Predicting fetal death by measuring oestrogen:creatinine ratios on early morning samples of urine.

Total oestrogens were measured, on a creatinine basis, by a fully automated method in 75 000 early morning specimens of urine from 5429 women. Among the 5241 pregnancies in which the oestrogen:creatinine ratio was normal there were 11 fetal deaths (0-21%). But there were 57 fetal deaths (30-3%) among 188 patients with ratios below the fifth centile. When delivery took place before the ratio decrease to below the fifth centile a live baby was born in every one of 59 pregnancies. Apart from its effectiveness in predicting fetal death, the test has a high degree of precision and can be performed swiftly, and cheaply. For these reasons the assessment of fetoplacental function by measuring the urinary:creatinine ratio could become a convenient and inexpensive part of antenatal care that could be extended to every pregnant woman without making many further demands on obstetricians' time.