Folic acid, which is the synthetic form of the vitamin folate, is critical both in pre-and peri-conception. Deficiencies in folic acid may cause neural tube defects (NTDs). Women who had 0.4 mg of folic acid in their systems due to supplementing 3 months before childbirth significantly reduced the risk of NTDs. More than 80 countries use fortification of certain foods with folic acid as a measure to decrease the rate of NTDs. Vitamins C and E The combination of vitamin E and vitamin C supplemented to pregnant women does not appear to be efficacious for reducing risk of stillbirth, neonatal death, preterm birth, preeclampsia or any other maternal or infant outcomes, either in healthy women or those considered at risk for pregnancy complications. Antioxidant vitamins as dietary supplements had been proposed as having benefits if consumed during pregnancy. For the combination of vitamin E with vitamin C supplemented to pregnant women, a Cochrane review of 21 clinical trials concluded that the data do not support vitamin E supplementation – majority of trials alpha-tocopherol at 400 IU/day plus vitamin C at 1000 mg/day – as being efficacious for reducing risk of stillbirth, neonatal death, preterm birth, preeclampsia or any other maternal or infant outcomes, either in healthy women or those considered at risk for pregnancy complications. The review identified only three small trials in which vitamin E was supplemented without co-supplementation with vitamin C. None of these trials reported any clinically meaningful information. A second Cochrane review of 29 trials, published same year, reported on the same combination trials but added analysis of trials with vitamin C alone. The conclusion was that the data do not support routine vitamin C supplementation alone or in combination with other supplements for the prevention of fetal or neonatal death, poor fetal growth, preterm birth or preeclampsia. Vitamin B12 For vitamin B12, the U.S. Recommended Dietary Allowance (RDA) for pregnancy is 2.6 µg/day, for lactation 2.8 µg/day. Determination of these values was based on RDA of 2.4 µg/day for non-pregnant women plus what will be transferred to the fetus during pregnancy and what will be delivered in breast milk. However, looking at the same scientific evidence, the European Food Safety Authority (EFSA) sets adequate intake (AI) at 4.5μg/day for pregnancy and 5.0 μg/day for lactation. Low maternal vitamin B12, defined as serum concentration less than 148 pmol/L, increases the risk of miscarriage, newborn low birth