Eating a good quality diet during the year before conception may protect against congenital heart malformations, research suggests.

American scientists enrolled 9,885 mothers of babies with major non-syndromic congenital heart defects and 9,468 mothers with unaffected babies. They divided the women into four (quartile) and 10 (decile) groups based on the quality of the mother’s diet in the year before pregnancy.

Women in the quartile and decile with the highest quality diet were 37 and 45 per cent respectively less likely to have a child with Tetralogy of Fallot – a complex malformation than can lead to dangerously low blood oxygen levels – than the group with the worse diet.

Women with the best diet were also 24 and 34 per cent respectively less likely to have a child with any conotruncal defect than those with the worse diet. Women in the quartile with the best diet were 23 and 14 per cent less likely to have a child with atrial septal defects and any septal defect respectively. Women in the decile with the best diet were 41 per cent less likely to have a child with atrial septal defects.

Being an observational study, the authors cannot draw conclusions about cause and effect, but do note that diet before pregnancy influences the risk of developing some other birth defects, including cleft palate and neural tube defects, for example.

^{(Arch Dis Child Fetal Neonatal Ed doi:10.1136/archdischild-2014-308013)}