Maternal folic acid supplementation trends 2009-2013.

Objective: We analyzed trends in folic acid supplementation among women booking for antenatal care between 2009 and 2013.

Design: Prospective observational study.

Setting: Large university teaching hospital.

Population: We included all women who delivered an infant ≥500 g from 1 January 2009 to 31 December 2013.

Methods: Body mass index was calculated using early pregnancy weight and height measured at first antenatal visits. Sociodemographic and clinical data were gathered prospectively. Multivariate logistic regression analyses were applied to determine the correlates of periconceptional folic acid supplementation.

Main Outcome Measures: Rates and correlates of folic acid supplementation.

Results: Of 42 362 women, 99.2% (n = 42 042) were suitable for analysis. The mean age was 30.7 years and mean body mass index was 25.6 kg/m(2) , 40.7% (n = 17 054) were primigravidas and 70.6% (n = 29 741) were Irish-born. Overall, 43.9% (n = 18 473) took periconceptional (preconceptional and postconceptional) folic acid, 49.4% (n = 20 782) took postconceptional folic acid only, and 6.6% (n = 2787) took no folic acid. The women most likely to take folic acid were those who planned their pregnancy and were >30 years old, non-obese, Irish-born and employed professionally. The periconceptional folic acid rate decreased from 45.1% in 2009 to 43.1% in 2013 (p = 0.01). Over five years, periconceptional folic acid supplementation decreased among women who were multiparous (43.8-41.6%, p = 0.02), aged 30-39 years (58.9-55.0%, p < 0.001), Irish-born (50.1-47.1%, p < 0.001) and obese (38.6-36.9%, p = 0.02).

Conclusion: Overall, the rate of periconceptional folic acid supplementation decreased in the five years 2009-2013, particularly among women who were multiparous, aged 30-39 years, Irish-born and obese.