Plasma oestriol in pregnancies complicated by diabetes mellitus

We studied the plasma oestriol concentration during increasing gestation in 192 normal pregnancies and 96 pregnancies complicated by diabetes mellitus. Among the 96 patients there were 16 established, 32 gestational, 29 'persistent' gestational and 19 either gestational or 'persistent' gestational diabetic pregnancies. Serial blood samples were collected and their concentrations of oestriol (total oestriol) determined by radioimmunoassay. The distribution of birthweights and placental weights around each gestational period was skewed to the right. Therefore, the 5th and 95th percentiles were obtained after computing a logarithmic transformation of the data. The incidence of big and small babies in all diabetic groups, except that in the gestational diabetic group, was significantly higher than that in the group of normal pregnant women. The distribution of oestriol concentrations was also skewed to the right and had to be normalized by logarithmic transformation. The oestriol profile in normal pregnancies had a wide scatter, especially after the 37th week. Serial measurements with reference to the normal oestriol profile showed a detection rate of approximately 85% for both normal and abnormal foetal outcome. There were 15% of false negative and 16% of false positive results. Results in this study indicate that serial blood oestriol measurement may be a useful additional index for foetal monitoring in pregnancies in diabetic women. Furthermore, if large scale screenings using a single estimation are performed, it is best carried out between the 33rd and 34th week of gestation.