A pathologic investigation was conducted on 100 placentas collected from pregnancies resulting from in vitro fertilization (IVF) and intrauterine embryo transfer (ET), including 70 singleton pregnancies, 20 twin pregnancies, and 10 multiple pregnancies complicated by the vanishing twin (VT) phenomenon (n = 5) or artificially reduced (n = 5). These results were compared with those for 70 spontaneous spontaneous singleton and 20 spontaneous twin pregnancies. In cases of singleton pregnancies, the incidence of abnormal placental shapes was significantly different (P < .025) in the IVF group compared to controls. A significant (P < .005) difference was also observed between these groups in terms of umbilical cord insertion. The mean distance between the cord insertion and the closest placental margin was significantly (P < .001) shorter among IVF singleton pregnancies (3.19 +/- 1.83 versus 4.62 +/- 2.23 cm). In cases of twin pregnancy, no difference was found between IVF and spontaneous pregnancy in the incidence of pregnancy complications and distribution of cord insertion. First-trimester bleeding was the only clinical sign of the disappearance of an embryo in multiple pregnancies complicated by the VT phenomenon and was not observed in multiple pregnancies artificially reduced. The present findings support the hypothesis that marginal cord insertion is secondary to oblique orientation of the blastocyst at the nidation. A larger trial is now required, analyzing the placental features from IVF pregnancies in relation to the etiology of infertility.
The purpose of this study was to evaluate, in vivo and in vitro, the influence of ritodrine and oxytocin on the placental release of human chorionic gonadotrophin (HCG) and placental lactogen (HPL). The in-vivo study was performed on maternal sera collected before and 1 h after the onset of either ritodrine treatment (50 micrograms i.v./min; administered to 15 women at risk of premature labour) or oxytocin infusion (2 mU i.v./min; administered to 21 women for acceleration of slow labour). The in-vitro study was performed on human term placental explants incubated in the presence of 4-400 ng ritodrine/ml or 15-1500 microU oxytocin/ml. HCG and HPL were measured by radioimmunoassay on maternal sera and incubation media. Maternal circulating concentrations of HCG and HPL remained unaffected after 1 h of ritodrine or oxytocin treatment. The in-vitro release of HCG and HPL by placental explants was not modified when ritodrine or oxytocin was added to the incubation media. The lack of influence of ritodrine and oxytocin on the placental secretion of HCG and HPL suggests that beta 2-adrenergic and oxytocin receptors are not involved in the releasing process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.