We shed light on similarities & differences between the cryopreservation options

Women who are looking for alternative conception methods so they can postpone getting pregnant until later in life face the dilemma of choosing between freezing their eggs and freezing embryos. These two separate processes each aims to preserve a woman’s ability to carry and have a baby with in vitro fertilization (IVF), but each also has distinct advantages and disadvantages.

We’re helping clarify the difference between freezing eggs and embryo freezing so readers can make more informed decisions.

Fertility preservation options

A woman is born with all the eggs she will ever have. The quality of eggs, with usually one being released a month, diminish over time. So the younger a person is when trying to get pregnant naturally, the higher the chance of a successful, healthy pregnancy. Along with age, certain treatments such as those for cancer can make a person infertile.

There are also many personal or professional reasons a person might choose to freeze their eggs or embryos: military deployment, lack of a partner, a recent divorce, financial uncertainty and more.

Difference between the egg and embryo freezing process

In terms of the process, both preservation techniques are similar. First, medications are taken to stimulate a woman’s ovaries to simultaneously mature multiple eggs. Our fertility specialist monitors the woman’s egg development to determine when the ovaries are ready for egg retrieval.

These eggs are then harvested from the body in a minor surgical procedure and transferred to our embryology laboratory for testing. After evaluation, about three-quarters of retrieved eggs are generally considered mature and healthy enough to result in an embryo when fertilized through IVF.

In egg freezing, the most mature and high-quality eggs are cryopreserved after retrieval. They can be thawed later and fertilized with sperm, either from a partner, a known donor or an unknown donor. Keep in mind that not all of the eggs will become embryos after thawing and attempted fertilization.

The fundamental difference in embryo freezing is that after retrieval, an egg is fertilized with sperm in a lab. Fertilized eggs hopefully develop into embryos, and those that do are frozen – in essence, completing two-thirds of an IVF treatment. These embryos can be thawed and used later during the embryo implantation part of IVF.

Choosing between egg freezing and embryo freezing

Let’s talk about the pros and cons of each process to see which one is a better option for an individual’s unique goals.

Egg freezing pros

• No partner (e.g., sperm) is needed at the time of freezing. This option allows all women, who are either single or in relationships, more control of their parenting journey.
• Ideal option for same-sex couples or couples with low sperm quality.
• Typically cheaper to freeze eggs.

Egg freezing cons

• Requires more eggs to be retrieved and frozen to ensure high enough survival odds for treatment.
• Would require a partner or donor for future treatment.

Embryo freezing pros

• If a couple knows they eventually want to become parents but the timing just isn’t quite right, embryo freezing and banking may be the most efficient procedure as it essentially stops the biological clock for both partners.
• Embryos are easier to freeze than eggs.
• Since eggs are already fertilized and the number of viable embryos is known, fewer samples are cryopreserved.

Embryo freezing cons

• More upfront cost, as many preimplantation procedures such as embryo preimplantation genetic testing, intracytoplasmic sperm injection (ICSI), fertilization, etc. are completed prior to freezing.
• The couple risks having a separation, differing opinions later in life about parenting, and legal and/or ownership disputes.

What next?

If a person is looking to delay getting pregnant for the later stages of life, either choice is a good option. Frozen egg or embryo storage can keep both safe and secure indefinitely. The most important decision is making a decision while egg quality is still viable.

For those considering fertility preservation, seek the guidance of a fertility specialist or fertility counselor. They can guide you through the emotional, financial and medical impact of options.