Homocysteine and methylmalonic acid as indicators of folate and vitamin B-12 deficiency in pregnancy

Deficiency of folate during pregnancy is associated with megaloblastic anae mia. Lower levels of folate and vitamin B-12 have been reported in mothers whose offspring had neural tube defects compared to unaffected controls. In creased methylmalonic acid levels are a sensitive indicator of mild vitamin B-12 deficiency and elevated homocysteine levels denote vitamin B-12 or fo late deficiency. We have investigated the relationship between serum concen tration of total homocysteine, methylmalonic acid, vitamin B-12 and folate in pregnancy. A significant inverse correlation was found between homocyste ine and red cell folate and, to a lesser extent, serum folate. In addition, a significant inverse correlation was found between methylmalonic acid and vitamin B-12, No significant relationship was found between homocysteine a nd vitamin B-12. The relationship between red cell folate and serum folate and homocysteine may be useful for detecting borderline folate deficiency i n pregnancy and indicate pregnancies at risk of neural tube defect. These s ensitive assays are useful tools for the further investigation of folate vi tamin B-12 and metabolism in normal and abnormal pregnancy.