A. Who are candidates for Letrozole?
1. Letrozole is an oral fertility enhancing medication for patients with ovulatory problems (such as failure to ovulate or inconsistent ovulation). Some patients with ovulation difficulty have other medical conditions that require specific therapy (such a Synthroid for hypothyroidism). Letrozole is offered to patients who have no known medical condition hindering ovulation and to patients whose medical treatment by itself fails to stimulate ovulation. Some terms for ovulation dysfunction are: PCOS (polycystic ovary syndrome), anovulation, irregular ovulation, luteal phase deficiency, and progesterone deficiency.
B. Evaluation
1. History and physical in the office 2. Semen analysis 3. Progestin challenge (for those who are not having any periods): A progesterone-type hormone is prescribed to attempt to induce a period. Call us if you do not have a period beginning 2-7 days after you finish the prescription. 4. Basic Blood work (done in the morning while fasting). This is done to evaluate you for medical conditions which could impair ovulation. a. Thyroid stimulating hormone (TSH) b. Prolactin c. Glucose, Insulin, or HgbA1C d. AMH 5. Optional additional blood work: a. Insulin and/or glucose challenge test b. Testosterone, DHEAS, and 17-OH progesterone levels (these currently are recommended only for women with evidence of masculinization)
C. How Letrozole is prescribed
1. The FIRST day of each period (either spontaneous or induced by a progestin challenge) is called day ONE. 2. Letrozole is taken every day from days 3-7.The dose of Letrozole is 2.5 mg (one pill a day). 3. Ovulation should occur between days 14-19 (so please have intercourse beginning around day 12 and don’t skip two days in a row through at least day 20). 4. In the first cycle of Letrozole, you should have a blood progesterone level drawn 5-7 days after ovulation. Use a BBT graph or ovulation test kit to improve the accuracy of your ovulation estimate. 5. If you get an excellent response from Letrozole (ovulation AND excellent progesterone level) we’ll continue Letrozole for 3-4 cycles. 6. However, we know that not everyone will be successful with Letrozole. Examples of problems with Letrozole response: a. failure to ovulate b. ovulation but inadequate luteal phase progesterone c. excellent apparent response to Letrozole, but failure to conceive after 3-4 cycles For any of the above examples, you’ll need to schedule an appointment so we can discuss further options (adding empiric insulin sensitizing meds, referral to a reproductive endocrine practice) 7. If you develop pain, you’ll need to come into the office for an examination. 8. Side effects of Letrozole are usually temporary but can include hot flashes, breast discomfort, nausea, vomiting, headache, or visual disturbances. The risk of twins is 3-4% when you conceive on Letrozole.
