Placental transfer of clarithromycin in human pregnancies with preterm premature rupture of membranes

Aim: The aim of this study was to evaluate the transplacental transfer of clarithromycin, which was used in the treatment of preterm premature rupture of membranes (PPROM) in human pregnancies, by comparing umbilical cord and maternal serum clarithromycin concentrations. Methods: Singleton pregnant women with PPROM (<34 weeks) were prospectively enrolled between April 2009 and January 2011. The diagnosis of PPROM was made with vaginal pooling, leakage, nitrazine, and Amnisure tests. The women were managed expectantly with bed rest, corticosteroids, and a triple antibiotic combination including ceftriaxone, clindamycin, and clarithromycin. Amniocentesis was offered, and culture for aerobe/anaerobe and mycoplasma was performed. After delivery, blood was drawn from the mother's antecubital and umbilical cord veins. Clarithromycin concentrations were measured using liquid chromatography-tandem mass spectrometry. The percentage and correlation between cord and maternal serum clarithromycin concentrations were calculated. Logistic regression analysis was performed to investigate the factors related to the cord and maternal serum clarithromycin concentration percentage. Results: A total of 34 cord-maternal serum pairs were included in the final analysis. The mean cord-maternal serum clarithromycin concentration percentage was 7.93 +/- 0.9%. There was a good correlation between cord serum and maternal serum clarithromycin concentration (r = 0.795, P < 0.001). The cord-maternal serum clarithromycin concentration percentage significantly increased according to advancing gestation (P < 0.001). Conclusions: Our data showed that the mean placental transfer of clarithromycin is approximately 8% and dependent on gestational age.