Letrozole versus Clomiphene for Infertility in the Polycystic Ovary Syndrome

Abstract

BACKGROUND Clomiphene is the current first-line infertility treatment in women with the polycystic ovary syndrome, but aromatase inhibitors, including letrozole, might result in better pregnancy outcomes. METHODS In this double-blind, multicenter trial, we randomly assigned 750 women, in a 1:1 ratio, to receive letrozole or clomiphene for up to five treatment cycles, with visits to determine ovulation and pregnancy, followed by tracking of pregnancies. The polycystic ovary syndrome was defined according to modified Rotterdam criteria (anovulation with either hyperandrogenism or polycystic ovaries). Participants were 18 to 40 years of age, had at least one patent fallopian tube and a normal uterine cavity, and had a male partner with a sperm concentration of at least 14 million per milliliter; the women and their partners agreed to have regular intercourse with the intent of conception during the study. The primary outcome was live birth during the treatment period. RESULTS Women who received letrozole had more cumulative live births than those who received clomiphene (103 of 374 [27.5%] vs. 72 of 376 [19.1%], P = 0.007; rate ratio for live birth, 1.44; 95% confidence interval, 1.10 to 1.87) without significant differences in overall congenital anomalies, though there were four major congenital anomalies in the letrozole group versus one in the clomiphene group (P = 0.65). The cumulative ovulation rate was higher with letrozole than with clomiphene (834 of 1352 treatment cycles [61.7%] vs. 688 of 1425 treatment cycles [48.3%], P<0.001). There were no significant between-group differences in pregnancy loss (49 of 154 pregnancies in the letrozole group [31.8%] and 30 of 103 pregnancies in the clomiphene group [29.1%]) or twin pregnancy (3.4% and 7.4%, respectively). Clomiphene was associated with a higher incidence of hot flushes, and letrozole was associated with higher incidences of fatigue and dizziness. Rates of other adverse events were similar in the two treatment groups. CONCLUSIONS As compared with clomiphene, letrozole was associated with higher live-birth and ovulation rates among infertile women with the polycystic ovary syndrome. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others; ClinicalTrials.gov number, NCT00719186.)

Effect of pretreatment with oral contraceptives and progestins on IVF outcomes in women with polycystic ovary syndrome

“…Nonetheless, our results need to be confirmed by randomized controlled trial. Second, the mean BMI of the studied population was relatively normal, which was lower than that in some other ethnic PCOS populations (Legro et al, 2014b), such that there may have been relatively increased serum levels of synthetic hormones (Edelman et al, 2009). However, a recent Cochrane meta-analysis did not find increasing BMI that impacted the effectiveness of hormonal contraceptives (Lopez et al, 2016).…”

Aromatase Imaging with [N-Methyl-11C]Vorozole PET in Healthy Men and Women

“…11 C-vorozole PET is useful in measuring aromatase expression in the human body, supporting future investigation as a tool for diagnosis, treatment monitoring, and treatment optimization, as well as pharmacokinetic and pharmacodynamic assessment of new aromatase inhibitors in development for cancer and other disorders (35) in which aromatase inhibition is indicated.…”

Hormonal Changes After Laparoscopic Ovarian Diathermy in Patients with Polycystic Ovarian Syndrome

“…Letrozole had higher live birth/ovulation rates without significant differences in overall congenital anomalies [7].…”