There has been a recent significant increase in the frozen embryo replacement (FER) cycles due to freeze-all cycles to decrease the risk of ovarian hyperstimulation syndrome. Now a days making frozen embryo transfers (FETs) a viable alternative to fresh embryo transfer

There has been a recent significant increase in the frozen embryo replacement (FER) cycles due to freeze-all cycles to decrease the risk of ovarian hyperstimulation syndrome. Now a days making frozen embryo transfers (FETs) a viable alternative to fresh embryo transfer, with reports from observational studies and randomized controlled trials suggesting that:

1. The endometrium in stimulated cycles is not optimal for implantation
2. Pregnancy rates are increased following FET
3. Perinatal outcomes are less affected after FET
4. Preimplantation genetic screening We will follow only natural and modified natural cycles patients. Spontaneous ovulation will documented with hormonal and sonographic monitoring. Hormonal monitoring are including estradiol and luteinizing hormone (LH). Sonographic monitoring is including follicule diameter (16-20 mm). At modified natural cycles we will use hCG triggering for ovulation approximately 16-20 mm diameter.

We will compare success rate between natural and modified natural cycles

Inclusion Criteria:

• Patient who are admitted to the IVF center and who will be transferred to frozen embryos.
• Infertile women under 40 years of age who accepted this study.
• Unexplained infertilite couple.
• All ovulatory patient.
• Male factor.
• Tubal factor.

Exclusion Criteria:

• Patients who made intrauterin surgery.
• Over 40 years of age women.
• Patients with preimplantation genetic diagnosis.
• Anovulatory patient.

woman who is infertile at reproductive age

This study will bw carried out as a prospective randomized clinical trial on regular menstruating patients arriving for transfer of frozen embryo to the center in a single IVF center. Results will collected and recorded daily during the study. With 80% power analysis minimum number of patients 0.05% significance level is 240.

Study will be designed in 1 year.

We did not decide for this but if they need any information we can support all