British Journal of Nutrition

Full Papers

Dietary Surveys and Nutritional Epidemiology

Periconception folic acid supplementation, fetal growth and the risks of low birth weight and preterm birth: the Generation R Study

Sarah Timmermansa1a2 c1, Vincent W. V. Jaddoea1a3a4, Albert Hofmana3, Régine P. M. Steegers-Theunissena2a3a4a5 and Eric A. P. Steegersa2

a1 The Generation R Study Group, Erasmus MC, PO Box 2040, 3000CA Rotterdam, The Netherlands

a2 Division of Obstetrics & Prenatal Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, PO Box 2040, 3000CA Rotterdam, The Netherlands

a3 Department of Epidemiology, Erasmus MC, PO Box 2040, 3000CA Rotterdam, The Netherlands

a4 Department of Paediatrics, Erasmus MC, PO Box 2040, 3000CA Rotterdam, The Netherlands

a5 Department of Clinical Genetics, Erasmus MC, PO Box 2040, 3000CA Rotterdam, The Netherlands

Abstract

Countries worldwide, including the Netherlands, recommend that women planning pregnancy use a folic acid supplement during the periconception period. Some countries even fortify staple foods with folic acid. These recommendations mainly focus on the prevention of neural tube defects, despite increasing evidence that folic acid may also influence birth weight. We examined whether periconception folic acid supplementation affects fetal growth and the risks of low birth weight, small for gestational age (SGA) and preterm birth, in the Generation R Study in Rotterdam, the Netherlands. Main outcome measures were fetal growth measured in mid- and late pregnancy by ultrasound, birth weight, SGA and preterm birth in relation to periconception folic supplementation (0·4–0·5 mg). Data on 6353 pregnancies were available. Periconception folic acid supplementation was positively associated with fetal growth. Preconception folic acid supplementation was associated with 68 g higher birth weight (95 % CI 37·2, 99·0) and 13 g higher placental weight (95 % CI 1·1, 25·5), compared to no folic acid supplementation. In these analyses parity significantly modified the effect estimates. Start of folic acid supplementation after pregnancy confirmation was associated with a reduced risk of low birth weight (OR 0·61, 95 % CI 0·40, 0·94). Similarly, reduced risks for low birth weight and SGA were observed for women who started supplementation preconceptionally, compared to those who did not use folic acid (OR 0·43, 95 % CI 0·28, 0·69 and OR 0·40, 95 % CI 0·22, 0·72). In conclusion, periconception folic acid supplementation is associated with increased fetal growth resulting in higher placental and birth weight, and decreased risks of low birth weight and SGA.

(Received June 04 2008)

(Revised January 05 2009)

(Accepted January 27 2009)

(Online publication March 30 2009)

Correspondence:

c1 Corresponding author: Dr Sarah Timmermans, fax +31 10 7036815, email s.timmermans@erasmusmc.nl

Footnotes

Abbreviations: SGA, small for gestational age

0Comments