Comparison of the success rate of letrozole and clomiphene citrate in women undergoing intrauterine insemination

Journal of Research in Medical Sciences 11/2006; 11(6).
Source: DOAJ


BACKGROUND: This study was conducted to compare the success rate of daily administration of aromatase inhibitor letrozole at a dose of 5 mg when administrating clomiphene citrate (CC) 100 mg daily in women undergoing superovulation and IUI.
METHODS: This prospective randomized trial was done in Research and Clinical Center for Infertility (Shahid Sadoughi University), Yazd, Iran. Ninety-five patients with unexplained and mild male factor infertility were studied. Using a computer-generated random table, the patients were randomized into two groups, which were treated with 5 mg of letrozole daily (42 patients, 42 cycles) or 100 mg of CC daily (53 patients, 53 cycles). The data were analyzed using Student's t-test and chi square test.
RESULTS: The mean age and duration of infertility in both groups were similar. There was a significant difference between the two groups in the total numbers of follicles during stimulation (5.45 ± 4.2 in CC group vs. 3.07 ± 2.1 in letrozole group) (P = 0.01). No significant difference in the endometrial thickness was found between the two groups (letrozole group = 6.9 ± 2.2, CC group = 7.8 ± 1.8). The mean levels of LH and FSH in both groups were similar. P value of difference in hormone levels between two groups were 0.33 and 0.47, respectively, but there was a significant difference in mean E2 levels between the two groups (241.28 ± 167.537 in letrozole group vs. 867.34 ± 296.689 in CC group) (P = 0.018). The mean number of gonadotropin ampules used in both groups was the same. Pregnancy rate per cycle was 9.5% in the letrozole group and 5.7% in the CC group (P = 0.6). Two out of the three pregnancies in the CC group (66.6%) and one out of the four pregnancies in the letrozole group resulted in a miscarriage (25%). One twin pregnancy (33%) occurred in the letrozole group and none in the CC group. Ovarian hyperstimulation syndrome (OHSS) did not occur in either of the two groups.
CONCLUSIONS: In IUI, superovulation with clomiphene citrate and letrozole was associated with similar pregnancy rates, but the miscarriage rate was higher with clomiphene citrate.
KEY WORDS: IUI, letrozole, clomiphene citrate, superovulation.

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    • "mm vs. 8.1±1.9 mm; p=0.0001) that is similar to results of Barroso et al (2006) (11). However, in the studies performed by Al-Fozan et al (2004), Jee et al (2006), and Davar et al (2006) they did not find any significant relationship between these two groups (12,13,16,18). "
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    ABSTRACT: Background: Clomiphene citrate (CC) an agonist and antagonist of estrogen, is the first line treatment in ovarian stimulation. Anti-estrogenic effect of CC in endometrial thickness and cervical mucus has negative effect on pregnancy rate. Letrozole is an Aromatase Inhibitor has been seen that has acceptable pregnancy rate compared to CC. Objective: The aim of this study was to compare the efficacy of letrozole and clomiphene citrate (CC) with gonadotropins for ovarian stimulation in women candidate for intrauterine insemination (IUI). Materials and Methods: One hundred sixty patients eligible to IUI therapy enrolled in this study. Patients randomized to two groups: group A (received letrozole-gonadotropin) and group B (received CC-gonadotropin). In group A (n=80) letrozole was given on days 3-7 of the menstrual cycles. In group B clomiphen citrate was given like letrozole combined with human menopausal gonadotropin (hMG) administered every day starting on day 8. Ovulation was triggered with urinary HCG when the leading follicle (s) reached 18 mm in diameter. A single IUI was performed 36-40 hours later. The ovarian stimulation response (E2 levels and number of follicles, clinical pregnancy and endometrial thickness) was primary outcome. Results: Both groups were similar in demographic characteristics. There was a significantly lower peak serum E2 level in the letrozole group compared with CC. (236±86 Vs. 283±106 pg/mL, respectively; p<0.002). The number of mature (>18 mm) preovulatory follicles was significantly higher in CC group than letrozole group (2.2±.68 Vs. 2.02±0.63 respectively; p=0.025). Endometrial thickness measured at the time of hCG administration was significantly higher in letrozole group. (9.08±1.2 mm Vs. 8.1±1.9 mm; p=0.0001). The clinical pregnancy rate was comparable between two groups. Conclusion : Letrozole is a good and cost-effective alternative to CC in IUI cycles.
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