A prospective study of three biochemical fetoplacental tests: serum human placental lactogen, pregnancy-specific beta 1-glycoprotein, and urinary estrogens, and their relationship to placental insufficiency

Abstract

The relationship between abnormal biochemical fetoplacental test results and placental insufficiency was studied in a group of high-risk obstetric patients. The urinary estrogen: creatinine ratio and serum human placental lactogen (hPL) and pregnancy-specific beta 1-glycoprotein (SP1) were measured in more than 1,600 patients. Fifty-one patients were found to have abnormal biochemical results, and the placentas from these patients were sent for the assessment of placental insufficiency by pathologic examination, which was expressed as a placental insufficiency score. Low hPL was found to be the best biochemical indicator of placental insufficiency, and 84% of the patients with a low level of hPL had an elevated placental insufficiency score. The combination of low levels of hPL and urinary estrogen was found to be the best indicator of placental insufficiency associated with retarded intrauterine growth, and 83% of the patients who had low results in both of these tests had elevated placental insufficiency scores and were delivered of light-for-dates infants. The measurement of SP1 was found to be of limited value in detecting retarded growth, but patients with low SP1 values showed an increased incidence of fetal hypoxia. Attention is drawn to the fact that the discrepancies that occur in the various estimations are not necessarily due to artifact, and specific pathologic processes which could account for some of the anomalous results are identified.