Predicting Fertility

Understanding Age and Fertility

More individuals are choosing to build their families in their 30s and 40s. In the United States, about 20% of first-time births now occur in people over the age of 35. While many go on to conceive and have healthy pregnancies, it's important to recognize that fertility potential generally declines with age. In fact, about one-third of individuals or couples in which the egg provider is over 35 experience fertility challenges.

How Age Can Impact Fertility

As people age, several changes can occur that may affect fertility:

• A decrease in the number of healthy eggs (oocytes)
• Lower chances of achieving pregnancy
• Higher risk of miscarriage and genetic conditions in offspring

Although fertility declines with age for everyone, the age at which a person can no longer conceive varies widely. There is no single test that can predict the ability to become pregnant, but ovarian reserve testing can provide insight into egg quantity.

Ovarian Reserve Testing

Ovarian reserve tests assess the remaining egg supply and include the following:

• Hormone blood levels:
  • Anti-Müllerian Hormone (AMH): Produced by follicles and closely related to the number of eggs remaining. This test can be done at any time during the menstrual cycle.
  • Follicle-Stimulating Hormone (FSH) and Estradiol: These hormones help assess how the brain and ovaries are communicating. They are typically measured on day 2 or 3 of the cycle.
• Transvaginal Ultrasound (Antral Follicle Count):
   This imaging test counts the number of small follicles (2–10mm) in the ovaries. These are called antral follicles, and they contain developing eggs. The ultrasound is usually performed on day 2 or 3 of the cycle.

It’s important to note that while abnormal test results may indicate diminished ovarian reserve, they cannot definitively predict who will or will not conceive.

Considering Egg (Oocyte) Freezing

For individuals with signs of declining ovarian reserve—or those who wish to preserve their fertility for future use—oocyte (egg) freezing may be an option to improve the chance of having a biologically related child later in life. The likelihood of future success depends on:

• The age at which the eggs are frozen
• The number of mature eggs frozen
• How well the eggs survive the freezing and thawing process

To explore your chances of success based on age and number of eggs, you can use tools like the egg freezing calculator.

However, there are no guarantees, and some individuals may experience regret or emotional complexity after pursuing egg freezing. We encourage thoughtful discussion with your provider.

Many obstetrician-gynecologists can order and interpret ovarian reserve tests. However, a reproductive endocrinologist (fertility specialist) can help you fully understand your fertility profile and discuss whether oocyte freezing or other family-building options may be right for you.