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Letrozole

What is Letrozole?

Letrozole is an oral medication, which induces ovulation by blocking the conversion of testosterone into estrogen. This will, in effect, increase the brain production of FSH and LH and send a message to the ovary to increase the growth of the follicles (eggs).

Letrozole is a medication we often use to increase the ovulation rate or improve ovulation in women who are already ovulating. Letrozole was found to be superior to Clomid when inducting ovulation in patients with polycystic ovarian syndrome. Unlike Clomid, Letrozole does not come with the side effects of thinning the uterine lining or decreasing the cervical mucous.

Letrozole with Injections

The multiple pregnancy rate of Letrozole is not well studied, but it is thought to be similar to Clomid’s rate of 5-10%.

In patients who have previously used several cycles of clomid or Letrozole or have a history of low ovarian reserve,  may elect to use Letrozole in combination with gonadotropins injections. The combination typically has a higher pregnancy rate (up to 35%) and the risk or twins is about 25%. When we use the combination of oral medications and injections, we find that we reduce the amount of injections needed while maintaining the higher pregnancy rate.

Why Choose Letrozole with Injections?

The injectable medications known as Gonal-F and Follistim are synthetic forms of follicle stimulating hormone. Menapur is a combination of follicle stimulating hormone and Luteinizing Hormone. The key benefit of these injections is they counteract the side effects of Letrozole while increasing the estrogen levels and the number of follicles growing.

How Does Letrozole with Injections Work?

Letrozole is initiated on day 3-7, and the injections are added on day 6. A pelvic ultrasound is typically done on day 10 to carefully monitor the size of the follicles. Once the follicles reach maturation, an injection of hCG is given to induce ovulation. We can also combine letrozole with gonadotropins and an intrauterine insemination, which is typically done 24-36 hours after the hCG injection.

Letrozole Side Effects

· Abdominal bloating
· Pain in your side
· Nausea
· Dizziness
· Fatigue
· Headaches

What are the Side Effects of Letrozole with Injections?

Injectable Medication Side Effects:

These injectable medications are potent drugs with potential side effects: You may experience:

·  Headaches
·  Irritability
·  Depression
·  Fatigue

Ovarian Hyperstimulation Syndrome is a rare risk, which leads to ovarian enlargement, abdominal distention, and difficulty breathing. This can occur in 2% of patients and unfortunately is not preventable. If you gain more than 2 lbs. daily and are unable to void, you must notify our office immediately. At AFCT, every effort is taken to prevent the risk of ovarian hyperstimulation. Please notify our office if you are experiencing any other abnormal reactions or severe abdominal pain.
Letrozole - Injections

Ovulation Medication
Learning Center

Learn more about Letrozole and Clomid. If you have questions we have the anwers.
Advanced Fertility Center of Texas – Infertility Answers - Dr. Michael Allon

Scientific Research

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RBMO Oocyte Donation Programme
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