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Liu X, Lv L, Zhang H, Zhao N, Qiu J, He X, Zhou M, Xu X, Cui H, Liu S, Lerro C, Lin X, Zhang C, Zhang H, Xu R, Zhu D, Dang Y, Han X, Bai H, Chen Y, Tang Z, Lin R, Yao T, Su J, Wang W, Wang Y, Ma B, Huang H, Liang J, Qiu W, Liu Q, Zhang Y. Folic acid supplementation, dietary folate intake and risk of preterm birth in China. Eur J Nutr 2015; 55:1411-22. [PMID: 26138063 DOI: 10.1007/s00394-015-0959-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 06/09/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE Folic acid supplementation has been suggested to reduce the risk of preterm birth. However, results from previous epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake during pre- and post-conception reduces the risk of preterm birth. METHODS We analyzed data from a birth cohort study conducted between 2010 and 2012 in Lanzhou, China, including 10,179 pregnant women with live singleton births. RESULTS Compared to non-users, folic acid supplement users with >12-week duration had a reduced risk of preterm birth (OR 0.67, 95 % CI 0.55-0.83) with a significant dose-response relationship (P for trend = 0.01). A similar pattern was observed for spontaneous preterm birth. Stronger associations were seen for ever use of folic acid supplement and very preterm birth (OR 0.50, 95 % CI 0.36-0.69) and spontaneous very preterm birth (OR 0.42, 95 % CI 0.29-0.63). Dietary folate intake during preconception and pregnancy were also associated with reduced risk of preterm birth (OR 0.68, 95 % CI 0.56-0.83, OR 0.57, 95 % CI 0.47-0.70 for the highest quartiles, respectively), particularly for spontaneous very preterm (OR 0.41, 95 % CI 0.24-0.72, OR 0.26, 95 % CI 0.15-0.47 for the highest quartiles, respectively). There were also decreased risks of preterm birth observed per 10-µg increase in dietary folate intake, and similar associations were found after stratification by folic acid supplementation status. CONCLUSIONS Our results suggest that folic acid supplementation and higher dietary folate intake during preconception and pregnancy reduces the risk of preterm birth, and the protective effect varies by preterm subtypes.
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Affiliation(s)
- Xiaohui Liu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Ling Lv
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Hanru Zhang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Nan Zhao
- Yale School of Public Health, 60 College Street, New Haven, CT, 06520, USA
| | - Jie Qiu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Xiaochun He
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Min Zhou
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Xiaoying Xu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Hongmei Cui
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Sufen Liu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Catherine Lerro
- Yale School of Public Health, 60 College Street, New Haven, CT, 06520, USA
| | - Xiaojuan Lin
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Chong Zhang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Honghong Zhang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Ruifeng Xu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Daling Zhu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Yun Dang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Xudong Han
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Haiya Bai
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Ya Chen
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Zhongfeng Tang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Ru Lin
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Tingting Yao
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Jie Su
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Wendi Wang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Yueyuan Wang
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Bin Ma
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Huang Huang
- Yale School of Public Health, 60 College Street, New Haven, CT, 06520, USA
| | - Jiaxin Liang
- Yale School of Public Health, 60 College Street, New Haven, CT, 06520, USA
| | - Weitao Qiu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China
| | - Qing Liu
- Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, 730050, Gansu Province, China.
| | - Yawei Zhang
- Yale School of Public Health, 60 College Street, New Haven, CT, 06520, USA.
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Sengpiel V, Bacelis J, Myhre R, Myking S, Devold Pay AS, Haugen M, Brantsæter AL, Meltzer HM, Nilsen RM, Magnus P, Vollset SE, Nilsson S, Jacobsson B. Folic acid supplementation, dietary folate intake during pregnancy and risk for spontaneous preterm delivery: a prospective observational cohort study. BMC Pregnancy Childbirth 2014; 14:375. [PMID: 25361626 PMCID: PMC4240839 DOI: 10.1186/s12884-014-0375-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/16/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Health authorities in numerous countries recommend periconceptional folic acid supplementation to prevent neural tube defects. The objective of this study was to examine the association of dietary folate intake and folic acid supplementation during different periods of pregnancy 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 66,014 women with singleton pregnancies resulting in live births in 2002-2009 were included. Folic acid supplementation was self-reported from 26 weeks before pregnancy until pregnancy week 24. 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 = 1,755). RESULTS The median total folate intake was 313 μg/d (interquartile range IQR 167-558) in the overall population and 530 μg/d (IQR 355-636) in the supplement users. Eighty-five percent reported any folic acid supplementation from <8 weeks before to 24 weeks after conception while only 44% initiated folic acid supplementation before pregnancy. Cox regression analysis showed that the amount of dietary folate intake (hazard ratio HR 1.00; confidence interval 95% CI 0.61-1.65) and supplemental folate intake (HR 1.00; CI 1.00-1.00) 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 spontaneous PTD (HR 1.18; CI 1.05-1.32) compared to no folic acid supplementation preconception. There was no significant association with PTD when supplementation was initiated within 8 weeks preconception (HR 0.99; CI 0.87-1.13). 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. Preconceptional folic acid supplementation starting more than 8 weeks before conception was associated with an increased risk of spontaneous PTD. These results require further investigation before discussing an expansion of folic acid supplementation guidelines.
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Sengpiel V, Bacelis J, Myhre R, Myking S, Pay AD, Haugen M, Brantsæter AL, Meltzer HM, Nilsen RM, Magnus P, Vollset SE, Nilsson S, Jacobsson B. Folic acid supplementation, dietary folate intake during pregnancy and risk for spontaneous preterm delivery: a prospective observational cohort study. BMC Pregnancy Childbirth 2013; 13:160. [PMID: 23937678 PMCID: PMC3751653 DOI: 10.1186/1471-2393-13-160] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 08/05/2013] [Indexed: 11/16/2022] Open
Abstract
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 μg/d (interquartile range IQR 154–543) in the overall population and 540 μg/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.
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Affiliation(s)
- Verena Sengpiel
- Department of Obstetrics and Gynaecology, Sahlgrenska Academy, Sahlgrenska University Hospital/Östra, SE-416 85 Göteborg, Sweden.
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