Cases will be divided into two groups based on treatment they are prescribed by their consultant. Group A (n= 95)will consist of patients who will receive treatment cycles with 50mg Clomiphene citrate from day 2 to day 6 of menstrual cycle. Group B (n= 95) will consist of patients who will receive treatment cycles with Letrozole 2.5mg from day 2 to day 6 of menstraul cycle. 

In both the groups endometrial and follicular vascularity will be assessed by transvaginal doppler ultrasound on the 11th day of menstrual cycle. The dominant or largest follicle, together with all follicles>18mm in diameter will be graded using power doppler. 

This grading system will be based on the percentage of perifollicular circumference that will depict an echo signal and will range from grades:

1. grade 0- no detectable blood flow

2. grade 1- visible blood flow in 1-25% of follicular circumference

3. grade 2- blood flow in 26-50% of follicular circumference 

4. grade 3- blood flow in 51-75% of follicullar circumference 

5. grade 4- blood flow in 76-100% of follicular circumference 

Endometrial vascularity will be graded as-

Type A- Homogenous pattern, defined as a single hyperechoic, hypoechoic or isoechoic layer with absent or poorly defined central echogenic line

Type B- Triple line pattern, defined as multi-layered endometrium consisting of a prominent outer and inner hyper-echoic line and inner hypoechoic regions

All data will be recorded in an Excel sheet.

Using Mann-Whitney U test, statistical analysis will be done to compare the perifollicular and endometrial vascularity between the two treatment groups.