OBJECTIVE: To develop a model of the impact of population-wide periconceptional @entity1501 supplementation on @entity601 and twin births. DESIGN: A hypothetical cohort of 100,000 pregnancies > or =20 weeks, plus terminations of pregnancy after prenatal diagnosis before 20 weeks. METHODS: Application of pooled data on the relative risks for @entity601 and twins following periconceptional @entity1501 from meta-analysis of the randomised trials. MAIN OUTCOME MEASURES: 1. Pregnancies with a neural tube defect (i.e. terminations of pregnancy, perinatal @entity204 , and surviving @entity1 ); 2. twin births (i.e. preterm births, perinatal @entity204 , postneonatal @entity204 , @entity600 , @entity306 ); 3. numbers needed to treat. RESULTS: The change in @entity601 would be 75 fewer terminations (95% CI -47, -90), 30 fewer perinatal @entity204 (95% CI 18, -35), and 13 fewer surviving @entity1 with a neural tube defect (95% CI -8, -16). The change in twinning would be an additional 572 twin confinements (95% CI -100, +1587), among whom there would be 63 very preterm twin confinements (95% CI -11, +174), 54 perinatal and postneonatal @entity204 (95% CI -9, +149), 48 surviving twins with a @entity600 (95% CI -8, +133), and nine with @entity306 (95% CI -2, +26). The numbers needed to treat for the prevention of one pregnancy with a neural tube defect is 847, for the birth of one additional set of twins is 175, for the birth of one additional set of very preterm twins is 1587, and for the birth of an additional twin with any of the following outcomes (perinatal death, postneonatal death, survival with a @entity600 , or survival with @entity306 ) is 901. CONCLUSIONS: Monitoring rates of @entity601 and twinning is essential as supplementation or fortification with @entity1501 is implemented.

Modelling the potential impact of population-wide periconceptional XXXX /multivitamin supplementation on multiple births.

@entity1501 :: ('MESH:D005492', 'Chemical') :: ['folate'] @entity1 :: ('9606', 'Species') :: ['infants'] @entity600 :: ('MESH:D000014', 'Disease') :: ['birth defect', 'birth defects'] @entity601 :: ('MESH:D009436', 'Disease') :: ['neural tube defects'] @entity204 :: ('MESH:D003643', 'Disease') :: ['deaths'] @entity306 :: ('MESH:D002547', 'Disease') :: ['cerebral palsy']
@entity1501 :: (MESH:D005492,Chemical) :: ['folate']
