TABLE 3

Review of Key Impacts of Nutrition Interventions Delivered During Preconception and Pregnancy

Key InterventionsSummary Effects With Implications for Developmental Outcomes (Direct Developmental Effects)
Folic acid fortification and supplementation for women of childbearing age, 3 SRs, HIC and LMICPrevention of neural tube defects: reduced risk of neural tube defects with supplementation (RR 0.31, 95% CI 0.17 to 0.58; N = 6708 in 5 studies) and fortification (RR 0.59, 95% CI 0.52 to 0.68; 11 studies)
Iodine supplementation, 1 SR, HIC and LMICProtection from severe developmental deficits: reduced risk of cretinism (RR 0.27, 95% CI 0.12 to 0.60; N = 9500 in 5 studies)
Improved cognitive development: 10% to 20% increase in cognitive development scores (N = 1200 in 4 studies)
Iron and iron-folate supplementation, 1 SR, HIC and LMICImproved birth outcomes: reduced risk of early-preterm (<34 wk) birth (RR 0.51, 95% CI 0.29 to 0.91; N = 3743 in 5 studies) and reduced risk of low birth weight (RR 0.83, 95% CI 0.73 to 0.94; N = 4645 in 5 studies) in areas with high malarial burden only
Improved infant iron stores: increased infant (<6 mo) serum ferritin concentration (MD 11.00 µg/L, 95% CI 4.37 to 17.63; N = 197 in 1 study)
MMN supplementation, 2 SRs, HIC and LMICImproved birth outcomes: reduced risk of SGA birth (RR 0.91, 95% CI 0.84 to 0.97; N = 67 036 in 14 studies), low birth weight (RR 0.88, 95% CI 0.85 to 0.90; N = 70 044 in 15 studies), and preterm birth in underweight (BMI <20) mothers (RR 0.85, 95% CI 0.80 to 0.90; 4 studies)
Improved growth during gestation: increased head circumference (SMD 0.08, 95% CI 0.00 to 0.15; N = 2692 in 4 studies)
Nonsignificant effects: mental development scores at 6 mo (MD −0.02, 95% CI −6.78 to 6.74; N = 770 in 1 study) and 12 mo (MD 1.21, 95% CI −5.06 to 7.48; N = 744 in 1 study) and psychomotor development scores at 6 mo (MD −0.16, 95% CI −3.91 to 3.59; N = 770 in 1 study) and 12 mo (MD 0.34, 95% CI −2.73 to 3.41; N = 744 in 1 study)
Balanced protein-energy supplementation, 1 SR, HIC and LMICImproved birth outcomes: reduced risk of low birth weight (RR 0.68, 95% CI 0.51 to 0.92; N = 522 in 5 studies) and SGA birth (RR 0.66, 95% CI 0.49 to 0.89; N = 5250 in 9 studies)
Augmented linear growth during gestation: increased birth length (MD 0.16 cm, 95% CI 0.02 to 0.31; N = 3698 in 7 studies)
Nonsignificant effects: mental development scores at 1 y (MD −0.74, 95% CI −1.95 to 0.47; N = 411 in 1 study)
  • CI, confidence interval; HIC, high-income country; MD, mean difference; RR, risk ratio; SMD, standard mean difference; SR, systematic review.