How Age Affects Fertility for Women and Men

Starting a family is an important milestone, but the progress of age is a vital factor in fertility for both women and men. Understanding how age influences reproductive potential can empower people to make informed decisions about family planning.

 

Female Fertility and Age

Women are born with a finite number of eggs stored in their ovaries. Unlike men, women do not produce new eggs during their lifetime. The number and quality of these eggs decline naturally as a woman ages.

• Peak Fertility Years: Women’s fertility peaks in their late teens to late 20s. During this time, the chance of conceiving each menstrual cycle is about 20-30%.​
• Gradual Decline After 30: Starting around age 30, fertility begins a slow decline. By the early to mid-30s, this decline becomes more noticeable.​
• Rapid Decline After 35: The fertility decline speeds up after age 35. The chance of getting pregnant per cycle drops significantly, with only about 66% of women conceiving within a year at age 35, decreasing further to approximately 44% by age 40.​
• Egg Quality and Quantity: Both the number and quality of eggs decrease with age. Older eggs are more likely to have chromosomal abnormalities, increasing risks for miscarriage, genetic disorders, and difficulties in conceiving.​
• Increased Pregnancy Risks: Besides reduced fertility, older women face higher risks of pregnancy complications such as miscarriages, stillbirth, preterm birth, and chromosomal abnormalities like Down syndrome.​
• Additional Factors: Conditions like endometriosis, uterine fibroids, and irregular menstrual cycles become more common with age, further impacting fertility.​

 

Male Fertility and Age

Unlike women, men continuously produce sperm throughout their lives. However, male fertility also declines with age, but generally more gradually and later than in women.

• Sperm Quality Declines: As men age, sperm motility (movement), volume, and morphology (shape) tend to decrease. These changes reduce the chances of successful fertilization.​
• Longer Time to Conceive: Older men take longer to impregnate their partners. For example, men over 45 may take five times longer than men under 25 to achieve pregnancy with their partners.​
• Increased Genetic Risks: Older paternal age is associated with higher risks of genetic mutations in sperm, which can increase the risk of autism, schizophrenia, Down syndrome, and other developmental disorders in children.​
• Subtle Fertility Decline: Although male fertility decline is often less pronounced, studies show men over 45 have increased risks of miscarriage and offspring health complications.​

 

Combined Effect of Age on Couples’ Fertility

The age of both partners influences fertility; older men combined with older women further decrease the couple’s overall chances of conception. Some studies suggest the male partner’s age impacts female fertility more significantly when the female partner is in her mid-30s or older.​

 

Recommendations and Considerations

• Women under 35 who have not conceived after 12 months of regular unprotected intercourse are usually advised to seek a fertility evaluation. For those 35 and older, evaluation after 6 months is recommended.​
• Men over 40 or couples where both partners are older should consider earlier fertility assessments due to higher risks and declining chances.​
• Fertility treatments like IVF can help overcome age-related fertility issues but have lower success rates with increasing female age.​
• Awareness of age-related fertility decline remains low globally; educating people on reproductive aging can aid in family planning decisions.​

 

Conclusion

Age is the most crucial factor affecting fertility for women and a significant factor for men as well. Women’s fertility peaks in their 20s, declines gradually after 30, and more sharply after 35, largely due to the diminishing quantity and quality of eggs. Men experience a slower decline in sperm quality and an increase in genetic risks as they age, affecting fertility and child health. Couples should consider age-related fertility changes when planning to conceive and seek timely medical advice if needed.

This comprehensive overview of age’s impact on fertility helps clarify why timing matters for family planning and highlights the biological and health factors behind fertility decline in both sexes.