All patients will undergo in vitro fertilization.

Serum 25 (OH) D samples will be collected within1 week before oocyte retrieval.

Whole blood specimens will be collected in serum separator tubes using acceptable medical techniques to avoid hemolysis.

Ultrasound guided fresh embryo transfer will be performed on day 5 after fertilization.

clinical pregnancy will be confirmed by observation of intrauterine sac visible on ultrasound performed 4-5 weeks after embryo transfer.

PATIENTS AND METHODS

Protocol Outline:

The Study:

Study site:

Ain Shams University Maternity Hospital.

Study Design:

A prospective Cohort study.

Study setting:

The study will be conducted at Ain Shams University Maternity Hospital.

Study population:

The study will include all women planned to undergo IVF due to unexplained infertility.

Methodology:

The study will be approved by the hospital ethics committee.

All included women will undergo the following:

• History taking.
• General and abdominal examination.
• Vaginal examination and assessment
• Pelvic ultrasound.
• Routine laboratory investigations including complete blood picture, hematocrit, liver and kidney function tests and coagulation profile.
• Preoperative senior anesthetist assessment.
• Hysteroscopy.

All patients will undergo IVF.

Serum 25(OH)D samples will be collected within1 week before oocyte retrieval.

Whole blood specimens will be collected in serum separator tubes using acceptable medical techniques to avoid hemolysis.

Ultrasound-guided fresh embryo transfer will be performed on day 5 after fertilization.

clinical pregnancy will be confirmed by observation of intrauterine sac visible on ultrasound performed 4-5 weeks after embryo transfer.

Measurement of Outcomes

1. serum 25 (OH) D levels.

2. Number of oocyte.

   Most studies put the optimal number of retrieved oocytes between 10 and 15.

3. The implantation rate:

   Calculated as the number of gestational sacs observed by ultrasound divided by the number of embryos transferred, multiplied by 100.

4. Number of gestational sac.

Inclusion Criteria:

• Age between 20 and 35 years old.
• Body mass index between 20 - 30.
• Unexplained infertility .
• Follicle-stimulating hormone level 12 IU/L or lower (baseline level, cycle day 3).
• Normal hysteroscopy ( healthy uterus with no fibroids or other growths)
• Fresh embryo transfer of 2 or more blastocysts stage.
• Embryo transfer on day 5 after fertilization

Exclusion Criteria:

• Women younger than 20 years old or older than 35 years old.
• Previous one or more failed IVF.
• Uncorrected congenital or acquired uterine anomalies.
• Other causes of infertility rather than unexplained infertility.
• Less than 2 embryo transfer, cleavage stager frozen embryo transfer.

• Age between 20 and 35 years old.
• Body mass index between 20 - 30.
• Unexplained infertility .
• Follicle-stimulating hormone level 12 IU/L or lower (baseline level, cycle day 3).
• Normal hysteroscopy .
• Fresh embryo transfer of 2 or more blastocysts stage.
• Embryo transfer on day 5 after fertilization