The implanting blastocyst must appose and adhere to the endometrial epithelium and, subsequently, invade it. Locally regulated uterine epithelial apoptosis induced by the embryo is a crucial step of the epithelial invasion in rodents. To address the physiological relevance of this process in humans, we investigated the effect of single human blastocysts on the regulation of apoptosis in cultured human endometrial epithelial cells (hEEC) in both apposition and adhesion phases of implantation. Here, we report a co-ordinated embryonic regulation of hEEC apoptosis. In the apposition phase, the presence of a blastocyst rescues hEEC from the apoptotic pathway. However, when the human blastocyst adheres to the hEEC monolayer, it induces a paracrine apoptotic reaction. Fas ligand (Fas-L) was present at the embryonic trophoectoderm. Fas was localized at the apical cell surface of hEEC, and flow cytometry revealed that 60% of hEEC express Fas. Neutralizing adhesion assays revealed that the Fas/Fas-L death system may be an important mechanism to cross the epithelial barrier, which is crucial for embryonic adhesion, and the manipulation of this system could have potential clinical implications as an interceptive mechanism.

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Both types of biopsies showed similar high concordance rates with whole blastocyst results. Therefore, regarding the confirmation rates shown in this work, day-3 embryo biopsies can be representative of the whole embryo and both types of biopsy can be used for clinical analysis in PGS following the described array-CGH protocol.

Purpose To investigate neonatal malformation, prematurity, and stillbirth in singleton and multiple pregnancies derived from different Assisted Reproductive Techniques (ART). Methods In this prospective cohort study data were collected, from private and public Spanish IVF units, during the years 2008 and 2009. During this period, 8,682 pregnancies were analysed from the initial 14,119 pregnancies reported. Pregnancies included in the study derived from IUI (n=1,065), IVF (n=838), ICSI (n=5,080), FET (n=1,404) and PGD (n=295). This first analysis focuses primarily on neonatal malformation, prematurity, and stillbirth both in singleton and multiple pregnancies derived from different ART. Malformations were classified according to the WHO ICD 10 code. Results Malformations were found in 0.83 % of our newborns. No differences in malformations were observed between singletons or multiples independently of the ART used. There was a significant difference in prematurity rate among singletons depending on treatment but this association was not observed in multiple pregnancies. Stillbirth was significantly lower in singleton (0.72 %) than in multiple pregnancies (1.82 %). Conclusions The percentage of malformations observed in ART newborns was similar to the rate observed in the normally-conceived Spanish population. Multiplicity seems to be the most important factor associated with an increased incidence of newborn complications such as prematurity or stillbirth.Keywords ART . Pregnancy outcome . Perinatal outcome . Malformations . Prematurity . StillbirthCapsule This report examines the impact of Assisted Reproductive Techniques (ART) on malformation in Spain. Malformations were found in 0.83 % of newborns, similar to levels in the general Spanish birth population.

There are important positive aspects implementing a carrier genetic test in assisted reproductive technique, but controversial issues appear. Reproductive providers must be appropriately aware and follow the new guidelines.