Folic Acid Supplementation and Spontaneous Preterm Birth: Adding Grist to the Mill?

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.

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Folic acid supplementation and risk reduction in preterm birth

American Journal of Clinical Nutrition ◽

10.3945/ajcn.111.026690 ◽

2011 ◽

Vol 94 (6) ◽

pp. 1651-1652 ◽

Cited By ~ 2

Author(s):

Andrew E Czeizel ◽

Ferenc Bánhidy

Keyword(s):

Folic Acid ◽

Preterm Birth ◽

Risk Reduction ◽

Folic Acid Supplementation ◽

Acid Supplementation

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Pre-conceptional intake of folic acid supplements is inversely associated with risk of preterm birth and small-for-gestational-age birth: a prospective cohort study

British Journal Of Nutrition ◽

10.1017/s0007114515004663 ◽

2015 ◽

Vol 115 (3) ◽

pp. 509-516 ◽

Cited By ~ 17

Author(s):

Ju-Sheng Zheng ◽

Yuhong Guan ◽

Yimin Zhao ◽

Wei Zhao ◽

Xuejuan Tang ◽

...

Keyword(s):

Cohort Study ◽

Folic Acid ◽

Preterm Birth ◽

Birth Cohort ◽

Gestational Age ◽

Small For Gestational Age ◽

Pregnancy Outcomes ◽

Lower Risk ◽

Folic Acid Supplementation ◽

Acid Supplementation

AbstractAssociations of folic acid supplementation with risk of preterm birth (PTB) and small-for-gestational-age (SGA) birth were unclear for the Chinese populations. The aim of the present study was to investigate the associations in a large Chinese prospective cohort study: the Jiaxing Birth Cohort. In the Jiaxing Birth Cohort, 240 954 pregnant women visited local clinics or hospitals within their first trimester in Southeast China during 1999–2012. Information on anthropometric parameters, folic acid supplementation and other maternal characteristics were collected by in-person interviews during their first visit. Pregnancy outcomes were recorded during the follow-up of these participants. Multinomial logistic regression was used to examine the association of folic acid supplementation with pregnancy outcomes. The prevalence of folic acid supplementation was 24·9 % in the cohort. The prevalence of PTB and SGA birth was 3·48 and 9·2 %, respectively. Pre-conceptional folic acid supplementation was associated with 8 % lower risk of PTB (relative risk (RR) 0·92; 95 % CI 0·85, 1·00; P=0·04) and 19 % lower risk of SGA birth (RR 0·81; 95 % CI 0·70, 0·95; P=0·008), compared with non-users. Higher frequency of pre-conceptional folic acid use was associated with lower risk of PTB (Ptrend=0·032) and SGA birth (Ptrend=0·046). No significant association between post-conceptional initiation of folic acid supplementation and either outcome was observed. In conclusion, the present study suggests an association between pre-conceptional, but not post-conceptional, folic acid supplementation and lower risk of PTB and SGA birth in the Jiaxing Birth Cohort. Further research in other cohorts of large sample size is needed to replicate these findings.

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Birth Outcomes of Newborns after Folic Acid Supplementation in Pregnant Women with Early and Late Pre-Eclampsia: A Population-Based Study

Advances in Preventive Medicine ◽

10.4061/2011/127369 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Ferenc Bánhidy ◽

Abdallah Dakhlaoui ◽

István Dudás ◽

Andrew E. Czeizel

Keyword(s):

Folic Acid ◽

Preterm Birth ◽

Pregnant Women ◽

Birth Outcomes ◽

Early Pregnancy ◽

Early Onset ◽

Low Birthweight ◽

Late Onset ◽

Folic Acid Supplementation ◽

Acid Supplementation

Objective. To evaluate the rate of preterm birth and low birth weight in the newborns of pregnant women with early and late onset pre-eclampsia according to folic acid supplementation.Study design. Birth outcomes of newborns were evaluated in 1,017 (2.7%) pregnant women with medically recorded pre-eclampsia and 37,134 pregnant women without pre-eclampsia as reference in the Hungarian Case-Control Surveillance System of Congenital Abnormalities, 1980–1996, in addition these study groups were differentiated according to the supplementation of high dose of folic acid alone from early pregnancy.Results. Pregnant women with pre-eclampsia associated with a higher rate of preterm birth (10.2% versus 9.1%) and low birthweight (7.9% versus 5.6%). There was a lower risk of preterm birth (6.8%) of newborn infants born to pregnant women with early onset pre-eclampsia after folic acid supplementation from early pregnancy though the rate of low birthweight was not reduced significantly. There was no significant reduction in the rate of preterm birth and low birthweight in pregnant women with late onset pre-eclampsia after folic acid supplementation.Conclusion. The rate of preterm birth in pregnant women with early onset pre-eclampsia was reduced moderately by high doses of folic acid supplementation from early pregnancy.

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