Comparison of Live Birth Rate in Natural Cycle Single Euploid FET Versus Without Luteal Phase Support

Intermittent transvaginal ultrasound throughout the cycle to monitor follicular growth

Serial measurements of serum Luteinizing Hormone (LH), Estradiol (E2) and Progesterone (P4 )levels throughout the cycle to determine ovulation. LH-surge is identified when a rise of 180% above the previous level occurred and ovulation is confirmed with a decrease in E2 concentration, and a rise of progesterone level to ≥ 1.0 ng/ml (Irani et al., 2017).

On day of ET procedure, to administer 200 mg of vaginal progesterone and increase to 300 mg/day from the day after the ET onwards until the pregnancy test. In case of an implantation, vaginal P4 will be continued until 7 weeks of pregnancy

Serum P4 will be drawn before starting LPS in form of vaginal progesterone on the day of ET procedure

Serum P4 will be drawn when study group participants are admitted to the clinic for the ET procedure.

The procedure in which embryo is placed in the uterus.

Pregnancy will be confirmed / excluded by measurement of serum hCG 10 days after ET procedure and a level of \> 15 IU will be regarded as positive result. The definitions of biochemical, ectopic, clinical and ongoing pregnancy follow the ICMART criteria (Zegers-Hochschild, 2006)

Serum P4 will be drawn on day 5 or day 6 after the ET procedure and together with the hCG 10 days after ET procedure