Second trimester maternal serum alpha-fetoprotein (MSAFP) as predictor of fetal hemoglobin Bart's disease.

OBJECTIVE

The objective of this study is to evaluate the efficacy of maternal serum alpha-fetoprotein (MSAFP) levels in predicting hemoglobin (Hb) Bart's fetus.

MATERIALS AND

METHODS

A total of 199 pregnancies at risk of fetal Hb Bart's disease at 18 to 22 weeks were enrolled. Before performing cordocentesis for the Hb typing analysis, the MSAFP levels were analyzed, and sonographic markers (middle cerebral artery peak systolic velocity, cardiothoracic ratio and placental thickness) were measured. The detection rates of MSAFP and the sonographic markers in predicting fetuses affected by Hb Bart's disease were evaluated.

RESULTS

The MSAFP levels were significantly higher in pregnant women carrying affected fetuses (47 cases) than in those with unaffected fetuses (2.09 MoM vs 1.18 MoM, P < 0.001). MSAFP as a single marker effectively predicted fetal Hb Bart's disease (area under curve receiver operating characteristic 0.832, 95% CI 0.752-0.911), with 87.2% sensitivity and 74.5% specificity using a cutoff value greater than 1.50 MoM. A combination of MSAFP with sonographic markers gave detection rates in the range of 91.5% to 100%.

CONCLUSION

Second trimester MSAFP levels are significantly higher in pregnancies with Hb Bart's fetus. MSAFP as a single marker is relatively effective in Hb Bart's prenatal screening. A high detection rate is achieved when MSAFP is used in combination with sonographic markers.