The transplacental passage of prednisolone in pregnancies complicated by early-onset HELLP syndrome

During pregnancy the placental 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) enzyme inactivates prednisolone by interconversion into prednisone, protecting the fetus from high levels of prednisolone. Recent reports suggest decreased placental 11β-HSD2 activity in pregnancies complicated by preeclampsia. The purpose of our investigation was to study the transplacental passage of prednisolone in patients suffering from early preterm HELLP syndrome, a severe complication of preeclampsia. We examined the maternal and umbilical cord plasma concentration of prednisolone in nine women receiving 50 mg of prednisolone twice a day. Samples were obtained during caesarean section at a gestational age between 27 and 31 weeks. Mean fetal concentration was 10-fold lower as compared to maternal prednisolone concentration (mean ± SD 52.8 nmol/L ± 27.0 vs. 477.5 nmol/L ± 300, p < 0.01). A significant correlation was found between the last dose of prednisolone to delivery interval and the fetal prednisone concentration (Spearman's correlation coefficient r = −0.946, p < 0.000). Our data demonstrate unimpaired placental 11β-HSD2 activity in patients suffering from HELLP syndrome at early gestational age as shown by both a 10-fold lower fetal prednisolone concentration as compared to the mother and a strong correlation between the last dose of prednisolone to delivery interval and the fetal prednisone concentration. Prednisolone may therefore have less effect on the fetus than betamethasone or dexamethasone.