The value of single determinations of serum hCG, hPL, and αFP for the detection of multiple pregnancy was investigated in a consecutive series of 992 women between the 14th and 24th week of pregnancy. With the 90th percentile as referent value, all twin pregnancies (n = 10) were detected by the combined results of the three determinations. Considered separately, hPL proved to be the most useful indicator of multiple gestation; the sensitivity of hPL alone was 70% and the predictive value of hPL concentrations above the 90th percentile was 8.1.
