Descriptive Analysis of Serum Immunological Markers During an Euploid Frozen Embryo Transfer in a Natural Cycle.

Descriptive Analysis of Serum Immunological Markers During an Euploid Frozen Embryo Transfer in a Natural Cycle (NC).

To describe the peripheral serum levels of the anti-inflammatory cytokines IL-4 (Interleukin-4), IL-10 (Interleukin-10), TGF-ß1 (Transforming Growth Factor beta1), the pro-inflammatory cytokines IL-17 (Interleukin-17), IFγ (Interferon Gamma) and the immune mediator PIBF (Progesterone-Induced Blocking Factor) along a single frozen euploid blastocyst transfer in a natural cycle (NC) or Hormone Replacement Therapy (HRT).

This a prospective, observational study including 40 infertile patients undergoing a "single embryo transfer" (SET). Blood samples will be drawn for Progesterone-Induced Blocking Factor (PIBF), interleukin 17 (IL-17), Interferon Gamma (IFγ), Interleukin 10 (IL-10), Interleukin 4 (IL-4) and Transforming Growth Factor beta 1 (TGF-ß1) measurement on the day of ovulation in the natural cycle (NC) or first day of progesterone in the Hormone Replacement Therapy (HRT) protocol, on the day of embryo transfer (ET) and 3 and 10 days later, coinciding with the early and late embryo invasion stages respectively. In case of pregnancy, an additional blood test for PIBF, IL-17, IFγ, IL-10, IL-4, TGF-ß1 and ßHCG (Beta-Human Chorionic Gonadotropin) will be performed at 5 weeks +/- 3 days. The study will be performed at ART Fertility Clinics and the estimated completion time will be 12 months.

Inclusion Criteria:

• Women aged 18 years to 40 years
• Having at least one good quality (grade A or B for inner mass cell and trophectoderm) day 5 or 6 chromosomally normal cryopreserved blastocyst available for transfer
• Single embryo transfer in a natural cycle (NC) or an Hormone Replacement Therapy (HRT) protocol
• Fresh ejaculate used for fertilization

Exclusion Criteria:

• Body mass index lower than 18.5 or equal or higher than 29 kg/m2
• Endometriosis or adenomyosis suspected by medical history (dysmenorrhea, dyspareunia, heavy or prolonged menstrual bleeding (> 8 days), chronic pelvic pain, catamenial rectal or bladder symptoms) or diagnosed by imaging (magnetic resonance imaging or ultrasonography)
• Uterine abnormalities
• Hydrosalpinx
• Insulin resistance or diabetes mellitus diagnosed by HbA1c 5.7 %
• Antiphospholipid syndrome
• Polycystic ovarian syndrome according to Rotterdam criteria: presence of at least two of the following: irregular cycles (< 21 or > 35 days or < 8 cycles a year), biochemical or clinical hyperandrogenism, ovarian ultrasound morphology (> 20 follicles per ovary on transvaginal scan) or Anti-mullerian hormone > 5,98 ng/ml
• History of recurrent miscarriage, defined as the loss of 2 or more pregnancies according to ESHRE guidelines
• History of implantation failure, considered as the lack of pregnancy after the transfer of 2 good-quality (grade A or B for inner mass cell and trophectoderm (29)) euploid embryos
• History or suspicion of Asherman syndrome
• Autoimmune disease
• Couple first degree consanguineous