To evaluate whether treatment with Estradiol supplementation during the luteal phase improves IVF outcomes

Patients undergoing IVF treatment with controlled ovarian hyperstimulation using a GnRH analog will receive 4 mg estradiol valerate in the luteal phase.Patient's followup will include E2 progesterone and BHCG 14 days after embryo transfer and vaginal ultrasound on day 21 and 28 after embryo transfer

The study will include Patients undergoing IVF treatment with controlled ovarian hyperstimulation using a daily GnRH analog in a long protocol,older then 18, .The women will be randomised to two groups.Both groups will be given vaginal tabs of natural micronized progesterone(Uterogestan)

The study group will be given oral estradiol Valerate 4 mg.Prior to treatment, each patient will be signed on informed concent.

Patients will be excluded if they are older than 40, have any systemic illnesses or a personal or family history of a thromboembolic event.

Follow up:

Verification of pregnancy status and hormonal profile will be carried out on day fourteen after embryo transfer by means of serum hCG,P and E2. clinical pregnancy will be defined as the presence of a gestational sac on ultrasonography on day 21 after embryo transfer and fetal heart will be evaluated on day 28

Inclusion Criteria:

• Women treated for infertility with controlled ovarian hyperstimulation using daily GnRH agonist

Exclusion Criteria:

• Women younger then 18 or older then 40
• Women with systemic disease
• Women with a family or personal history of thromboembolic event