The involvement of the immune system in the process of implantation and its modulation as a therapeutic line in these alterations, failure of implantation and repetition abortion are controversial and make it necessary to conduct clinical studies properly led and with a study population chosen by strict criteria in order to better understand the involvement of the different innate and adaptive immune mechanisms in the field of reproductive medicine and especially in clinically expressed failures recurrent implantation failure and recurrent abortions.

A prospective pilot study is proposed in patients with recurrent implantation failure and recurrent abortions undergoing assisted reproductive techniques.

The main objective of this study is to determine the involvement of key effectors of innate immune response in the endometrium that induces a pro-inflammatory response, and to be able to know in particular what is the distribution of KIR receptors in the uNK and the HLA-C typing in patient-mother, egg/semen donors, male-father, abortive remains, live newborns.

To this end, the distribution of KIR and HLA-C receptors will be studied two arms/patient groups, divided from a population chosen according to inclusion/exclusion criteria:

• Group I: group recurrent abortions.
• Group II: group recurrent implementation failure. The study population will include subjects of older age (aged between 18 and 37 years) who will be divided into 2 total Study Arms N x 200 (n x 100 for each arm).

Inclusion Criteria in recurrent implantation failure:

• Body mass index between 19 and 27 kg/m2
• Patients with 3 or more IVF failures following transfer of good quality embryos or with 2 or more failures following embryo transfer in egg donation cycles.
• At least one embryo transfer is required to have been made in a blastocyst state (embryo on day 5) and with the current partner/donor.
• Study of normal karitype..
• Normal thrombophilia study.
• Vaginal exudate (Chlamydia, ureaplasma) normal
• Normal immune study.
• No hormone treatment in the two months prior to inclusion in the study.

Inclusión criteria in recurrent abortion:

• Body mass index between 19 and 27 kg/m2
• Patients with 3 or more recurrent abortions, natural gestations or after transfer of good quality embryos (own or ovodonation)
• Study of normal karitype.
• Normal thrombophilia study.
• Vaginal exudate (Chlamydia, ureaplasma) normal
• Normal immune study.
• No hormone treatment in the two months prior to inclusion in the study.

Exclusion Criteria:

• Pregnant or lactating women.
• They cannot offer cooperation.
• Participation in a study or clinical trial during the 3 months prior to inclusion.
• Patients with fibromes.
• Patients with PCOS.
• Patients with some genetic alteration (altered karitype, cystic fibrosis, multiple sclerosis, rheumatoid arthritis...)
• Patients chronic infectious disease.
• Patients in maintenance treatment with immunosuppressants.
• Patients who have received systemic corticosteroids in the last 4 weeks.
• Patients diagnosed with chronic lymphoproliferative disease.

Women with a history of recurrent abortion or recurrent implantation failure

Women with a history of recurrent abortion (more than 3 idiopathic involuntary abortions) or recurrent implantation failure (more than 3 failures of IVF cycles with good quality embryos or more 2 failures in cycles with donor eggs) that will undergo a cycle assisted reproduction