Second-trimester maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated oestriol after early transvaginal multifetal pregnancy reduction

Maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), and unconjugated oestriol (UE₃) are used as second-trimester screening markers for the detection of various fetal abnormalities. Previous studies have suggested that second-trimester MSAFP is consistently elevated after late first-trimester transabdominal multifetal pregnancy reduction (MFPR). The present study was undertaken to evaluate the levels of all three markers after early transvaginal MFPR. Maternal serum was examined for MSAFP, hCG, and UE₃ at 16-18 weeks' gestation in 28 patients who underwent transvaginal MFPR at approximately 10 weeks' gestation. The mean interval between the reduction procedure and the screening test was 7.2 ± 0.9 weeks. The mean MSAFP value in 24 patients carrying viable twins was 2.49 ± 0.99 multiples of the median (MOM). Two patients had elevated MSAFP values: one in association with omphalocoele and the other in relation to an adverse pregnancy outcome. All but two patients had normal hCG values (mean 1.98 ± 1.26 MOM). Two cases with elevated hCG were associated with an adverse pregnancy outcome. Unconjugated oestriol values were within the normal range in all patients (mean 1.69 ± 0.61 MOM). These results suggest that early transvaginal MFPR, at approximately 10 weeks' gestation, does not appear to influence second-trimester MSAFP, hCG, and UE₃ levels. The values of these markers may therefore be interpreted by using the same criteria as those for the general obstetric population.