Urinary estriols in diabetic pregnancy: a reappraisal

The clinical usefulness of serial urinary estriols was tested in 138 insulin-dependent diabetic pregnant women. No action was taken on an estriol drop if fetal well-being was demonstrated by a reactive nonstress test and/or negative contraction stress test within 24 hours. Of 3085 estriol values, a greater than or equal to 40% estriol drop, confirmed by a greater than or equal to 40% decrease in the estriol-creatine ratio, was observed in 21 tests. In only two of these tests, was fetal distress indicated by a nonstress test or contraction stress test. A significant linear correlation was demonstrated between the mean level of estriol excretion and birth weight, placental weight, and fetal abdominal circumference measured by ultrasound. Chronically low estriol excretion (less than 12 mg per 24 hours at greater than 36 weeks' gestation) related to smaller placentas but not to fetal jeopardy.