A comparison of the efficacy of two doses of letrozole alone or with continuous recombinant follicle-stimulating hormone for ovulation induction in anovulatory women

Luteal phase support with oral progesterone improves live birth rate in intrauterine insemination cycles using letrozole

RESEARCH QUESTION

Does luteal phase support (LPS) with oral progesterone improve the live birth rate (LBR) in patients undergoing intrauterine insemination (IUI) cycles with letrozole?

DESIGN

This retrospective cohort study included 1199 IUI cycles with letrozole between January 2017 and December 2021. A nearest neighbour random matching approach was employed to pair the LPS group and the control group in a 1:2 ratio. Eight variables were chosen for matching in the propensity score matching (PSM) model: age; body mass index; duration of infertility; cause(s) of infertility; antral follicle count; basal concentration of FSH; rank of IUI attempts; and leading follicle size. LBR was selected as the primary outcome.

RESULTS

In total, 427 LPS cycles were matched with 772 non-LPS (control) cycles after PSM. The LBR was significantly higher in the LPS group compared with the control group (19.7% versus 14.5%; P = 0.0255). The clinical pregnancy rate (23.2% versus 17.6%; P = 0.0245) and ongoing pregnancy rate (20.6% versus 15.8%; P = 0.0437) were also significantly higher in the LPS group. The biochemical pregnancy rate, ectopic pregnancy rate and miscarriage rate were similar in the two groups (P > 0.05). The intergroup comparison revealed no significant variances in terms of gestational age, mode of delivery, ectopic pregnancy rate or abortion rate. Furthermore, there were no significant differences in birth weight or birth length between the two groups.

CONCLUSIONS

Luteal support with oral progesterone significantly improved the LBR in IUI cycles with letrozole, but did not affect neonatal outcomes.

Effectiveness of letrozole in pituitary downregulated normogonadotrophic young women with an initial poor response

It has been reported that 10 to 15% of young normogonadotrophic women show suboptimal response to standard long protocols. Letrozole (LE), an aromatase inhibitor, was shown to improve ovarian sensitivity to follicle stimulating hormone (FSH) and follicular response to gonadotrophin treatment in poor ovarian response patients. We reasoned that it might be possible to utilize LE in young normogonadotrophic patients with unexpected hypo-response in standard gonadotropin-releasing hormone agonist long protocol. A total of 652 patients defined as normogonadotrophic patients with unexpected hypo-response were divided into 2 groups, the +LE group and the +Gn group. +LE group: A fixed daily dose of 2.5 mg of LE was added on day 8 of stimulation. +Gn group: A fixed daily dose of 75 U of human menopausal gonadotrophin was added on day 8 of stimulation. The primary outcome measures were the number of oocytes obtained, fertilization rate, days of stimulation, and total FSH dosage. The secondary outcome measures were the implantation rate and ongoing pregnancy rate. There were no significant differences in the clinical and hormonal characteristics between the 2 groups. A shorter duration of stimulation and a lower dosage of recombinant FSH consumption on the day of human chorionic gonadotropin administration were all observed in the +LE group. Patients who received LE therapy showed a higher number of oocytes obtained and significantly higher fertilization rates. The implantation rate and ongoing pregnancy rate were comparable in both groups. LE significantly improves the number of oocytes obtained in patients with suboptimal response to standard gonadotropin-releasing hormone agonist long protocol.

A retrospective analysis of ovarian stimulation with letrozole in women undergoing artificial insemination by donor

The aim of this retrospective study was to determine the clinical pregnancy rate in women undergoing letrozole ovarian stimulation and artificial insemination by donor (AID). Between 2012 and 2015, 130 natural cycles, 939 letrozole cycles and 130 letrozole plus gonadotrophin cycles were conducted. Letrozole cycles were divided into three groups according to LH concentration on the day of HCG administration (LH <10 mIU/ml and follicle size ≥18 cm; LH ≤10 to <20 mIU/ml; and LH ≥20 mIU/ml). Pregnancy rates were 17.3%, 22.4% and 26.8%, respectively (P = 0.012). In women given 10 mIU/ml LH or more, logistic regression identified oestradiol (OR 1.002, 95% CI, 1.000 to 1.004, P = 0.029) and leading follicle size (OR 0.861, 95% CI, 0.772 to 0.960, P = 0.007) as significant predictive factors of pregnancy rate; the higher the oestradiol and the smaller the follicles, the better the pregnancy rate. The pregnancy rate was significantly higher in the letrozole plus gonadotrophin group than the letrozole group (P = 0.04). Better pregnancy rates can be achieved if LH surge occurs before HCG administration, especially with higher oestradiol and lower follicle size; treatment with letrozole plus gonadotrophin was significantly more effective than letrozole alone in AID.

Randomized controlled trial comparing letrozole with laparoscopic ovarian drilling in women with clomiphene citrate-resistant polycystic ovary syndrome

The aim of the present study was to compare the reproductive outcomes of letrozole and laparoscopic ovarian drilling (LOD) in women with clomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS). A total of 141 women with CC-resistant PCOS were enrolled and randomly allocated into groups A and B. Group A (n=71) received 2.5 mg letrozole from days 5 to 10 of menses for up to six cycles, and group B (n=70) underwent LOD. A 6-month follow-up was performed. No statistically significant difference was found in the baseline clinical characteristics and the major serum hormone profiles, including luteinizing hormone, follicle-stimulating hormone, estradiol and free testosterone, between the two groups. Women receiving letrozole had a lower rate of spontaneous abortion (6.9 vs. 15.8%) and higher clinical pregnancy (40.8 vs. 27.1%) and live birth (38.0 vs. 22.9%) rates; however, the differences were not statistically significant. Letrozole had superior reproductive outcomes compared with LOD in women with CC-resistant PCOS; therefore, letrozole could be used as the first-line treatment for women with CC-resistant PCOS.