Total maternal urinary estrogen excretion and estrogen/creatinine ratio as placental function tests.

Five hundred patients with complications of pregnancy who were thought to be at risk of intrauterine growth retardation had serial paired maternal 24-hour total urinary estrogen levels measured and random estrogen/creatinine ratios determined until within three days of delivery. The correlation between the random estrogen/creatinine ratio and the incidence of intrauterine growth retardation, presence of fetal distress in labor and a low Apgar score was found to be as good as the correlation between total maternal urinary estrogen excretion levels and fetal weight and status.