Dataset Information

Periconceptional folic acid supplementation and the risk of preterm births in China: a large prospective cohort study.

ABSTRACT:

Background

Folic acid-containing multivitamins have been associated with a reduced risk of preterm birth. We examined whether periconceptional use of folic acid alone reduced this risk.

Methods

Data were derived from a large population-based cohort study conducted in China to evaluate the prevention of neural tube defects with folic acid supplementation. The sample comprised 207 936 singleton live births delivered at gestational ages of 20-42 weeks to women from two provinces in southern China. Healthcare workers recorded folic acid intake prospectively each month. Gestational age calculation was based on the first day of the last menstrual period. Preterm births were categorized into three clinical subtypes: iatrogenic preterm birth, preterm premature rupture of membranes (PPROM) and spontaneous preterm birth. Logistic regression was used to evaluate the association between folic acid use and the risk of preterm birth, adjusting for potential confounders.

Results

The incidence of preterm birth was significantly lower among folic acid users (5.28%) than among non-users (6.10%). Folic acid use showed a 14% risk reduction for preterm birth overall [adjusted risk ratio (RR) = 0.86, 95% confidence interval (CI) 0.82-0.90]. This association was strongest for spontaneous preterm birth (adjusted RR = 0.81, 95% CI 0.78-0.86) and was not significant for iatrogenic preterm birth (adjusted RR = 0.97, 95% CI 0.88-1.07) or PPROM (adjusted RR = 1.07, 95% CI 0.93-1.23).

Conclusions

Daily intake of 400 ?g folic acid alone during the periconceptional period was associated with a reduced risk of spontaneous preterm birth.

SUBMITTER: Li Z

PROVIDER: S-EPMC4258769 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature

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Publications

Periconceptional folic acid supplementation and the risk of preterm births in China: a large prospective cohort study.

Li Zhiwen Z Ye Rongwei R Zhang Le L Li Hongtian H Liu Jianmeng J Ren Aiguo A

International journal of epidemiology 20140305 4

<h4>Background</h4>Folic acid-containing multivitamins have been associated with a reduced risk of preterm birth. We examined whether periconceptional use of folic acid alone reduced this risk.<h4>Methods</h4>Data were derived from a large population-based cohort study conducted in China to evaluate the prevention of neural tube defects with folic acid supplementation. The sample comprised 207 936 singleton live births delivered at gestational ages of 20-42 weeks to women from two provinces in s ...[more]

PMID: 24603317

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Project description:BACKGROUND: Health authorities in numerous countries recommend periconceptional folic acid to pregnant women to prevent neural tube defects. The objective of this study was to examine the association of folic acid supplementation during different periods of pregnancy and of dietary folate intake with the risk of spontaneous preterm delivery (PTD). METHODS: The Norwegian Mother and Child Cohort Study is a population-based prospective cohort study. A total of 65,668 women with singleton pregnancies resulting in live births in 1999-2009 were included. Folic acid supplementation was self-reported from 26 weeks before pregnancy until week 24 during pregnancy. At gestational week 22, the women completed a food frequency questionnaire, which allowed the calculation of their average total folate intake from foods and supplements for the first 4-5 months of pregnancy. Spontaneous PTD was defined as the spontaneous onset of delivery between weeks 22+0 and 36+6 (n?=?1,628). RESULTS: The median total folate intake was 266 ?g/d (interquartile range IQR 154-543) in the overall population and 540 ?g/d (IQR 369-651) in the supplement users. Eighty-three percent reported any folic acid supplementation from <8 weeks before to 24 weeks after conception while 42% initiated folic acid supplementation before their pregnancy. Cox regression analysis showed that the amount of folate intake from the diet (hazard ratio HR 1.16; confidence interval CI 0.65-2.08) and from the folic acid supplements (HR 1.04; CI 0.95-1.13) was not significantly associated with the risk of PTD. The initiation of folic acid supplementation more than 8 weeks before conception was associated with an increased risk for PTD (HR 1.19; CI 1.05-1.34) compared to no folic acid supplementation pre-conception. There was no significant association with PTD when supplementation was initiated within 8 weeks pre-conception (HR 1.01; CI 0.88-1.16). All analyses were adjusted for maternal characteristics and socioeconomic, health and dietary variables. CONCLUSIONS: Our findings do not support a protective effect of dietary folate intake or folic acid supplementation on spontaneous PTD. Pre-conceptional folic acid supplementation starting more than 8 weeks before conception was associated with an increased risk of PTD. These results require further investigation before discussing an expansion of folic acid supplementation guidelines.

Project description:OBJECTIVE:To find out the status of folic acid supplementation among women, to evaluate the prevention effects on neural tube defects (NTDs), and to explore the factors impact on folic acid supplementation compliance. METHODS:Based on the routine data of 92 121 women in prenatal health care and birth defect surveillance system in Tongzhou District of Beijing from 2013 to 2018, we described the prevalence of periconceptional folic acid supplementation, pre-pregnancy folic acid supplementation and regularly folic acid supplementation (compliance supplementation). Trend ?2 tests were used to evaluate the change of folic acid supplementation prevalence. The prevalence difference among the women with folic acid supplementation and without supplementation were tested with Fisher's exact test. Factors asso-ciated with folic acid supplementation compliance rate were analyzed with univariate and multivariate Logistic regression model. RESULTS:The prevalence of periconceptional folic acid supplementation during the six years was 90.08% and it was increased from 2013 to 2018, but the rate of pre-pregnancy and regular supplementation was only 41.5% and declined from 2013 to 2018, especially 2013 to 2015. The prevalence of NTDs among the fetuses whose mothers took folic acid during periconceptional period was 5.5/10 000, while the prevalence for the fetuses whose mothers did not take folic acid was 19.7/10 000 (P < 0.001), the rates ratio was 27.9% (?2=23.74, P < 0.001). The difference between the prevalence of NTDs among the fetuses whose mothers took folic acid only and multiple micronutrients was not statistically significant. After controlling the confounding factors, it was found that the compliant folic acid supplementation rates in women, whose household registrations were outside Beijing and whose education levels were junior high school or below, and who were younger than 25 years old, and who were multiparas and who were pre-pregnancy underweight or obese, were lower than those of the corresponding control groups (P < 0.05). CONCLUSION:The rate of folic acid supplementation among women in Tongzhou District of Beijing was relatively high, but their compliance was poor. Women who did not take folic acid during periconception seriously affected the prevention effect of NTDs. We should focus on women who are younger than 25 years old, lower educated, pre-pregnancy underweight or obese, multiparas and nonlocal household registers, in order to improve the periconceptional folic acid supplementation compliance and improve the effects of NTDs prevention.

Project description:BackgroundEvidence about the associations between maternal dietary patterns and preterm delivery is scarce in Eastern countries. The purpose of this study was to examine the associations between maternal dietary patterns during pregnancy and preterm delivery in a Chinese population.MethodsA total of 7352 mothers were included in the Born in Guangzhou Cohort Study, a prospective study in China. A validated self-administered food frequency questionnaire (FFQ) was used to assess maternal diet at 24-27 weeks of gestation. Dietary patterns were identified by cluster analysis. Gestational age was obtained from routine medical records. Preterm delivery was defined as delivery before 37 completed weeks of gestation, and was further classified into spontaneous and iatrogenic preterm delivery, and also early/moderate and late preterm delivery. Associations between dietary patterns and preterm delivery outcomes were assessed using logistic regression analyses.ResultsSix dietary patterns were identified, including 'Milk', 'Cereals, eggs, and Cantonese soups', 'Meats', 'Fruits, nuts, and Cantonese desserts', 'Vegetables', and 'Varied'. There were 351 (4.8%) preterm deliveries in this study population. Among those of preterm delivery, 16.2 and 83.8% were early/moderate and late preterm delivery, respectively. Compared with women of 'Vegetables' pattern, those of 'Milk' pattern had greater odds of overall preterm delivery (adjusted odds ratio [OR] 1.59, 95% confidence interval [CI] 1.11, 2.29, p?<?0.05), spontaneous preterm delivery (adjusted OR 1.73, 95% CI 1.14, 2.62, p?<?0.05) and late preterm delivery (adjusted OR 1.73, 95% CI 1.08, 2.62, p?<?0.05); those of 'Cereals, eggs, and Cantonese soups' and 'Fruits, nuts, and Cantonese desserts' patterns had greater odds of late preterm delivery (adjusted OR 1.54, 95% CI 1.01, 2.35 for 'Cereals, eggs, and Cantonese soups', adjusted OR 1.61, 95% CI 1.04, 2.50 for 'Fruits, nuts, and Cantonese desserts', respectively).ConclusionMaternal diet with frequent consumption of milk and less frequent consumption of vegetables during pregnancy might be associated with increased odds of preterm delivery. Future interventions should investigate whether increasing vegetable intake reduces preterm deliveries.

Dataset Information

Periconceptional folic acid supplementation and the risk of preterm births in China: a large prospective cohort study.

Background

Methods

Results

Conclusions

Publications

Periconceptional folic acid supplementation and the risk of preterm births in China: a large prospective cohort study.

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