Few topics generate more questions—and more anxiety—for women trying to conceive after 35 than egg quality. The phrase appears frequently in fertility discussions, but what does current science actually tell us about egg quality, how it changes with age, and what it means for conception? Understanding the research, without the alarm that often surrounds this topic, can help women have more informed conversations with fertility specialists.
The most important point to begin with: many women conceive naturally in their late 30s and early 40s, and egg quality is just one of many factors that influence fertility. Individual variation is significant, and a general picture based on population statistics does not predict any individual’s fertility.
What Research Tells Us About Eggs and Aging
Women are born with all the eggs they will ever have—approximately 1-2 million immature follicles at birth, according to the American College of Obstetricians and Gynecologists. Over a lifetime, this number declines through a natural process called atresia, with ovulation accounting for only a small fraction of the eggs that are lost. By the time a woman reaches her late 30s, she typically has a smaller remaining pool of follicles than in her 20s.
Beyond quantity, research has also examined the concept of egg “quality”—a term that broadly refers to chromosomal integrity, or whether an egg has the correct number of chromosomes. As women age, the likelihood of chromosomal errors in eggs appears to increase. This is thought to be related to the declining function of cellular machinery that oversees chromosomal separation during egg maturation. Chromosomal errors can reduce the likelihood of successful fertilization, implantation, and healthy embryo development, and are associated with higher rates of miscarriage in older mothers.
Understanding Chromosomal Integrity in Eggs
The specific type of chromosomal error most associated with maternal age is aneuploidy—where an egg ends up with too many or too few chromosomes rather than the typical complement of 23. Aneuploidy rates in eggs are estimated to be substantially higher in women in their late 30s and 40s compared to women in their 20s, based on research from IVF programs that routinely test embryos for chromosomal abnormalities.
However, it is important to understand what this research does and does not tell us. These studies predominantly come from IVF contexts where embryos are biopsied and tested—a population that may not represent all women trying to conceive. Additionally, even at 40, a meaningful proportion of eggs are chromosomally normal, and many women conceive healthy pregnancies at this age naturally. Statistics describe populations, not individuals.
For broader context on fertility changes with age, our article on what to know about trying to conceive after 35 covers related considerations.
Can Egg Quality Be Measured?
There is no direct test that measures “egg quality” in a clinical sense. The most commonly used measure of ovarian reserve—the remaining pool of eggs—is anti-Müllerian hormone (AMH), a protein produced by follicular cells in the ovaries. AMH levels decline with age and can give some indication of how many eggs remain, but AMH does not directly measure chromosomal quality or predict the chances of a successful pregnancy with certainty.
Antral follicle count (AFC), measured via transvaginal ultrasound, is another marker of ovarian reserve that some fertility specialists use. Like AMH, it reflects quantity rather than quality. A low AMH or AFC may mean fewer eggs are available in a given cycle, but women with lower ovarian reserve do conceive—the relationship between ovarian reserve markers and live birth rates is influenced by many additional factors.
Factors That May Influence Egg Health
While age is the factor most clearly associated with egg chromosomal integrity based on current research, other factors are also studied in the context of reproductive health. Research has explored the potential roles of oxidative stress, lifestyle factors such as smoking (which evidence fairly strongly associates with accelerated ovarian aging), and nutrition. However, for most modifiable lifestyle factors, the research is less definitive, and overstating the ability of any specific behavior to “improve egg quality” would go beyond what evidence currently supports.
Smoking is the lifestyle factor with the clearest evidence of harm to reproductive potential, including ovarian reserve. Beyond that, general recommendations that support overall health—adequate sleep, balanced nutrition, stress management, regular moderate physical activity—are reasonable and supported by evidence for general wellbeing, even if their direct effects on egg quality are not fully established.
You may also find it helpful to explore our overview of fertility health and lifestyle factors for additional context.
What This Means in Practice
If you are 35 or older and thinking about trying to conceive—or are already in the process—the most useful step is to discuss your individual situation with a reproductive endocrinologist or your OB/GYN. They can order relevant testing, interpret results in the context of your full health picture, and advise on whether any evaluation or support makes sense for your circumstances.
ACOG generally recommends that women under 35 who are not pregnant after 12 months of trying consult a specialist, while women 35 and older are typically advised to seek evaluation after 6 months. Women over 40 may be advised to seek a consultation even sooner.
Frequently Asked Questions
Is there anything I can do to improve my egg quality?
Research in this area is ongoing, and definitive conclusions about specific interventions are limited. Avoiding smoking is the lifestyle factor with the clearest evidence of benefit for ovarian health. Maintaining general health through balanced nutrition, adequate sleep, and stress management is supported by evidence for overall wellbeing and is generally reasonable to pursue. Specific supplements marketed for egg quality vary widely in evidence quality; discussing any supplement with a healthcare provider before starting is advisable.
Does a low AMH mean I can’t get pregnant?
Not necessarily. AMH reflects estimated ovarian reserve but does not directly predict whether a woman can conceive. Many women with lower AMH levels conceive naturally or with assistance. Conversely, AMH alone cannot predict how chromosomally healthy the remaining eggs are. A fertility specialist can help interpret AMH in the context of other fertility factors and your individual situation.
How much does egg quality actually affect miscarriage risk?
Chromosomal abnormalities in embryos are among the most common causes of early pregnancy loss, and the rate of chromosomally abnormal eggs does increase with maternal age. Research suggests this contributes to higher rates of miscarriage observed in women over 35 compared to younger women. However, many pregnancies after 35 proceed without chromosomal complications, and miscarriage has many potential causes beyond chromosomal factors alone.
When should I see a fertility specialist?
If you are 35-39 and have not conceived after 6 months of regular unprotected intercourse, ACOG recommends consulting a specialist. If you are 40 or older, many specialists suggest seeking evaluation after 3 months or even before beginning to try, given the more compressed timeline. If you have known health factors that may affect fertility, consulting a specialist proactively may be worthwhile regardless of how long you’ve been trying.
Key Takeaways
- Research indicates that chromosomal integrity of eggs tends to decline with age, which is associated with higher rates of conception difficulty and early pregnancy loss—but population statistics don’t predict individual outcomes, and many women conceive naturally after 35.
- There is no direct clinical test for “egg quality”; AMH and antral follicle count measure ovarian reserve quantity rather than chromosomal health.
- Smoking is the lifestyle factor with the clearest evidence of harm to ovarian health; the evidence for other specific interventions is less definitive.
- Women 35-39 are generally advised to consult a fertility specialist after 6 months of trying without conception; women 40+ after 3 months or sooner.
- An individualized assessment from a reproductive endocrinologist is the most useful tool for understanding your personal fertility picture.
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Individual health situations vary significantly. Always consult a qualified healthcare provider before making decisions related to your health, fertility, or pregnancy.
About the Author
Emily Carter is a women’s health writer focused on fertility, pregnancy after 35, and sleep changes in midlife. She writes research-informed, non-alarmist content to help women navigate reproductive and hormonal transitions with clarity and confidence.