Optimal Length of Progesterone Supplementation Before the Transfer of Cryopreserved (Frozen)-Thawed Day 3 Embryos in an Artificial Cycle With Exogenous Estrogen and Progesterone

"Procedures Transvaginal ultrasound (US) and hormone analysis for FSH, LH, E2 and P on day 2 of the cycle will be performed. The artificial preparation of the endometrium consists of 7 days oestradiol valerate (Progynova®, Bayer-Schering Pharma AG, Berlin, Germany) 2 mg bid (bi-daily), followed by 6 days oestradiol valerate 2 mg tid (thrice daily). On day 13, the endometrium is measured. If endometrial thickness is more than 7 mm, patients are randomly assigned to group A or B. All patients with an endometrium less than 7 mm on day 13 of estrogen stimulation, are excluded.~Group A receives 5 days of micronized progesterone vaginally (Utrogestan® ((Utrogestan, Besins International), 3x200mg daily), group B receives 3 days of micronized progesterone vaginally. On the 5th (group A) or 3rd (group B) day of progesterone supplementation, the cryopreserved-thawed day 3 embryo is transferred."