Urinary estrogen determination in pregnancy.

The use of urinary estrogen assay in pregnancy as a measure of fetal well-being is now widespread. Estriol is considered by many workers to be the compound of greatest importance, since both fetus and placenta appear to share in its production (1). Pregnanediol excretion, used as an index by some workers, is reputed to be produced by the placenta alone and can be normal when fetal malfunction would be indicated by the estriol values (2). However, specific methods for determining estriol, such as that of Brown (4), are too long and complex for routine use in the average hospital laboratory, which is faced with daily determinations on large numbers of specimens from a maternity unit. Some simplification has been introduced previously by estimating total estrogens, of which estriol constitutes some 80% during late pregnancy. The basic work on which most of these simplified methods is based is that of Ittrich (4), who described a shortened purification procedure followed by measurement of the estrogens by the Kober reaction (5). These methods were studied by Oakey et al. (6), who produced a method for estimating total estrogens to monitor fetal risk in pregnancy. Although an improvement on previous methods, this is still fairly laborious and involves a number of steps in which less than skilled technique can result in loss of estrogens, although internal standards were introduced to allow for this. Using this method, one skilled technician can estimate