Plasma and red cell folate in newborn twins and their mothers in relation to gestational age.

Plasma and red blood cell folate concentrations (Lactobacillus casei activity) have been studied in 56 newborn twins and in 26 of their mothers, and in a control group consisting of 186 singletons and 155 of their mothers. The duration of the pregnancies ranged from 30-40 weeks. Iron, but no folic acid supplementation was given during pregnancy. The plasma and red cell folate concentrations in the twin mothers were at all stages of pregnancy similar to those observed in women with single pregnancies having an adequate folate intake. The twins had plasma folate concentrations similar to singletons at all gestational ages. Their red cell folate concentrations were lower than in singletons until 37 weeks of gestation, while the values were similar at term, indicating an increased transfer of folate to the twins during the last week of pregnancy. The smaller of the twins had similar plasma folate concentrations and lower red cell folate concentrations compared to the bigger one. At 30-32 weeks of pregnancy twin mothers had lower Hb, RBC and VPRC-values than women with single pregnancies. Twin mothers, delivering at 38-40 weeks of pregnancy, had values corresponding to those of single pregnancy women, probably indicating a recovery from a physiological lowering of the blood values. The twins had a similar Hb, lower RBC and higher MCV and reticulocyte values compared to singletons, possibly indicating a more active erythropoiesis in the twins. Folic acid supplementation is not recommended as a routine in twin pregnancies in this population. Twins delivered before term should be ensured an adequate folate intake.