Dietary and serum folate: their influence on the outcome of pregnancy.

We examined the influence of folate intake from diet and supplements b y 28 wk of gestation and third trimester circulating concentrations of serum folate on the outcome of pregnancy in women from Camden, NJ. Mean daily folate intake by week 28 included both dietary and supplemental folate obtained prospectively in 832 women. Circulating concentrations of serum folate as well as serum vitamin B-12 were assayed at 28 wk of gestation (+/- 2 wk) by radioimmunoassay. The outcomes of interest included preterm delivery (<37 wk) and infants with low birth weight (<2500 g). Mean folate intake was significantly correlated with circulating concentrations of serum folate (r=0.17, P<0.001). Women with a low mean daily folate intake (</-240 microgram/d) had an approximately twofold greater risk of preterm delivery and infant low birth weight after maternal characteristics, energy intake, and other correlated nutrients were controlled for. Lower concentrations of serum folate at week 28 were also associated with a greater risk of preterm delivery and low birth weight.