Cohort Study Investigating the Association Between Antichlamydial Antibody Positivity and ART Outcomes in Women With TFI

At the first day of stimulation blood analyses for immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) to major chlamydial antigens (anti-C.trachomatis), major outer membrane protein (MOMP) and plasmid-encoded protein (pgp3) will be performed for patients found eligible for the study. According to the result of chlamydial antibody test (CAT) participants will be divided into two groups: group A - women with at least one of antibodies detected (CAT+); Group B - seronegative subjects (CAT-). Women of both groups will undergo a conventional ovarian stimulation (COS) with GnRH antagonist and daily gonadotropin administration at the dose of 150-300 international unit (IU). Retrieved oocytes following fertilization (conventional IVF or ICSI) will be cultured to Day 3-5 in vitro; ultrasound guided single or double embryo transfer will be performed; remaining embryos of eligible quality will be vitrified. Patients will be followed up to live birth. Frozen/thawed embryo transfers (FET) will be performed until at least one live birth (≥20 weeks of gestation) occurred or all embryos resulting from the mentioned assisted ovarian stimulation were used.