Women’s age and fertility

A woman is born with all the eggs she is going to have in her lifetime. Her eggs age with her, decreasing in quality and quantity. Age is the single most important factor affecting a woman ‘s fertility. While good health improves the chance of getting pregnant and having a healthy baby, it doesn ‘t override the effects of age on a woman ‘s fertility.

A woman in her early to mid-20s has a 25–30% chance of getting pregnant every month. Fertility generally starts to slowly decline when a woman is in her early 30s, and after the age of 35 the decline speeds up. By age 40, the chance of getting pregnant in any monthly cycle is around 5%.

The Biological Clock

Women’s fertility is often described in terms of a “biological clock.” The peak reproductive years typically occur in the late teens to late 20s, during which the chances of conceiving are highest. Fertility begins to decline gradually in the early 30s, with a more significant decrease after age 35. By age 40, the likelihood of natural conception drops significantly.

Ovarian Reserve and Egg Quality

As women age, the quantity and quality of their eggs decline. This phenomenon is known as decreased ovarian reserve. Women are born with a finite number of eggs, and this number diminishes over time. Additionally, the quality of the remaining eggs may deteriorate, leading to a higher risk of chromosomal abnormalities and miscarriage.

Key Age Milestones

1. Under 30: Women in this age group generally have the highest fertility rates, with about 20% to 25% of cycles resulting in pregnancy.
2. Ages 30-34: Fertility starts to decline, but many women can still conceive naturally without significant issues.
3. Ages 35-39: The decline in fertility becomes more pronounced. The risk of miscarriage and genetic disorders (e.g., Down syndrome) increases as egg quality declines.
4. Ages 40 and Above: Fertility rates drop significantly. By age 40, the chance of natural conception is about 5% to 10% per cycle. Assisted reproductive technologies (ART) may become necessary for many women seeking to conceive.

Miscarriage and Pregnancy Complications

The risk of miscarriage also rises with age. For women in their 20s, the risk is approximately 10% to 15%, while for women over 40, it can be as high as 40% or more. Furthermore, older mothers are at an increased risk for complications during pregnancy, including gestational diabetes, hypertension, and preterm labor.

Assisted Reproductive Technologies (ART)

For women experiencing age-related fertility issues, ART options such as in vitro fertilization (IVF) can provide alternatives for conception. These technologies can help retrieve high-quality eggs and increase the chances of a successful pregnancy. Egg freezing (oocyte cryopreservation) is another option that allows women to preserve their eggs at a younger age for future use.

Lifestyle Factors

While age is a critical factor in fertility, lifestyle choices also play a significant role. Factors such as diet, exercise, smoking, alcohol consumption, and stress levels can influence reproductive health. Maintaining a healthy lifestyle can help optimize fertility, regardless of age.

Conclusion

Understanding the relationship between women’s age and fertility is crucial for those planning to conceive. As women age, they should be aware of the changes in their reproductive health and consider consulting with a healthcare provider for personalized guidance. Early planning and proactive measures can significantly enhance the chances of achieving a healthy pregnancy, regardless of age.

References

1. Zegers-Hochschild, F., Adamson, G. D., de Mouzon, J., et al. (2009). The International Committee for Monitoring Assisted Reproductive Technology (ICMART) and the World Health Organization (WHO) revised glossary of ART terminology. Fertility and Sterility, 92(5), 1520-1524. doi:10.1016/j.fertnstert.2009.09.016
2. Practice Committee of the American Society for Reproductive Medicine. (2013). Age and fertility: a committee opinion. Fertility and Sterility, 99(3), 588-589. doi:10.1016/j.fertnstert.2013.01.012
3. McLernon, D. J., et al. (2016). The effect of maternal age on the likelihood of live birth after in vitro fertilization: a national cohort study. Fertility and Sterility, 105(1), 192-199. doi:10.1016/j.fertnstert.2015.08.034
4. Noyes, N., et al. (2010). The effect of advanced maternal age on fertility and pregnancy outcomes. Journal of Reproductive Medicine, 55(5-6), 341-345.
5. Centers for Disease Control and Prevention. (2021). Reproductive health: a woman’s health. Retrieved from CDC website.