Pharmacokinetics and analysis of the placental distribution of betamethasone in twin pregnancies

Abstract

Multiple pregnancies are associated with high morbidity and mortality rates related to prematurity. In single pregnancies, at the imminence of preterm delivery,antenatal corticosteroid therapy is recommended, aimingreducing the harmful consequences of this birth. However, in the multiple pregnancies, prescribing the same corticosteroids does not seem to benefit in similar magnitude. It is exposed that pharmacokinetics and placentaltransfer of corticosteroids is different in these pregnancies, but there are few clinical studies that have evaluatedespecially, if we consider the several forms of chorionicity and amnionicity of the twins. The present project the aim of this study is to compare the pharmacokinetics of the betamethasone in single pregnancy, with the twinpregnancy at risk of preterm labor, evaluating the volume of distribution, half-life, clearance and placental transfer of the drug. Patients who complete the inclusion criteria after antenatal administration of intramuscularbetamethasone (every 24 hours, for two consecutive days, total of 2 doses), will be collected a serial of samples of maternal blood for pharmacokinetic analysis after the second dose. If there is a gestation resolution, bloodsamples will be collected from the cord umbilical, intervillous space and amniotic fluid for placental transferanalysis. The sample estimate for the pharmacokinetic evaluation was 10 patients in each group (single and twin pregnancies). The tests for analysis statistics are Mann-Whitney and Kruskal-Wallis, when necessary. (AU)