Obese women during pregnancy are at great risk of having babies with a wide range of birth defects, researchers from the University of Newcastle in England said in a report.

The report, a review of 39 studies, released in the Journal of the American Medical Association Wednesday, pointed out that babies of obese women had twice the risk of having a neural tube defect.

There is evidence that obesity before and during pregnancy may lead to an increased rate of birth defects, including spina bifida, heart problems, cleft palate and a number of other defects, lead researcher Katherine Stothard said.

"Our review confirms that maternal obesity raises the risk of a range of congenital anomalies," Stothard added in her report, adding "This has health implications, particularly given the continued rise in the prevalence of obesity in many countries."

The study also stressed that pregnant women carrying too much weight increase their risk of diabetes, high blood pressure as well as blood clots.

The study, looking at body mass index (BMI) and birth defects, further gave an evidence that about one-third of U.S. women of reproductive age are obese, and the birth defects account for one in five infant deaths in the country.

But, the British researchers said because birth abnormalities affect only about 2 to 4 percent of pregnancies, the absolute risk for obese women remains low.

Judith Rankin, another researcher who worked on the study, said, "Women who are thinking about trying for a baby need to check their own weight first and then think about seeking help if they are overweight."

BMI is a measurement that relates height and weight, with a score of 30 or above defining obesity. People with BMIs of 25 to 29.9 are said to be "overweight."

(Agencies via Xinhua News Agency February 11, 2009)