Egg freezing has become a popular option for women who want to preserve their fertility. While it was originally used for women undergoing treatments like chemotherapy that could harm their eggs, today many women choose it simply to extend their reproductive window.

In the U.S., it’s common for women to face a tough balancing act—pursuing education and careers while their ovarian reserve naturally begins to decline. Others may not be in the right life circumstances for pregnancy, whether due to relationships, finances, or personal goals. Egg freezing offers a way to take control of fertility and, in many cases, can be more cost-effective than trying to conceive later in life.

If you’ve been told to avoid estrogen, maybe due to a hormone-sensitive condition like breast cancer, you might wonder whether egg freezing is still an option. A common question we hear is: “Is estrogen used in the egg freezing process if someone can’t take estrogen?” The short answer is no-estrogen isn’t typically given as a medication during egg freezing.

What medications are used during the freezing process?

The main goal during egg freezing is to stimulate your ovaries to produce multiple eggs, mimicking your body’s natural cycle. This is done using hormone injections that encourage your body to ramp up egg production.

The process begins with daily injections of synthetic forms of the hormones your body naturally produces follicle stimulating hormone (FSH) and, in some instances, a combination of FSH and luteinizing hormone (LH). The exact combination and doses are individualized.

During this time, you’ll have frequent ultrasounds to confirm your follicles are growing appropriately. Once they reach the right size, you’ll get a “trigger shot”, which helps the eggs mature. The trigger shot is usually done with human chorionic gonadotropin (hCG) or a gonadotropin-releasing hormone (GnRH) agonist. Following this shot, ovulation is expected to occur within 36-40 hours, so your retrieval will be scheduled accordingly.

While estrogen levels naturally rise during this process, estrogen itself isn’t given as a medication, it’s just something your body naturally produces in response to stimulation medications.

What if I’ve been told I can’t take estrogen?

For women with conditions like breast cancer or where high levels of estrogen could be harmful, doctors use medications such as aromatase inhibitors to keep estrogen at safe levels. Aromatase inhibitors, such as letrozole, prevent the conversion of androgens (sex hormones) to estrogen, keeping estrogen levels low. This does not interfere with follicular growth which is still stimulated by the hormones (FSH and LH) given. This approach has been shown to be safe and effective, without compromising the number or quality of eggs retrieved.

The bottom line

Egg freezing is highly customizable and having a condition that limits estrogen use doesn’t mean egg freezing is off the table. The hardest part is often just starting the conversation with a fertility doctor. But once you do, you’ll find there are safe, effective options to make the process work for you.

Dr. Ido Feferkorn is a reproductive endocrinologist at Reproductive Medicine Group in Tampa. He specializes in treating patients with infertility, PCOS, endometriosis and recurrent pregnancy loss. He also has a special interest in fertility preservation. Dr. Feferkorn’s research has been presented in international conferences such as the American Society for Reproductive Medicine (ASRM) and European Society for Human Reproduction and Embryology (ESHRE). Dr. Feferkorn loves spending his free time with his wife and three kids. He chose REI because of the magic in seeing life created and accompanying the journey to parenthood.