Letrozole, also used under the trade name Famara (Femara), is an oral medication that functions as an aromatase inhibitor. This helps prevent the conversion of androgen to estrogen, effectively suppressing estrogen production. Women who have been diagnosed with hormone-receptor-positive, early-stage breast cancer often take the drug after surgery, chemotherapy or radiation to help reduce the risk of cancer returning. Because Letrozole specifically reduces estradiol levels in the body, it caught the attention of reproductive endocrinologists.
In the simplest terms, Letrozole induces ovulation. As estrogen levels drop, the pituitary gland senses this decrease and secretes the follicle stimulating hormone (FSH) to increase estrogen in an attempt to maintain optimum hormonal balance. By generating FSH, the ovaries are stimulated to grow more follicles. Letrozole boosts this growth and release of eggs in women who are anovulatory, or not ovulating, and can cause superovulation in women who are already able to ovulate. In both cases, it increases the chances of natural conception. Another benefit of Letrozole for fertility? It improves endometrial thickness.
Historically, Clomid has been a popular first option to try during fertility treatment, especially for women with Polycystic Ovarian Syndrome (PCOS). Clomid is under a class of medication called clomiphene citrate, which lasts in the body for an extended period of time and may actually have a negative effect on cervical mucus and uterine lining. Research is beginning to show that women with PCOS do not respond well to it.
And, while a 2009 study indicated Letrozole had no advantage over Clomid in women with PCOS, a study in 2014 showed Letrozole to have higher live-birth and ovulation rates among infertile women with PCOS.
The majority of the data on the side effects of Letrozole come from women who use it as part of a five-year cancer treatment regimen. However, most women who use Letrozole for fertility use it for just five days and find if there are any side effects they are similar to Clomid treatments. Letrozole side effects include:
Some women also find that infertility drugs that improve ovulation may also result in anxiety, mood swings, and irritability.
It’s critical to note that Letrozole cannot be taken during pregnancy or breastfeeding. Research shows it may cause damage to developing embryos, but because it is taken before pregnancy, it does not increase the risk of birth defects.
A 2014 study dedicated to this research found that congenital and chromosomal abnormalities were found in 5 out of 201 (2.5%) of babies conceived with the help of Letrozole, compared to 5 of 171 (2.9%) of babies conceived naturally and 10 of 251 babies (3.9%) conceived with Clomiphene. The conclusion showed no significant difference in the overall rate of congenital malformations for children born to mothers who conceived naturally versus using Letrozole or Clomiphene treatments.
As with any infertility statistic, a number of factors must be taken into consideration when it comes to interpreting the data. A 2012 study showed that 25% of women treated with Letrozole had a live birth, compared to 16.8% of those on Clomid. While Letrozole does appear to have an advantage, it doesn’t factor in other potential roadblocks on the way to a healthy baby.
What are Letrozole alternatives? Well, if this route has been unsuccessful, it’s time to consider a new path. Since Letrozole only addresses ovulation, it doesn’t impact other potential fertility issues. The odds of achieving a pregnancy are best when both the egg and sperm come from young, healthy sources that have met specific medical criteria. This may mean using an egg donor; according to the US Centers for Disease Control and Prevention, IVF with a donor egg has a success rate of 52%, which is the highest of any fertility treatment. Higher still is the rate of success with a surrogate. IVF clinics in the US have a surrogacy success rate of about 75%, and that number can increase as high as 95% for a birth once the gestational carrier is pregnant.
It’s important to understand your options when it comes to infertility treatment. If you’ve considered surrogacy or an egg donor to build your family, contact ConceiveAbilities. Our team is excited to share more information, success stories and support as you make your decision.
All Things Conceivable is a blog dedicated to sharing the knowledge and expert opinions of the dedicated team at ConceiveAbilities, a Chicago-based egg donation and surrogacy agency.