BMI Effect on the Response to Ovulation Induction in Letrozole vs Clomid

There is an increased prevalence of high Body mass index (BMI) all over the world.High BMI is shown to have an impact on the female reproductive system.It can contribute to both ovulatory and anovulatory subfertility. Clomiphene citrate and Letrozole have been used for treatment of infertility.Both are used for induction of ovulation. Clomiphene citrate is an estrogen receptor antagonist .It increases serum FSH and it has its limitation due to his antiestrogenic effect,it has an ovulation rate 70-80% but pregnancy rate is only 22% because of its anti-estrogenic effect on endometrium and poor cervical mucus (Legro RS et al.,2007) Letrozole is an aromatase inhibitor which inhibits the production of estrogen, which influences the action of the brain's hypothalamus and pituitary on the functioning of the ovaries by increasing FSH.Due to the antiestrogenic effect of clomiphene citrate,Letrozole can be used as an alternative. The investigators are comparing the effect of both medications on the outcome of the induction of ovulation in women with high BMI.