Use of the estrogen/creatinine ratio and the “estrogen index” for screening of normal and “high-risk” pregnancy

Abstract

The estrogen/creatinine ratio and the “estrogen index” were determined in random voided urines from 483 normal pregnancies and 80 high-risk pregnancies. When both ratios were used, they predicted 70.5 per cent of low-birth-weight infants in apparently normal pregnancies. Estrogen levels detected 84.6 per cent of low-birth-weight infants when determined prior to the twenty-eighth week of gestation and 60.6, 59.1, and 56.3 per cent, respectively, at the twenty-eighth to thirty-second weeks, thirty-second to thirty-sixth weeks, and thirty-sixth week to term. Values below the tenth percentile at any time in pregnancy were followed by delivery of low-birth-weight babies in 43.6 per cent of patients with a low estrogen/creatinine ratio and 41.3 per cent of those with a low estrogen index. Estrogen ratios could not predict the future occurrence of prematurity, toxemia, or abruptio placentae. However, the perinatal mortality rate was 13.5 times greater (2.2/1,000 vs. 29.7/1,000) in patients with estrogen values below the tenth percentile.