Prenatal strategies for reducing severe thalassemia in pregnancy

To describe the prenatal strategy in reducing new cases of severe thalassemia at Maharaj Nakorn Chiang Mai Hospital. The study design involved a prospective descriptive analysis set in Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University.

Pregnant women attending antenatal clinic.

The strategy included: (1) carrier identification by retrospective (history review) and prospective screening program; (2) the couples at risk were counseled and offered cordocentesis; (3) analysis of fetal blood with high performance liquid chromatography (HPLC) or electrophoresis; and (4) counseling for termination of pregnancy in case of affected fetus. The prospective screening consisted of testing for a carrier by a simple erythrocyte osmotic fragility test (EOFT) in women with no risk and testing the husbands of the women with abnormal tests. A pregnancy in which both of the couple were carriers was considered a risk.

Cordocentesis was performed in 554 pregnancies at risk, 252 and 302 from retrospective and prospective screening, respectively. Sixty of 252 of the first group had severe thalassemia. In the prospective screening program of 12 680 women, 459 risk couples were identified, 302 pregnancies underwent cordocentesis and 53 (17.5%) had severe thalassemia. This strategy enabled us to identify 113 cases of severe thalassemia (Hb Bart's; 60, beta-thal entities; 53) from 554 cases at risk.

The strategy proves valuable in the control of severe thalassemia. This extensive experience suggests the strategy be considered an effective way in the control of severe thalassemia in high prevalence areas.