title: Maternal folate status, but not that of vitamins B-12 or B-6, is associated with gestational age and preterm birth risk in a multiethnic Asian population.
abstract: BACKGROUND
  Maternal folate, vitamin B-12, and vitamin B-6 concentrations during pregnancy have been shown to influence birth outcomes, but the evidence is inconclusive.
  
  
  OBJECTIVE
  We aimed to examine the associations of maternal B-vitamin status with gestational age, birth weight, and length in a birth cohort study in Singapore.
  
  
  METHODS
  Maternal blood samples (n = 999) collected during weeks 26-28 of gestation were assayed for plasma folate, vitamin B-12, and vitamin B-6 concentrations. Birth weight and gestational age data were obtained from hospital records, and other anthropometric variables were measured within 72 h after birth. Relations between B-vitamin status and birth outcomes were assessed by linear or logistic regression with adjustment for potential confounders.
  
  
  RESULTS
  Median (IQR) plasma concentrations were 34.4 (24.5-44.6) nmol/L for folate, 209 (167-258) pmol/L for vitamin B-12, and 61.8 (25.9-113) nmol/L for vitamin B-6. We found that higher plasma folate concentrations were associated with a longer gestational age (0.12 wk per SD increase in folate; 95% CI: 0.02, 0.21) and tended to be associated with lower risk of all preterm birth (delivery at <37 wk of gestation; OR: 0.79; 95% CI: 0.63, 1.00) and spontaneous preterm birth (OR: 0.76; 95% CI: 0.56, 1.04). Overall, concentrations of maternal folate, vitamin B-12, and vitamin B-6 were not independently associated with birth weight or being born small for gestational age (SGA; birth weight <10th percentile for gestational age).
  
  
  CONCLUSIONS
  Higher maternal folate concentrations during late pregnancy were associated with longer gestational age and tended to be associated with a lower risk of preterm birth in this multiethnic Asian population. In contrast, the results of our study suggested little or no benefit of higher folate concentrations for reducing the risk of SGA or of higher vitamin B-6 and vitamin B-12 concentrations for reducing the risk of preterm birth or SGA.
authors.affiliation: Saw Swee Hock School of Public Health.
authors.forename: Ling-Wei
authors.initials: LW
authors.lastname: Chen
authors.affiliation: Singapore Institute for Clinical Sciences, A*STAR, Singapore.
authors.forename: Ai Lin
authors.initials: AL
authors.lastname: Lim
authors.affiliation: Singapore Institute for Clinical Sciences, A*STAR, Singapore.
authors.forename: Marjorelee
authors.initials: M
authors.lastname: Colega
authors.affiliation: Departments of Obstetrics and Gynecology.
authors.forename: Mya-Thway
authors.initials: MT
authors.lastname: Tint
authors.affiliation: Pediatrics, and.
authors.forename: Izzuddin M
authors.initials: IM
authors.lastname: Aris
authors.affiliation: Saw Swee Hock School of Public Health.
authors.forename: Chuen Seng
authors.initials: CS
authors.lastname: Tan
authors.affiliation: Singapore Institute for Clinical Sciences, A*STAR, Singapore Departments of Obstetrics and Gynecology.
authors.forename: Yap-Seng
authors.initials: YS
authors.lastname: Chong
authors.affiliation: Singapore Institute for Clinical Sciences, A*STAR, Singapore Liggins Institute, University of Auckland, Auckland, New Zealand.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Gluckman
authors.affiliation: Medical Research Council Lifecourse Epidemiology Unit and National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton National Health Service (NHS) Foundation Trust, Southampton, United Kingdom.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Godfrey
authors.affiliation: Departments of Maternal Fetal Medicine and.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Kwek
authors.affiliation: Saw Swee Hock School of Public Health.
authors.forename: Seang-Mei
authors.initials: SM
authors.lastname: Saw
authors.affiliation: Pediatric Endocrinology, KK Women's and Children's Hospital, Singapore; and Duke-NUS Graduate Medical School, Lee Kong Chian School of Medicine, Singapore.
authors.forename: Fabian
authors.initials: F
authors.lastname: Yap
authors.affiliation: Singapore Institute for Clinical Sciences, A*STAR, Singapore Pediatrics, and.
authors.forename: Yung Seng
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Singapore Institute for Clinical Sciences, A*STAR, Singapore Pediatrics, and Clinical Nutrition Research Centre rob_martinus_van_dam@nuhs.edu.sg mary_chong@sics.a-star.edu.sg.
authors.forename: Mary Foong-Fong
authors.initials: MF
authors.lastname: Chong
authors.affiliation: Saw Swee Hock School of Public Health Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore rob_martinus_van_dam@nuhs.edu.sg mary_chong@sics.a-star.edu.sg.
authors.forename: Rob M
authors.initials: RM
authors.lastname: van Dam
mesh_terms: D000328:Adult; D044466:Asian People; D001724:Birth Weight; D001827:Body Height; D015331:Cohort Studies; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005865:Gestational Age; D006801:Humans; D009752:Nutritional Status / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000097:blood*; D011446:Prospective Studies; D012307:Risk Factors; D012846:Singapore; D014805:Vitamin B 12 / Q000097:blood; D025101:Vitamin B 6 / Q000097:blood
chemical_list: D025101:Vitamin B 6; D005492:Folic Acid; D014805:Vitamin B 12
keywords: birth length; birth outcomes; birth weight; folate; gestational age; pregnancy; preterm birth; small for gestational age; vitamin B-12; vitamin B-6