Folate and human reproduction

http://folk.uib.no/mfapu/Pages/papers%20pdf/2003/el-khairy_2003_ajcn_77.467.pdf

Plasma total cysteine, pregnancy complications, and adverse pregnancy outcomes: the Hordaland Homocysteine Study

An elevated circulating level of total homocysteine (tHcy) is a powerful and independent risk factor for vascular disease as well as an indicator of folate deficiency. Both infants with neural tube defects and their mothers have altered homocysteine metabolism, and numerous studies have pointed to a relation between plasma tHcy and both pregnancy complications and a compromised neonatal outcome. This analysis examined associations between tHcy and reproductive outcomes in 5883 women 40 to 42 years of age who were enrolled in the Hordaland Homocysteine Study conducted in Norway during 1992–1993. The findings were compared with those of 14,492 pregnancies in the same women during the years 1967–1996. Women with the highest tHcy levels smoked more than the others, drank more coffee, were less educated, and used fewer vitamin supplements. In addition, they tended to have their children at a younger age than women with lower tHcy values. Preeclampsia correlated with the tHcy level to a highly significant degree, particularly in women who delivered prematurely. Controlling for blood pressure weakened this association, but for pregnancies lasting less than 37 weeks, the odds ratio (OR) for preeclampsia in women with plasma tHcy in the upper quartile was 4.42. The risk of placental abruption was elevated in women with a high tHcy level (OR, 3.13), and elevations also correlated with premature deliveries before 37 weeks’ gestation and before 32 weeks’ gestation. Low birth weight correlated strongly with relatively high tHcy values. After 1970 the OR for very low birth weight ( Am J Clin Nutr 2000;71:962–968

Plasma Total Homocysteine, Pregnancy Complications, and Adverse Pregnancy Outcomes: The Hordaland Homocysteine Study

The importance of folate in reproduction can be appreciated by considering that the existence of the vitamin was first suspected from efforts to explain a potentially fatal megaloblastic anemia in young pregnant women in India. Today, low maternal folate status during pregnancy and lactation remains a significant cause of maternal morbidity in some communities. The folate status of the neonate tends to be protected at the expense of maternal stores; nevertheless, there is mounting evidence that inadequate maternal folate status during pregnancy may lead to low infant birthweight, thereby conferring risk of developmental and long-term adverse health outcomes. Moreover, folate-related anemia during childhood and adolescence might predispose children to further infections and disease. The role of folic acid in prevention of neural tube defects (NTD) is now established, and several studies suggest that this protection may extend to some other birth defects. In terms of maternal health, clinical vitamin B12 deficiency may be a cause of infertility or recurrent spontaneous abortion. Starting pregnancy with an inadequate vitamin B12 status may increase risk of birth defects such as NTD, and may contribute to preterm delivery, although this needs further evaluation. Furthermore, inadequate vitamin B12 status in the mother may lead to frank deficiency in the infant if sufficient fetal stores of vitamin B12 are not laid down during pregnancy or are not available in breastmilk. However, the implications of starting pregnancy and lactation with low vitamin B12 status have not been sufficiently researched.

Tow Siang Hwa

Papers

Abruptio placentae and defective folate metabolism in singapore women