title: Impact of micronutrient supplementation during pregnancy on birth weight, duration of gestation, and perinatal mortality in rural western China: double blind cluster randomised controlled trial.
abstract: OBJECTIVE
  To examine the impact of antenatal supplementation with multiple micronutrients or iron and folic acid compared with folic acid alone on birth weight, duration of gestation, and maternal haemoglobin concentration in the third trimester.
  
  
  METHODS
  Cluster randomised double blind controlled trial.
  
  
  METHODS
  Two rural counties in north west China.
  
  
  METHODS
  5828 pregnant women and 4697 live births.
  
  
  METHODS
  Villages were randomised for all pregnant women to take either daily folic acid (control), iron with folic acid, or multiple micronutrients with a recommended allowance of 15 vitamins and minerals.
  
  
  METHODS
  Birth weight, length, and head circumference measured within 72 hours after delivery. Neonatal survival assessed at the six week follow-up visit.
  
  
  RESULTS
  Birth weight was 42 g (95% confidence interval 7 to 78 g) higher in the multiple micronutrients group compared with the folic acid group. Duration of gestation was 0.23 weeks (0.10 to 0.36 weeks) longer in the iron-folic acid group and 0.19 weeks (0.06 to 0.32 weeks) longer in the multiple micronutrients group. Iron-folic acid was associated with a significantly reduced risk of early preterm delivery (<34 weeks) (relative risk 0.50, 0.27 to 0.94, P=0.031). There was a significant increase in haemoglobin concentration in both iron-folic acid (5.0 g/l, 2.0 to 8.0 g/l, P=0.001) and multiple micronutrients (6.9 g/l, 4.1 to 9.6 g/l, P<0.001) groups compared with folic acid alone. In post hoc analyses there were no significant differences for perinatal mortality, but iron-folic acid was associated with a significantly reduced early neonatal mortality by 54% (relative risk 0.46, 0.21 to 0.98).
  
  
  CONCLUSIONS
  In rural populations in China antenatal supplementation with iron-folic acid was associated with longer gestation and a reduction in early neonatal mortality compared with folic acid. Multiple micronutrients were associated with modestly increased birth weight compared with folic acid, but, despite this weight gain, there was no significant reduction in early neonatal mortality. Pregnant women in developing countries need sufficient doses of iron in nutrient supplements to maximise reductions in neonatal mortality. Trial registration ISRCTN08850194.
authors.affiliation: Department of Public Health, Xi'an Jiaotong University College of Medicine, PO Box 46, Xi'an, Shaanxi 710061, China.
authors.forename: Lingxia
authors.initials: L
authors.lastname: Zeng
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dibley
authors.forename: Yue
authors.initials: Y
authors.lastname: Cheng
authors.forename: Shaonong
authors.initials: S
authors.lastname: Dang
authors.forename: Suying
authors.initials: S
authors.lastname: Chang
authors.forename: Lingzhi
authors.initials: L
authors.lastname: Kong
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D002681:China; D016000:Cluster Analysis; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005865:Gestational Age; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D018977:Micronutrients / Q000008:administration & dosage*; D009748:Nutrition Disorders / Q000628:therapy*; D010349:Patient Compliance; D054238:Perinatal Mortality; D011247:Pregnancy; D011248:Pregnancy Complications / Q000628:therapy*; D011256:Pregnancy Outcome; D012423:Rural Health
chemical_list: D006454:Hemoglobins; D018977:Micronutrients