Risk of Congenital Anomalies Associated with Mother's Weight
The issue of maternal obesity is found to be associated with an increased risk in a range of structural congenital anomalies, shows the study recently published in the Journal of the American Medical Association (JAMA),
It has long been known that there are significant health issues of pre-pregnancy maternal obesity for both the mother and child. These include gestational diabetes, elevated blood pressure, and increased cesarean delivery rates.
Congenital anomalies are a leading cause of still-birth and infant mortality. One in five infants deaths in the United States can be attributed to congenital anomalies.
This study assessed current medical literature for associations between maternal overweight, maternal obesity, and congenital anomaly. The sources searched included MEDLINE, EMBASE, CINAHL, and Scopus. The article dates ranged from January 1966 to May 2008. Of the 1944 potential articles, only 39 included enough information regarding the maternal BMI (body mass index) and data on any congenital anomalies. Obese was defined as BMI greater than 31.
Their systematic review found that women who were obese at the start of pregnancy had a significant increased risk of a baby being affected by a neural tube defect (for example, spina bifida), cardiovascular anomaly (for example a septal anomaly), cleft palate and cleft lip and palate, anorectal atresia, hydrocephaly, or a limb reduction anomaly.
It is estimated that 3% of all live births in the United States are affected by such structural anomalies. It is estimated that 0.68 per 1000 births will be affected by a neural tube defect. It is estimated that 2.25 per 1000 births will be affected by a serious heart anomaly. This study estimates that when the mother is obese, the risk of a neural tube defect goes up to 0.47 per 1000 births and the risk of a serious heart anomaly goes up to 0.61 per 1000 births.
Considering the rise in obesity in the US and elsewhere, this could have serious health implications.
Maternal Overweight and Obesity and the Risk of Congenital Anomalies, a Systematic Review and Meta-analysis; JAMA, Feb 11, 2009, Vol 301, No 6, pp 636-650; Katherine J Stothard, PhD, Peter W G Tennant, MSc, Ruth Bell, MD, and Judith Rankin, PhD