Female Fertility By Age: When Does It Decline?
Understanding Female Fertility: How Age Influences Conception Likelihood
Fertility is top of mind and can sometimes be a key concern for many women who want to start a family. As women age, the likelihood of conception can change due to various biological factors. Understanding these changes can help women make informed decisions about their reproductive health and family planning.
The Peak Fertility Years
Women are born with a finite number of eggs. That’s right, at birth, a woman is born with the most eggs she will ever have. This number is approximately 1-2 million eggs, but this number decreases significantly by puberty. During the peak fertility years, typically between ages 20 and 30, women have the highest number of viable eggs. According to Dr. Aimee Eyvazzadeh, also known as "The Egg Whisperer," the quality and quantity of eggs are optimal during this period, leading to a higher likelihood of conception.
Decline in Fertility After Age 30
Around age 30, a woman's fertility starts to decline. By age 35, the decline becomes more pronounced. The American Society for Reproductive Medicine (ASRM) states that women in their mid-30s have about a 15-20% chance of conceiving per menstrual cycle. This decline is attributed to both the decreasing quantity and quality of eggs. Dr. Eyvazzadeh explains that as women age, their eggs are more likely to have chromosomal abnormalities, which can lead to difficulties in conceiving and an increased risk of miscarriage.
Fertility After Age 40
After age 40, fertility declines sharply. The ASRM notes that women over 40 have about a 5% chance of conceiving per cycle. Dr. Eyvazzadeh emphasizes that while some women can and do conceive naturally in their 40s, the likelihood is much lower, and assisted reproductive technologies (ART) such as in vitro fertilization (IVF) may be necessary.
Factors Influencing Age-Related Fertility Decline
Several factors contribute to the age-related decline in fertility:
Egg Quality and Quantity: As women age, their eggs accumulate genetic mutations, reducing their viability.
Hormonal Changes: Hormone levels fluctuate with age, affecting ovulation and the menstrual cycle.
Health Conditions: Conditions such as endometriosis and fibroids, which become more common with age, can impact fertility.
Options for Women
Understanding the impact of age on fertility is crucial for family planning. Women who wish to delay childbearing may consider options like egg freezing or embryo cryopreservation. This process involves harvesting and freezing eggs during peak fertility years, allowing women to use them later when they are ready to conceive.
It is also possible that a woman’s ovarian reserve may diminish sooner or later than other women. That’s why testing your fertility, and especially your AMH level, is so important. Anti-Müllerian Hormone (AMH) is a hormone produced by the ovarian follicles, and it serves as an important marker of ovarian reserve. In simpler terms, AMH levels decline as a woman ages. This decline correlates with the decrease in the number of eggs left in her ovarian reserve.
How AMH Levels Change with Age
AMH levels naturally decline as a woman ages. This decline correlates with the decrease in the number of viable eggs:
In Your 20s and Early 30s: During these years, AMH levels are generally at their peak. A higher AMH level indicates a larger ovarian reserve, which is associated with a higher likelihood of conception.
Mid-30s to Early 40s: Around age 35, AMH levels begin to decline more noticeably. This decline is gradual but significant, reflecting the reduction in the number of eggs.
After Age 40: The decline in AMH levels accelerates after age 40, indicating a much-reduced ovarian reserve. By the time a woman reaches menopause, AMH levels become undetectable, reflecting the near depletion of the ovarian reserve.
For women over 35 or those facing fertility challenges, consulting a fertility specialist can provide personalized guidance and explore potential treatments, including fertility medications, intrauterine insemination (IUI), and IVF.
Again, it is important to understand your fertility as early as possible, and to begin understanding where your body is at fertility-wise in your 20s’ and early 30s.
Some studies have also shown that AMH levels can vary significantly among different ethnic groups. For instance, research published in the journal Fertility and Sterility indicated that African American and Hispanic women tend to have lower AMH levels compared to Caucasian and Asian women of the same age group .
Conclusion
Age is a significant factor in female fertility, with the highest likelihood of conception occurring in the 20s and early 30s. As women age, fertility declines due to changes in egg quality and quantity. By understanding these changes and exploring available options, women can make informed decisions about their reproductive health and family planning.
For more information, resources such as the American Society for Reproductive Medicine and experts like Dr. Aimee Eyvazzadeh can provide valuable insights and support.
You can check out our at-home ovarian reserve test kit here or our comprehensive fertility test kit here.
Sources:
American Society for Reproductive Medicine (ASRM) - asrm.org
Dr. Aimee Eyvazzadeh, "The Egg Whisperer" - eggwhisperer.com
Fertility and Sterility