Obese pregnant women are slightly more at risk of having babies with birth defects, according to an analysis of several studies published Tuesday in the Journal of the American Medical Association (JAMA).
While the absolute risk increase is likely to be small, congenital anomalies linked to maternal obesity include, "a neural tube defect (nearly twice the odds), including spina bifida (more than twice the odds)," the authors of the analysis said.
Other defects include "cleft palate and cleft lip and palate; anorectal atresia (abnormality of the anus/rectum); hydrocephaly (abnormal enlargement of the ventricles of the brain due to accumulation of cerebrospinal fluid); and a limb reduction anomaly," the authors said in the report dated February 11.
"The risk of gastroschisis (abdominal wall defect) among obese mothers was significantly reduced," they added.
Some three percent of US births are affected by "a structural anomaly with 0.68 per 1,000 births being affected by a neural tube defect and 2.25 per 1,000 births being affected by a serious heart anomaly," the report said.
"This has health implications, particularly given the continued rise in the prevalence of obesity in many countries," the authors said.
In the United States, one-third of women aged 15 and over are obese, with a body mass index (BMI) greater than 30 in 2004, the study said.
Congenital anomalies are a leading cause of stillbirth and infant death, accounting for one in five infant deaths in the United States, and are important contributors to preterm birth and childhood illnesses, according to background information in the article.