Hyperhomocystinemia poses pregnancy challenge. (Normalized by Folate Administration).

BIG SKY, MONT. -- Elevated plasma homocysteine is associated with serious complications in pregnancy, Dr. Jodi Schucker said at an ob.gyn. update sponsored by the Geisinger Health System.

Hyperhomocystinemia is an expression of a common inherited thrombophilia that results from a defect in either the methylene tetrahydrofolate reductase gene or the cystathionine [beta]synthetase gene. It's important to routinely search for these abnormalities as well as for the other leading inherited thrombophilias--factor V Leiden mutation, prothrombin gene mutations, antithrombin III deficiency, protein S deficiency and protein C deficiency--in all women with a history of venous thromboembolism who are pregnant or planning pregnancy.

A search for the most common inherited thrombophilias is warranted even in women without prior venous thromboembolism, provided that they have a history of poor pregnancy outcome involving abruption, severe preeclampsia with onset prior to 34 weeks, second- or third-trimester pregnancy loss, or severe intrauterine growth retardation, added Dr. Schucker, a perinatologist at Geisinger Medical Center, Danville, Pa.

If a genetic deficiency in either methylene tetrahydrofolate reductase or cystathionine [beta]-synthetase is identified, it needs to be followed up with a fasting plasma homocysteine level. Some patients with the genetic deficiency have a normal homocysteine level, and their risk in pregnancy appears to be like that of normal women.

A homocysteine level in excess of 12 [micro]mol/L in pregnancy or 16 [micro]mol/L in a nonpregnant woman confirms the presence of a clinically important inherited thrombophilia. The threshold for hyperhomocysteine drops in pregnancy because the reduced albumin levels in pregnancy ...