What is a Woman’s Age for Peak Fertility and When Does Fertility Begin to Diminish?
The women of 2018 are busy. Gone are the days of quiet obedience and limited ambitions. Women today are professors, lawyers, politicians, police officers, teachers, physicians, mothers, pilots, mathematicians, thought leaders, and much more. However, while modern women place more emphasis on intellectual development, career ambitions, and finding well-matched significant others, we are no less interested in motherhood and the gift of parenting a child.
Unfortunately, the evolution of women’s roles in society has not been accompanied by similar changes in women’s biological capacity for parenthood. Women often spend their twenties getting through school, building their careers, and attending social engagements. Ironically, by the time women have created a strong foundation of financial and emotional stability, their fertility has often begun to diminish.
PEAK FERTILITY AGE
Women’s fertility typically peaks in their late 20s. This occurs for two reasons: egg quantity and egg quality. Women are born with a limited number of eggs (about 2 million). This number decreases every month from birth through menopause as cohorts of eggs cycle through “readiness” and atresia. By the time a woman is 35, much of her egg supply is often gone. In addition, the eggs that remain sitting in a woman’s “supply stock” accumulate genetic errors over time so that the percentage of eggs containing chromosomal problems increases with age. At 40, approximately half of a woman’s eggs are aneuploid (contain genetic errors). Due to the constant decline in egg count and quality with age, women in their thirties and forties often face infertility, miscarriage, and an increased risk of birth of a child affected by a chromosomal abnormality.
Despite the discrepancy between women’s biological clocks and their evolving social and personal expectations, modern women need not compromise their desire for motherhood nor their personal and career goals. Women may elect to cryopreserve eggs now for use years in the future. These eggs will “behave” like eggs from a woman at the age of freezing- not the age at which she elects to become pregnant. In other words, freezing eggs at a young age can increase a woman’s chance of a healthy, genetically normal baby even if she elects to use those eggs in her late 30s or 40s. Women who have delayed parenthood for any reason may pursue fertility treatments such as artificial insemination or in vitro fertilization (IVF) to improve their chance of conception. Women who undergo IVF may elect to have their embryos tested for genetic abnormalities prior to transfer- thereby decreasing their chance of having a miscarriage or giving birth to a child with chromosomal abnormalities.
In this way, fertility treatments can be liberating. They enable women to pursue all of their dreams- from having the corner office, to owning a home, to making lieutenant, to being a parent. Fertility treatments can be trans-formative, I have seen this many times in my practice. That being said, patients who want to nurture all of their goals are best advised to seek evaluation of their fertility at a young age. Even if they do not wish to pursue pregnancy in the near future, a fertility evaluation will help them to maximize their chance of motherhood down the road.