who have diabetes prior to becoming pregnant. Thus, a similar mechanism to that occurring in women with diabetes may be responsible for the associations observed between maternal obesity and specific categories of birth defects."