Natural Cycle Protocol

Ultrasound monitoring to monitor follicular and endometrial growth. Serial measurements of serum Lutenizing Hormone (LH), estradiol (E2), and progesterone (P4) to identify ovulation.~Minimal endometrial thickness of 7 mm is required. No progesterone supplementation. Embryo transfer (ET) will be scheduled 5 days after the day of ovulation (120 hours of P4 exposure).~Blood samples will be drawn to measure PIBF, IL-17, IFγ, IL-10, IL-4 and TGF-ß1 on day of ovulation (P4 rise), on the day before ET, on the day of ET and 3 and 10 days later, between 9 and 12 am.~A blood test to measure beta human chorionic gonadotropin (ß-hCG) will be performed 3 and 10 days after ET and at 5 weeks +/- 3 days in case of pregnancy, between 9 and 12 am.~In case of pregnancy, a blood test to measure PIBF, IL-17, IFγ, IL-10, IL-4 and TGF-ß1 will be performed at 5 weeks +/- 3 days between 9 and 12 am..

Hormone Replacement Therapy Protocol

Ultrasound monitoring of endometrial growth and exclude growing follicle~Oral Estradiol Valerate (Progyluton) 4 mg on cycle day 2 at 7 pm for 2 days. On 3rd day, increase dose to 6 mg. The dose may be increased based on endometrial thickness.~Once endometrial thickness is at least 7 mm and trilaminar, after 10-15 days of Estradiol Valerate administration, start Endometrin 100 mg at 1 pm and 9 pm. From 2nd day onwards increase to 3 times daily. Continue Progyluton \& Endometrin until 12 weeks of pregnancy~ET on the 5th full day of Endometrin administration~Blood test to measure PIBF, IL-17, IFγ, IL-4, IL-10 and TGF-ß1 on the 1st day of Endometrin supplementation (before 1st administration), on the 4th day of Endometrin administration, on the day of ET and 3 and10 days after, 4 to 7 hours after the morning administration.~Blood test to measure beta human chorionic gonadotropin (ß-hCG) will be performed 3 and 10 days after ET and at 5 weeks +/- 3 days if pregnancy.