Egg freezing, technically known as oocyte cryopreservation, offers a way to preserve fertility for future use. This process involves retrieving a person’s eggs, freezing them at extremely low temperatures, and storing them until they are ready to attempt pregnancy. It has become an increasingly considered option for individuals seeking to extend their reproductive timeline, whether due to career aspirations, medical considerations, or personal circumstances. This scientific advancement provides more autonomy in family planning decisions.
General Recommendations for Egg Freezing
General recommendations for egg freezing vary based on age at the time of freezing. For individuals under 35, freezing around 15 mature eggs is often recommended to achieve a cumulative 80% chance of at least one live birth. This age group typically has higher quality eggs, allowing for a potentially lower target number.
As age advances, the recommended number of eggs to freeze increases to maintain similar probabilities of success. For those aged 35 to 37, aiming for approximately 20 to 25 mature eggs is suggested for an 80% chance of a live birth. Individuals between 38 and 40 years old may consider freezing around 30 eggs to achieve a 75% chance of a live birth. For those aged 40 to 42, freezing 30 or more eggs is often advised, though the chance of a live birth may decrease to about 50%.
Key Factors Determining Your Number
Beyond general recommendations, several individual factors significantly influence the specific number of eggs a person should aim to freeze. The age at which eggs are frozen is the most impactful variable, directly affecting both the quantity and quality of eggs retrieved. Younger individuals typically yield more eggs per cycle, and these eggs generally possess higher quality, which is crucial for successful outcomes later.
Ovarian reserve, a measure of the remaining egg supply, is another substantial factor. This is often assessed through tests like Anti-Müllerian Hormone (AMH) levels and Antral Follicle Count (AFC). AMH is a hormone produced by small follicles and indicates the number of eggs that can be stimulated and retrieved. A higher AMH level correlates with a greater potential egg yield in a freezing cycle.
AFC involves counting the small follicles visible on an ultrasound, representing the pool of eggs available for development. The number of antral follicles counted can approximate the number of eggs potentially collected. Both AMH and AFC help predict how many eggs might be retrieved in one cycle, guiding decisions on whether multiple freezing cycles may be necessary to reach a desired egg count.
Desired family size also influences the target number of frozen eggs. If the goal is to have more than one child, a higher number of frozen eggs may be advisable to increase the chances of multiple successful pregnancies. For example, planning for multiple children might suggest aiming for 20-30 frozen eggs.
Understanding Live Birth Success Rates
Recommendations for freezing eggs are based on statistical probabilities of achieving a live birth. The journey from a frozen egg to a baby involves several stages, each with its own attrition rate. Not all frozen eggs survive the thawing process. Modern vitrification, a rapid freezing method, has significantly improved survival rates, typically ranging from 90% to 95%.
Once thawed, the surviving eggs must be fertilized with sperm. The fertilization rate for thawed eggs is comparable to fresh eggs, often around 70%. Following successful fertilization, not all embryos will develop into a viable stage suitable for transfer. Approximately 40% of fertilized eggs may develop into good-quality embryos suitable for transfer.
The ultimate measure of success is the live birth rate. This rate is influenced by the individual’s age at the time of freezing. For women under 35 who freeze their eggs, a single thawed egg may have a 2% to 12% chance of resulting in a live birth. The overall chance of pregnancy after implantation of frozen eggs can range from 30% to 60%, depending on various factors.
Studies indicate that freezing a higher number of eggs significantly increases the cumulative chance of a live birth. While success rates are promising, it is important to understand that egg freezing enhances the chances of future pregnancy rather than guaranteeing it.
Consulting a Fertility Specialist
Given the individualized nature of fertility and the complexities of egg freezing, consulting a fertility specialist is an important step. While general guidelines exist, a reproductive endocrinologist can provide personalized guidance based on a thorough assessment. This consultation typically involves a review of medical history, specific fertility testing, and a detailed discussion of personal reproductive goals.
Fertility testing, including assessment of ovarian reserve markers like AMH and AFC, provides important information about a person’s current egg supply. This data helps the specialist estimate the number of eggs that can realistically be retrieved in a cycle and determine if multiple cycles might be needed. A specialist can also discuss the success rates relevant to an individual’s specific age and health profile.