The world of fertility meds can be a confusing and overwhelming place. With so many different treatment protocols and pharmaceutical options available, it’s vital to be in the care of a provider you trust. An interesting part of entering the world of fertility treatments is hearing other folks share their protocol successes or let downs. In doing so, you may have heard about a variety of ovulation induction medications, including Letrozole.

But how successful is Letrozole for fertility? Let's dig in and find out.  

Letrozole for Fertility

Letrozole is an oral medication which is used in fertility patients to help induce ovulation, to help assist in the production of multiple eggs, and to block estrogen production. By blocking estrogen production, taking oral Letrozole leads to an overproduction of follicle-stimulating hormone (FSH), which promotes healthy ovarian follicular development. Recent research has shown that Letrozole may be a better option than Clomid, another fertility medication which has often been used in similar cases, especially when it comes to improving pregnancy rates in patients with polycystic ovarian syndrome (PCOS)

A study presented at the 2012 American Association of Reproductive Medicine Conference found that 25% of patients treated with Letrozole had a live birth, compared to 16.8% of patients treated with Clomid. Additionally, follow-up studies have helped to confirm that Letrozole is more effective than Clomid for treating infertility in PCOS patients.

For the low-down on all things Letrozole, we spoke to Dr. Jacquelyn M. Shaw, MD, a provider at NYU Langone Fertility Center who specializes in reproductive endocrinology and  infertility.

woman sorting pills

What makes a fertility patient a good candidate for Letrozole?

Dr. Shaw: Letrozole can be great for a couple of different candidates, especially patients with polycystic ovarian syndrome (PCOS), medical patients where we need to keep estrogen levels low, or patients with decreased ovarian reserve (DOR).  

In PCOS patients, Letrozole alone can help recruitment of a dominant follicle and ovulation - which is often not happening for these patients. It can be a very effective treatment, especially for young patients with healthy eggs, who just can't ovulate on their own.  

Letrozole can also be used in patients undergoing controlled ovarian hyperstimulation with decreased ovarian reserve or expected low response to boost their natural (endogenous) production of follicle stimulating hormone (FSH) from the pituitary gland.  We typically give Letrozole in these cases for five days at the beginning of the cycle, either in conjunction with or staggered by a few days, with exogenous (aka shots) of FSH. This can help boost the number of follicles that are stimulated.

Finally, we can also use Letrozole to help keep estrogen levels lower during controlled ovarian hyperstimulation (like IVF or egg freezing).  Patients can take Letrozole daily during stimulation, and often even until the subsequent menses.  We commonly use this for patients undergoing medical fertility preservation - for example, for patients with estrogen positive breast cancers, or transgender patients with concerns about gender dysphoria related to estrogen.  

doctor taking patient notes

What success rates can be expected in patients taking Letrozole?

Dr. Shaw: Letrozole can work very well, especially for young PCOS patients. In addition to good pregnancy rates with ovulation induction, it also lowers the multi-gestation rates, which is often a risk in this population. So it works well, and is safer! 

In patients with a decreased ovarian reserve, Letrozole can reduce the amount of gonadotrophins needed during IVF or egg freezing and can be an effective protocol when combined with a lower dose of injectable gonadotrophins.  

What are some alternatives to using Letrozole for fertility?

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Dr. Shaw: While Clomid, another oral medication that can also help with infertility, has a limited number of recommended cycles (with no more than 6 cycles), Letrozole does not. We tend to aim for larger follicles with Letrozole when doing IVF or egg freezing - so you may expect to go an extra day of stimulation if using this as part of your protocol.

pharmacist talking with patients

Is Letrozole a good option for me? 

Infertility treatment protocols will always vary depending upon your specific case circumstances and diagnosis, so it must be kept in mind that there is certainly no “one-size-fits-all” path forward on your journey to growing your family. 

If you are a fertility patient with a diagnosis of PCOS, a patient diagnosed with decreased ovarian reserve, or a patient whose case needs to prioritize keeping your estrogen levels low, then Letrozole may be a great option for your treatment plan. Discussing your options with your provider, especially when it comes to the use of Letrozole vs. Clomid, would be a good first step.


Lindsey Williams is a library worker and writer who lives in Arizona with her husband and their dog, Peaches. After 5 years of trying to conceive with dual-factor infertility, she is currently expecting her first child conceived with the help of IVF.