Blocking Folic Acid Doubles Risk of Malformations

Photo: Pregnant woman looking at her belly

Certain drugs should be avoided
during pregnancy, researchers say;

This conclusion was reached by a team of epidemiologists, paediatricians, clinical pharmacologists, obstetricians and gynaecologists who examined birth and abortion data collected in Israel between 1998 and 2007.

The study obtained medication data from pregnant mothers and drew information from 84,832 babies born in Israel. "After studying the data, we concluded that first trimester exposure to folic acid antagonists is associated with increased risk for neural tube, cardiovascular and urinary tract defects," according to the principal investigator Rafael Gorodischer.

Healthcare professionals now encourage women to take folic acid supplements or eat food fortified with folic acid if they are planning to get pregnant, as well as during early pregnancy because there is clear evidence that this reduces the risk of any resulting baby having neural tube defects and possibly other birth defects (congenital malformations).

The team considered the effects of two groups of medications on pregnancy. Each group consists of drugs that prevent folic acid working in the body. One group (dihydrofolate reductase inhibitors) prevents folate from being converted into its active metabolites and includes trimethoprim (antibiotic), sulfasalazine (for ulcerative colitis) and methotrexate (chemotherapeutic). The other medications are known to lower serum and tissue concentrations of folate by various mechanisms, and include antiepileptics (carbamazepine, phenytoin, lamotrigine, primidone, valproic acid and phenobarbital) and cholestyramine (reduces cholesterol).

The study shows that exposure to folic acid antagonists in the first trimester of pregnancy more than doubles the risk of congenital malformations in the fetus, and that neural tube defects, such as spina bifida and malformations of the brain, increase by more than six-fold after exposure to these antagonists, the researchers say. "Clinicians should try to avoid the use of these drugs whenever possible in women contemplating pregnancy," concludes Gorodischer.; Source: American Associates, Ben-Gurion University of the Negev