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

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

The study examines 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.

The cluster randomised double blind controlled trial took place in two rural counties in north west China with 5,828 pregnant women and 4,697 live births. 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.

Key findings include:

  • Birth weight was 42 g higher in the multiple micronutrients group compared with the folic acid group.
  • Duration of gestation was 0.23 weeks longer in the iron-folic acid group and 0.19 weeks longer in the multiple micronutrients group.
  • Iron-folic acid was associated with a significantly reduced risk of early preterm delivery (<34 weeks).
  • There was a significant increase in haemoglobin concentration in both iron-folic acid and multiple micronutrients 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%.
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.
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