Egg Freezing: Fertility Preservation and Oocyte Cryopreservation

Egg freezing, also called oocyte cryopreservation, is a procedure in which a woman’s eggs are retrieved, preserved by freezing, and stored for use at a later time. It is a fertility preservation technique that allows women to delay childbirth until they are ready or when they face medical conditions that could affect their fertility.

The egg-freezing process involves stimulating the ovaries with hormones to produce multiple eggs. The eggs are collected using a minimally invasive surgical technique known as follicular aspiration. The eggs are then flash-frozen using vitrification, which preserves them by quickly freezing them to prevent ice crystal formation. The frozen eggs are then stored in a cryogenic freezer at -196 degrees Celsius until needed.

Egg freezing has gained popularity in recent years due to technological advances, changes in social attitudes towards motherhood and career choices, and the increasing age at which women have children. According to the American Society for Reproductive Medicine (ASRM), egg freezing is no longer considered experimental and is a widely accepted method of fertility preservation.

Who Can Benefit from Egg Freezing?

Egg freezing provides women the opportunity to postpone having children, either by choice or due to medical conditions that may impact fertility. Some reasons women may choose to freeze their eggs include the following.

• Medical Reasons: Women scheduled for chemotherapy, radiation, or other medical treatments that could affect fertility may opt to freeze their eggs beforehand. Such treatments can harm the ovaries and lower fertility, potentially making natural conception difficult or impossible later.
• Social Reasons: Women who are not yet ready to start a family but want to ensure their ability to have children later in life may choose to freeze their eggs. This includes women who want to focus on their careers, education, travel, or wait for the right partner.
• Age-related Infertility: As women age, the quality and quantity of their eggs decrease, leading to a decline in fertility. Egg freezing enables women to safeguard their fertility at a younger age, increasing the likelihood of having healthy eggs in the future.
• LGBTQ+ Couples: Egg freezing is also an option for LGBTQ+ couples wanting a biological child. Women in same-sex relationships or transgender men can use frozen eggs to conceive with the help of a sperm donor.

What is the Success Rate of Egg Freezing?

The likelihood of a successful outcome with egg freezing is influenced by several factors, including the age of the woman when the eggs are frozen, the health and quality of the eggs, and how many eggs are harvested. According to the ASRM, the chance of a frozen egg resulting in a live birth ranges from 2% to 12% per egg, depending on the woman’s age when the eggs were frozen.

The best time to freeze eggs is before the age of 35, as the quality and quantity of eggs decline after this age. Women who preserve their eggs before turning 35 generally have better chances of successful conception than those who do so at an older age.

What are the Risks and Side Effects?

Egg freezing is generally considered safe and does not cause any long-term health risks. However, like any medical procedure, there are some risks and side effects associated with egg freezing. These include:

• Ovarian Hyperstimulation Syndrome (OHSS): The hormones used to stimulate the ovaries can cause OHSS, a condition where the ovaries become swollen and painful. In uncommon instances, OHSS may cause severe complications like blood clots, kidney failure, or breathing difficulties.
• Multiple Pregnancy: Retrieving and using multiple eggs in IVF increases the possibility of twins or higher-order pregnancies, which can carry potential health risks for both mother and children.
• Emotional and Psychological Effects: Egg freezing can be emotionally and psychologically challenging. It can cause stress, anxiety, and depression in some women, especially if they face unexpected challenges or have difficulty conceiving later on.
• Cost: Egg freezing can be expensive and may not be covered by insurance. Women may also need to pay for storage fees and fertility treatments later.

Despite these risks and challenges, many women find egg freezing a valuable option for preserving their fertility and having the option to conceive later in life.

The Process Involved in Egg Freezing

The egg-freezing process involves several steps, including ovarian stimulation and monitoring, egg retrieval, and egg freezing.

Ovarian Stimulation and Monitoring

The first step in the egg-freezing process is ovarian stimulation. First, the woman is given hormones to stimulate the ovaries to produce multiple eggs. This is done using injections of follicle-stimulating hormone (FSH) and luteinising hormone (LH) over a period of about two weeks.

During this time, the woman’s response to the hormones is monitored closely through blood tests and ultrasounds to ensure that the ovaries produce multiple mature eggs. The dosage of hormones may be adjusted based on the woman’s response to the treatment.

Egg Retrieval

When the eggs develop to the right size and maturity, an egg retrieval procedure is performed on the woman. This procedure is a minimally invasive surgery carried out while the patient is under sedation or general anaesthesia.

This is a minimally invasive surgery carried out while the patient is under sedation or general anaesthesia. The eggs are gathered into a test tube and promptly transferred to a sterile container for delivery to the laboratory.

Egg Freezing

The retrieved eggs are preserved through a freezing technique known as vitrification. This involves quickly freezing the eggs to prevent ice crystal formation, which could damage the eggs. The eggs are immersed in a protective solution and kept in a cryogenic freezer at –196°C until they are required.

The entire egg-freezing process usually spans two to three weeks, from the beginning of ovarian stimulation to the completion of egg retrieval and freezing.

Who to Consult for Egg Freezing?

Specialised doctors called reproductive endocrinologists undergo extensive training in fertility and assisted reproductive technologies, including egg freezing and in vitro fertilisation.