After accommodating the pregnancy for an average of 40 weeks, the uterus expels the fetus, the placenta and the membranes through the birth canal in a process named parturition. The absolute sequence of events that trigger and sustain human parturition are not yet fully clarified. Evidence suggests that spontaneous preterm and term labor seem to share a common inflammatory pathway. However, there are several other factors being involved in the initiation of human parturition. Placental corticotropin releasing hormone production seems to serve as a placental clock that might be set to ring earlier or later determining the duration of pregnancy and timing of labor. Estrogens do not cause contractions but their properties seem to capacitate uterus to coordinate and enhance contractions. Cytokines, prostaglandins, nitric oxide and steroids seem also to induce ripening by mediating remodeling of the extracellular matrix and collagen. Infection and microbe invasion resulting in chorioamnionitis also represents a common cause of early preterm labour. This review provides an overview of all these factors considered to be implicated in the initiation of human parturition.
Only 2 of 4 Rotterdam phenotypes, identical with those of the classic PCOS definition, have excess cardiometabolic risk. These need to be treated to prevent CVD events.
Studying the different check points of the VEGF pathway, we conclude that targeting calcium pathways could be beneficial for the vascular permeability control in an OHSS animal model.
<b><i>Purpose:</i></b> To assess whether open and closed vitrification protocols are equally effective for sibling-oocyte cycles when performing blastocyst embryo transfers. <b><i>Materials and Methods:</i></b> A prospective study was set up comparing the open and the closed vitrification techniques in oocyte recipients sharing sibling oocytes between 2014 and 2016. Sibling oocytes were randomly and equally assigned into the closed group (oocytes vitrified in a closed system) or the open group (oocytes vitrified in an open system). Intracytoplasmic sperm injection was performed on all cases. Embryo transfers were performed on day 5. Power analysis calculation showed that 94 cycles would be needed for each group in the study in order to achieve statistical significance at a 5% level with power 80%. <b><i>Results:</i></b> The final number of donors included was 95. A total of 190 recipients matched with their donors were included in the study. There was no difference in the mean number of oocytes vitrified with the closed or the open system (8.26 ± 2.54 vs. 8.31 ± 2.57). No significant difference was observed between the 2 groups regarding survival rate, fertilization rate, cleavage rate, top-quality embryos on day 3, blastocyst rate, and top-quality blastocyst rate. Moreover, no statistically significant difference in the b-human chorionic gonadotropin-positive rate, clinical pregnancy rate per cycle, implantation rate, ongoing pregnancy rate, and live birth rate between closed and open groups. <b><i>Conclusion:</i></b> Οpen and closed vitrification protocols are equally effective for sibling-oocyte cycles.
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