The role of human placental lactogen assays in antepartum fetal assessment.

To determine the role of hPL radioimmunoassays in screening for fetal assessment in normal and hypertensive pregnancies the results of 148 pregnancies were examined by measuring the specificity and sensitivity of the test for prospectively defined fetal conditions. Values of hPL were considered abnormal if they were below the tenth percentile for the range of values derived from pregnancies with a normal fetal outcome ( less than 3.8 microgram/ml). The specificity of the test was 95% but it would have correctly predicted a normal fetal outcome in only 85% of pregnancies. The test varied in its ability to accurately predict abnormal fetal outcome; the sensitivity for the single stillbirth and for cases of fetal jeopardy was 87%, whereas for IUGR the result was 41%. There was a significant difference between hPL values associated with fetal jeopardy and uncomplicated IUGR (p less than 0.01). The frequency of sampling and the application of these results to the prospective screening of normal and hypertensive pregnancies is discussed and it is concluded that hPL assays have a limited but specific role in antepartum evaluation. Screening should be reserved for pregnancies associated with hypertension to exclude the risk of stillbirth and fetal jeopardy occurring specifically in the IUGR fetus.