There are many protocols for prevention of ovarian hyperstimulation syndrome, intravenous calcium is a novel protocol. But still there is lack of evidence of it is real effect in prevention of OHSS & the mechanism of its action is still questionable . In the study the investigators try to search for the evidence for its effect & the real mechanism for its action.

The study population will be divided into 2groups each containing 100 infertile couples candidate for ICSI.

Group (A)active group: administration of 10% Intravenous calcium gluconate 10 ml in 200 mL of physiologic saline on the day of ovum pickup, day 1,day 2, and day 3 after ovum pickup. Intravenous infusion was performed within 30 minutes.

Group (B): placebo group: administration of 200 mL of 0.9% saline on the day of ovum pickup, day 1,day 2, and day 3 after ovum pickup. Intravenous infusion was performed within 30 minutes

Inclusion Criteria:

• infertile women aged 20 to 38 years.
• BMI ranged from 18 to 40.
• serum FSH within normal limits( 1-12IU /l)
• presented with ovarian response suggestive of being at risk of developing OHSS because of the presence of at least 15 follicles of 10 mm or greater on the day of hCG administration.

Exclusion Criteria:

• endocrinopathies.
• a systemic disease.
• using any medication (e.g., insulin-sensitizing drugs and GnRH antagonists.
• patients need coasting for high risk of OHSS.
• patients need cycle cancellation.
• severe male infertility requiring testicular sperm extraction.