Effect of a membrane depolarization on the human chorionic gonadotropin (hCG) and placental lactogen (hPL) release by placental explants

Abstract

Serum human placental lactogen (HPL) was measured by a radioimmunoassay technique in 7,443 samples obtained from 1,814 pregnant women beyond their twentieth week of gestation. The pattern demonstrated by the 3,014 samples from 804 normal women confirmed the fact that abnormally low HPL values can be defined by the F-D zone (<4 μg per milliliter after 30 weeks of gestation) and these rarely occur (1.4 per cent) in normal pregnancies. The patterns in pregnancies complicated by Rh sensitization (38 women; 156 samples), diabetes mellitus (23 women; 248 samples), and hypertensive toxemia (949 women; 4,025 samples) were also studied. The major factor which appears to lower HPL values is vascular disease. In the toxemia group HPL values were more frequently depressed with multiparity and severe hypertension (BP>160/110). There was no relation noted between the presence of albuminuria in primiparous toxemia and the level of HPL in maternal serum. It would appear that the measurement of HPL in women with potential vascular disease will help to identify those with concurrent abnormal placental function.