Results
The 26 pregnant women were divided into three groups: singleton pregnancies (n=9), DC twin pregnancies (n=9) and MC twin pregnancies (n=8). The groups of pregnant women were compared regarding maternal age, body mass index and gestational age at childbirth. There were no significant differences among these features for the three groups. The demographic and laboratory test results of the pregnant women are presented in Table 1. Serum albumin concentration was significantly higher in MC twin pregnancies compared to singleton and DC twin pregnancies. On the other hand, the plasmatic urea concentration was significantly lower in MC twin pregnancies.
The median curves of plasma BET concentration versus time for the three groups were determined during the 24h after a single intramuscular dose of 12mg of BET sodium phosphate and BET acetate (Figure 1). Table 2 lists the pharmacokinetic parameters, demonstrating differences among the groups of pregnant women. The AUC0-∞ and CL/F were significantly lower and higher, respectively, in DC twin pregnancies compared to singleton and MC twin pregnancies. On the other hand, Cmax, Tmax and Vd/F were not significatively different among the groups. Vd/F (p=0.02; r=0.4530) was correlated to body mass index, but not to any other demographic or biochemical data (Figure 2).
Figure 3 shows preliminary data on the BET placental transfer, expressed by the umbilical cord to maternal vein concentration ratio and intervillous space to maternal vein concentration ratio.