From the Guidelines
Letrozole is recommended for ovulation induction in fertility treatment at a dose of 2.5 to 5 mg daily for 5 days, starting on day 3-5 of the menstrual cycle, as it has been shown to be effective and safe, with fewer side effects than clomiphene citrate, as supported by recent studies 1. The most common starting dose is 2.5 mg, which can be increased up to 7.5 mg in subsequent cycles if ovulation doesn't occur.
- Letrozole works by temporarily reducing estrogen levels, which triggers the pituitary gland to increase follicle-stimulating hormone (FSH) production, stimulating ovarian follicle development.
- This medication is particularly effective for women with polycystic ovary syndrome (PCOS) and has fewer side effects than clomiphene citrate, including a lower risk of multiple pregnancies.
- Common side effects include hot flashes, headaches, and fatigue.
- Patients should be aware that Letrozole is used off-label for fertility treatment in many countries, though it has become a first-line treatment option due to its effectiveness and safety profile, as noted in recent guidelines 1.
- Follicle development should be monitored with ultrasound, and ovulation typically occurs 5-12 days after the last dose.
- The use of letrozole does not reduce the number of mature oocytes obtained or their fertilisation capacity, and no effect on congenital abnormality rates in children has been observed, as reported in a recent study 1.
From the Research
Dosage and Usage of Letrozole for Ovulation Induction and Fertility Treatment
- The recommended dosage of Letrozole for ovulation induction is 2.5 mg per day, taken on days 3-7 of the menstrual cycle 2, 3.
- Letrozole has been shown to be effective in inducing ovulation in women with anovulatory polycystic ovary syndrome (PCOS) and ovulatory infertility 2.
- The use of Letrozole for ovulation induction has been compared to Clomiphene citrate, with Letrozole showing similar or superior pregnancy rates 2, 3, 4.
- Letrozole has a shorter half-life and fewer side effects compared to Clomiphene citrate, and does not appear to affect the receptivity of the endometrium 4.
Efficacy of Letrozole for Fertility Treatment
- Letrozole has been shown to be effective in treating women with chronic anovulation, unexplained infertility, and diminished ovarian reserve 4.
- The pregnancy rates achieved with Letrozole are equal or superior to those achieved with Clomiphene citrate, using bio-equivalent doses 4.
- Letrozole may be a useful adjunct to gonadotropin treatment for women who have been unsuccessful in achieving pregnancy with Clomiphene citrate 4.
Safety and Tolerability of Letrozole
- Letrozole is generally well-tolerated, with the most common side effects being hot flushes, nausea, and fatigue 5, 6.
- Letrozole has a favorable safety profile compared to Clomiphene citrate, with fewer side effects and a shorter half-life 4.
- The long-term effects of Letrozole on bone mineral density and lipid profile have not been determined, and may require monitoring 6.