Letrozole Versus Clomifene Citrate for Ovulation Induction

Double Blind Cross-over Randomized Controlled Trial Comparing Letrozole Versus Clomifene Citrate for Ovulation Induction in Women With Polycystic Ovarian Syndrome

The primary aim of the study is to assess the efficacy of letrozole as an ovulation induction agent and to test the hypothesis that letrozole will generate better pregnancy rates with fewer multiple pregnancies and higher live birth rate than the current standard agent, clomifene citrate in anovular infertile women with polycystic ovarian syndrome.

Inclusion Criteria:

1. Age: 18 - 39

2. BMI < 36

3. Infertility due to anovulation

4. PCOS: At least two of the following diagnostic criteria of:

   1. Oligo/amenorrhoea
   2. Hyperandrogenaemia: biochemical (testosterone ≥2.5 nmol/l or free androgen index (FAI) ≥ 5) or clinical (acne/hirsutism) evidence
   3. USS evidence of PCO (either ≥12 follicles measuring 2-9 mm in diameter, or an ovarian volume of > 10 ml)

5. No recent (within 6 months) treatment for induction of ovulation

6. Normal semen analysis (WHO 1999)

7. Proven patency of at least one Fallopian tube

Exclusion Criteria:

1. Inability to give informed consent
2. Contraindication to letrozole or clomifene citrate
3. Absence of any inclusion criteria