Introduction: Letrozole, is a third generation non-steroidal selective reversible and highly potent aromatase inhibitors which was used in breast cancer is a new drug used for ovulation induction. The present study aims to assess safety and efficacy of the use of letrozole in the patient undergoing ovulation induction, to determine ovulation rate, to evaluate  the effect of letrozole on uterine endometrial thickness and to study the final success rate of treatment in terms of pregnancy rate

Material and Methods: A total 60 patients attending with primary and secondary infertility were included in the study. All women were given tablet letrozole 5mg daily from day 2 of the mensis for 5 day. Patients were followed up for maximum up to three cycles.

Results: 60 women of the reproductive age group were studied. Mean age of the women was.27±3.47 years. 52 Women (86.66%) had primary infertility and eight women (13.33%) had secondary infertility. Mean number of follicles in first cycle was 1.47±0.66, mean number of follicles in second cycle was1.70±0.66, mean number of follicles in the third cycle was 1.62±0.66. Average number of dominant follicle was 1.58 ± 0.66. Out of 155 cycle total number of pregnancies was 10, pregnancy rate per cycle was(10/155) 6.45 % , pregnancy rate per ovulatory cycle was (10/129) 7.75% and cumulative pregnancy rate was(10/60) 16.66%.

Conclusions: Letrozole can be used as effective ovulation inducing agent, with no case of multiple pregnancy in the present study. However long-term multicenter randomized case controlled trials are needed with large sample size to conclude about the efficacy and safety of the drug, especially to study long term effect in fetal life, infancy and beyond.

Keywords: Letrozole, Primary infertility, Secondary infertility, Ovulatory cycles, Ovulation induction, Cumulative pregnancy rate.

1. Speroff L, Fritz MA. Female Infertility In: Clinical Gynecologic Endocrinology and infertility. Eds: speroff L, Fritz MA, Lippincott William and Wilkins, Philadelphia pp1013-67.
2. Jacky Boivin, LauraBunting, John A Collins International estimates of infertility prevalence & treatment seeking: potential need and demand for infertility medical care. Human Reproduction pp1-7, 2007.
3. Kurl RN, Morris Id. Differential depletion of cytoplasmic high affinity oestrogen receptors after the in vivo administration of the antioestrogens, clomiphene, MER-25 and tamoxifen. BR J Pharmacol 1978;62:487-493.
4. Robert f.Casper and Mohamed F.M. Mitwally REVIEW: Aromatase inhibitors for ovulation induction the Journal of Clinical Endocrinology & Metabolism 91(3): 760-771.
5. Greenblatt RB, barfield We, Jugack EC Ray AW, Induction of ovulation with MRL/41, preliminary report, JAMA 178:255, 1961.
6. Mitwally MFM, Casper rf. Aromatase inhibition: a novel method of ovulation induction in women with polycystic ovarian syndrome. ReprodTechnol 2000;10:244-247.
7. BraniganEf, Estes MA: A randomised clinical trial of treatment of clomiphene citrate resistant anovulation with the use of oral contraceptives ovarian suppression and repeated clomiphene citrate treatment. Am journal of obstet Gynecol.
8. Nestler Je, Jakubowicz DJ, Evans Ws, pasquali R effects of metformin on spontaneous and clomiphene induced ovulation in polyssystic ovarian syndrome. New England Jmed 338:1876,1998.
9. Z.Diamant, S.evron induction of ovulation by combined clomiphene citrate and dexamethasone in clomiphene nonrespondereuropean Journal of OBST& GYN vol.11, issue 5. Page 335:340.
10. Keay SD, Jenkins JM Adjuvant use of dexamethasone in clomid resistant patients Fertilsteril 80:230,2003.
11. Danoforthdr=R: Endocrine and paracrine control of oocyte develop[ment Am J ObstetGynecol172:747,1995.
12. Thompson Cr, Hansen LM pergonal (menotropins) a summary of clinical experience in induction of ovulation and pregnancy FertilSteril 21:844,1970.
13. Vendola KA, Zhou J, Adesanya OO, Weil Sj, bondy CA: Androgens stimulate early stages of follicular growth in the primate ovary. J Clin Invest 1998;101:2622-2629.
14. Sh Tehrani Nrjad E, Abediasl Z, Rashidi BH, AzimiNekoo E, Shariat M, Amirchaghmaghi E Comparison of the efficacy of the aromatase inhibitor letrozole and clomiphene citrate gonadotropins in controlled ovarian hyperstimulation : a prospective, simply randomized, clinical trial. JassistRepord GENET. 2008 Apr 19.
15. Begum MR, Quadir E, Begum A, Begum RA, Begum M. Role of aromatase inhibitor in ovulation induction in patients with poor response to clomiphene citrate J obstetGynecol Res.2006 oct;32(5):502-6.
16. Al Fadhli R; Sylvestre C; Buckett W; Tan SL; Tulandi T A randomized trial of superovulation with two different doses of letrozole fertile steril 2006 85(1):161-4(issn 1556-5653).
17. Badway A, Mosbah A, Tharwat A, Eid M Extended letrozole therapy for ovulation induction in clomiphene resistant women with polycystic ovarian syndrome: a novel protocol fertile steril 2008 Aug 13.
18. Mitwally MF, Bijian MM, Casper RF pregnancy outcome after the use of an aromatase inhibitor for ovarian stimulation Am J obstetGYnecol 2005; 192:381-6.

Dr Vijay Singh Nahata

Assistant Professor, Mahatma Gandhi Medical College, Jaipur, Rajasthan, India