What is the annual decline in female fertility between 20 and 30 years of age?

From the Guidelines

Female fertility remains relatively stable between the ages of 20 and 30, with minimal decline during this decade, approximately 0.5-1% per year. This information is based on the most recent and highest quality study available, which indicates that the decline in fertility is gradual during this age range 1. The study from 2024 suggests that women in their 20s typically have a healthy reserve of eggs (ovarian reserve) and regular ovulation patterns, resulting in good chances for conception and healthy pregnancies.

Key Points to Consider

• The quality of eggs also remains relatively high during this period, which contributes to the minimal decline in fertility.
• The more significant decline in fertility begins after age 30, becoming more pronounced after 35, when both egg quantity and quality decrease more rapidly.
• Women concerned about fertility should know that while this slight decline exists in their 20s, it generally doesn't significantly impact conception rates for most healthy individuals, and this decade represents the biological peak of reproductive potential.

Factors Influencing Fertility Decline

• Age is a significant factor influencing fertility decline, with the median age of menopause being approximately 51 years in North America, but can vary from 40 to 60 years 1.
• No reliable laboratory tests are available to confirm definitive loss of fertility in a woman, and the assessment of follicle-stimulating hormone levels to determine when a woman is no longer fertile might not be accurate 1.

Clinical Implications

• Health care providers should consider the risks for becoming pregnant in a patient of advanced reproductive age, as well as any risks of continuing contraception until menopause.
• Pregnancies among women of advanced reproductive age are at higher risk for maternal complications and fetal complications, and risks associated with continuing contraception should also be considered 1.

From the Research

Female Fertility Decline

• The decline in female fertility between 20 and 30 years of age is not directly addressed in the provided studies 2, 3, 4, 5, 6.
• These studies focus on the effectiveness of various fertility treatments, such as gonadotropins, clomiphene citrate, and letrozole, in women with polycystic ovary syndrome (PCOS) or those undergoing in vitro fertilization (IVF).
• There is no explicit data on the yearly decline in female fertility between 20 and 30 years of age.

Fertility Treatments and Outcomes

• The use of clomiphene citrate or letrozole with gonadotropins may reduce the amount of gonadotropins required and the incidence of ovarian hyperstimulation syndrome (OHSS) 3, 4, 5, 6.
• However, the evidence on the effectiveness of these treatments in improving live birth rates or clinical pregnancy rates is unclear or of low quality 3, 4, 5, 6.
• The studies suggest that the addition of clomiphene citrate or letrozole to IVF cycles may have certain benefits, such as reducing OHSS incidence and gonadotropin consumption, but the overall effects on fertility outcomes are not well established 3, 4, 5, 6.

Limitations and Future Research

• The quality of the evidence in the provided studies is often limited by imprecision, inconsistency, and indirectness 2, 3, 4, 5, 6.
• Further research is needed to fully understand the effects of different fertility treatments on female fertility and to provide high-quality evidence for clinical decision-making 2, 3, 4, 5, 6.