Age-Related Fertility Decline

Excerpt

Females are born with a finite number of oocytes. In contrast to their male counterparts, females most likely do not create new gametes throughout their lifetime. The number of oocytes peaks in utero at around 20 weeks gestation and subsequently decreases consistently until approximately age 32. At this age, the number of oocytes decreases at a greater rate until age 37, after which oocyte numbers drop even more rapidly.

As American women focus more on careers and other life goals, the initial childbearing age is being pushed back. In women older than 30, delivery of the first child increased 6-fold between 1970 and 2002. The number of women aged 30 to 34 years delivering their first child rose by 28% between 2000 and 2014; the number of women aged 35 or older rose by 23%. Accordingly, there have been age-related fertility decline problems increasing among our population, and fecundability has decreased. Therefore, patient counseling and education on age-related fertility decline is a critical aspect of family planning. Clinicians have an essential role in educating patients regarding their potential fecundity starting at an early age and referring patients for further workup promptly when indicated. Natural fertility tends to be overestimated, and delayed childbearing is often overlooked as a risk for infertility.

Clinicians should have a solid working knowledge of the general trend of age-related fertility decline so that appropriate counseling can be undertaken with patients before they reach the point of decreased or even irreversible loss of fertility. Testing women for decreased ovarian reserve may be recommended in women aged ≥35 years attempting conception without success after 6 months. This age parameter may be lowered for women with diminished ovarian reserve risk factors (eg, having only 1 ovary, a history of ovarian surgery, exposure to chemotherapy or radiation, and unexplained infertility). In any patient aged 40 or older seeking infertility care, recommending evaluation by a reproductive endocrinologist is appropriate. Management primarily involves discussing the decreasing pregnancy rates for patients in their 30s and 40s, natural and assisted reproductive options, and shared decision-making as a part of routine family planning counseling.