Palihawadana TS, Wijesinghe PS, Seneviratne HR. Factors associated with nonresponse to ovulation induction using letrozole among women with World Health Organization group II anovulation.
J Hum Reprod Sci 2015;
8:75-9. [PMID:
26157297 PMCID:
PMC4477453 DOI:
10.4103/0974-1208.158598]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/15/2015] [Accepted: 04/16/2015] [Indexed: 11/04/2022] Open
Abstract
CONTEXT:
Letrozole, a third generation aromatase inhibitor is gaining importance in ovulation induction. Some prefer to use it as a second line agent in women who fail to respond to clomifene citrate. However, our knowledge about the predictors of response to letrozole is limited.
AIMS:
The study was aimed at identifying the factors associated with letrozole resistance among women with World Health Organization (WHO) group II anovulation.
SUBJECTS AND METHODS:
Study was conducted at the infertility clinic at a tertiary care hospital in Sri Lanka. A case–control study design was used and included 50 subjects with WHO group II anovulation (25 clomifene responsive and 25 clomifene resistant). After a treatment cycle of letrozole, the factors were compared between the subjects who responded and those who failed to respond to treatment.
RESULTS:
Ovulation was achieved in 76% (n = 19) of subjects who had responded to clomifene previously and in 24% (n = 6) with clomifene resistance. The factors associated with letrozole resistance included the presence of hirsutism (odds ratio [OR]: 3.89; 95% confidence interval [CI]: 1.2–12.3) and clomifene resistance (OR: 10.03; 95% CI: 2.81–35.7). The early follicular phase mean (standard deviation) luteinizing hormone level was significantly higher among the nonresponders (9.75 [4.78] – 7.28 [2.3]; P = 0.02). Nonresponders showed significantly lower levels of oestradiol on the 5th and 9th days (28.50 [3.39] pg/mL vs. 7.49 [3.62] pg/mL; P = 0.0007 and 142.04 [76.22] pg/mL vs. 28.10 [12.8] pg/mL; P = 0.0001) of the menstrual cycle, respectively.
CONCLUSIONS:
The features associated with resistance to Letrozole at a dose of 2.5 mg show some overlap with those associated with clomifene resistance. However, some features do not show similar association. The effectiveness of letrozole at a dose of 2.5 mg in induction of ovulation among women with clomifene resistance is low and it does not seem to be a suitable treatment at a dose of 2.5 mg for this indication.
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