Screening for multiple pregnancy. Determination of human chorionic gonadotropin (hCG), alpha-fetoprotein (alpha-FP) and human placental lactogen (hPL) in blood during the second trimester of pregnancy.

The value of single determinations of serum hCG, hPL, and alpha FP 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.