Letrozole is a drug used to stimulate or regulate ovulation (ovulation induction) and can be used as an alternative to Clomifene. Letrozole is an aromatase inhibitor and works by lowering the production of oestrogen.
When Letrozole May Be Recommended
- If you have previously used Clomifene for ovulation induction but not responded.
- If you have persistently over‑responded (too many follicles) to Clomifene.
- If you have experienced unwanted side effects from Clomifene.
- If your womb lining (endometrium) did not thicken sufficiently during Clomifene treatment.
How to Take Letrozole
The first day of bleeding is considered Day 1 of your cycle. Letrozole should be taken from Day 2 to Day 6 (for 5 days). An ultrasound scan will usually be carried out around Day 10 to Day 12 to monitor your response.
If you don’t have periods (or if they are very infrequent ) you may also be prescribed a tablet called Medroxyprogesterone (Provera).
You are advised to take a home pregnancy test before taking Provera tablets.
Provera 10mg should be taken for 7 consecutive days. You should then have a ‘withdrawl bleed’. It can take up to 10 days for this bleed to start after the last Provera tablet is taken. If you do not have this bleed more than 10 days after taking the last table, please call the Fertility Nurse Specialist of advice.
If you start to bleed naturally while you are still taking the Provera, please stop taking these and start Letrazole as directed on day 2 of bleeding instead.
Effectiveness
Studies show that Letrozole can improve successful ovulation rates and does not adversely affect the endometrial lining. It is also associated with lower multiple pregnancy rates compared to Clomifene.
Side Effects
The most common side effect is hot flushes. Less common side effects include fatigue, dizziness, nausea, headaches, bloating, muscle aches and blurred vision.
Stop taking the medication and contact the clinic immediately if you experience any eyesight changes.
Monitoring During Treatment
On Day 1 of the cycle in which you start Letrozole, please contact the clinic to arrange an ovarian ultrasound scan (usually carried out only during the first cycle). This helps determine the timing of ovulation and checks for overstimulation.
If overstimulation is detected, the cycle will be cancelled and you will be asked to avoid intercourse until your next cycle to reduce the risk of multiple pregnancy.
Scans take place between 8am and 9am, usually on Day 10 or Day 12. A blood test will also be taken around a week later to confirm ovulation. Treatment may continue for up to six months, and your dose may be adjusted depending on your response.
If You Become Pregnant
If you have a positive pregnancy test, please contact the Fertility Nurse Specialist on 01324 567166. An early pregnancy scan will be arranged at around 7 weeks.
Arrange Your Ultrasound Tracking Scan
Contact the Fertility Nurse Specialist
Forth Valley Royal Hospital
Fertility Clinic Direct Line: 01324 567166
Please remember that it is your responsibility to keep in touch with the Fertility Nurse Specialist so that your treatment can be monitored and appropriate follow‑up arranged.