Objective: The purpose of this nested cohort study was to compare the rate of pre-pregnancy supplementation in obese women with that of women with a normal BMI.
Methods: Pregnant women were enrolled at their convenience in a large university hospital. Weight and height were measured in the first trimester and BMI categorised.
Results: Of the 288 women, 35.1% were in the normal, 29.5% in the overweight and 35.4% in the obese BMI categories. Only 45.1% (n = 46) of the obese women took pre-pregnancy folic acid compared with 60.4% (n = 61) of women with a normal BMI (p < 0.03). The lower incidence of folic acid supplementation in obese women was associated with an unplanned pregnancy in 36.3% of women compared with 22.8% in the normal BMI category (p < 0.04).
Conclusions: Obese women should take folate supplements whether they are planning to conceive or not.