Maternal overweight and obesity and the risk of neural tube defects: a case-control study in China.

BACKGROUND

Studies have suggested that being obese before pregnancy is a risk factor for neural tube defects (NTDs), while results of many studies are controversial. This study aims to explore the association between maternal overweight and obesity before pregnancy and risk of NTDs.

METHODS

A 1:1 matched case-control study was conducted. Cases were 459 women who delivered infants or conceived fetuses with NTDs in two provinces of China and controls were 459 women with live-born infants, without an apparent congenital malformation, matched with cases by region, delivery hospital, and year of childbirth.

RESULTS

Compared with normal body weight, maternal obesity (body mass index, BMI ≥ 28 kg/m(2)) before pregnancy had a significant increased risk for NTDs as a group after adjusting for age, occupation, educational level, family income, parity, and use of folic acid (odds ratio, OR = 2.45; p < 0.05). No significant increase in NTD risk was found for maternal underweight (BMI < 18.5 kg/m(2)) and overweight (BMI from 24 to 28 kg/m(2)). For three subtypes of NTDs, anencephaly, spina bifida, and encephalocele, no significant increase in risk was found with maternal underweight, overweight, or obesity (all, p > 0.05).

CONCLUSIONS

Maternal obesity before pregnancy is associated with risk of NTDs and should be considered in maternal reproductive health care.