When it comes to fertility, age is one of the most talked-about factors. Many people today are choosing to start families later in life, whether for career goals, financial stability, or personal reasons. While there’s no single “right” timeline for parenthood, it’s true that fertility changes over time.
Fertility is shaped by a combination of biology, health, and timing, and those factors shift throughout your reproductive years. From the higher chances of conception in your 20s to the more noticeable changes that can occur in your 30s and 40s, knowing what typically happens at each stage can provide clarity, reduce uncertainty, and help you feel more prepared as you think about growing your family.
How Female Fertility Works
Female fertility is closely tied to both the number of eggs a woman has and the quality of those eggs. While these two factors are related, they are not the same, and both play an important role in the ability to conceive and maintain a healthy pregnancy.
Egg Quantity: Your Ovarian Reserve
Women are born with all the eggs they will ever have. Before birth, that number is in the millions, but it naturally declines over time. By the time menstruation begins, most women have approximately 300,000 to 500,000 eggs remaining. From there, the supply continues to decrease with age.
Each menstrual cycle, the body prepares a group of eggs, and typically one is released during ovulation. The rest are lost through a natural process called atresia. This means egg loss happens every month—not just when ovulation occurs—which is why the ovarian reserve steadily declines over the years.
Key Points About Egg Quantity:
- Egg numbers decrease continuously from birth through menopause
- By age 30, only about 12% of a woman’s maximum egg reserve remains, and by age 40, just 3% remains
- A lower egg count does not mean pregnancy is impossible, but it can affect how long it takes to conceive
Egg Quality: Why Age Matters More Than You Think
Egg quality refers to how genetically healthy an egg is and whether it can be fertilized, implanted in the uterus, and develop into a healthy pregnancy.
As women get older, eggs are more likely to have chromosomal abnormalities. These changes can make it harder to conceive and increase the risk of miscarriage. This is one of the main reasons fertility declines with age, even when menstrual cycles remain regular.
Important Things to Know About Egg Quality
- Egg quality naturally declines over time
- Chromosomal abnormalities in eggs increase, which contributes to pregnancy loss
- Miscarriage risk rises from about 12% in the 20s to nearly 37% by age 40-44
- By age 40, many women have a higher percentage of abnormal eggs
Fertility is Individual
Although age is a major factor in fertility, it’s not the whole story. Hormone levels, underlying health conditions, lifestyle factors, and genetics all play a role. Some women may experience fertility challenges earlier in life, while others may conceive more easily later on. This is why fertility care is most effective when it’s personalized, not based on age alone.
Understanding how egg quantity and quality change over time provides helpful context, but it’s only one piece of the fertility picture. How those changes affect you personally can vary, which is why fertility testing and expert guidance can be so valuable at any stage.
Understanding Fertility in Your 20s
For many women, the 20s are considered the years of peak fertility. During this time, egg quantity and egg quality are generally at their highest, which means the body is biologically well-positioned for conception. However, while the chances of getting pregnant are typically better in this decade, fertility is never guaranteed, and challenges can still occur.
Chances of Getting Pregnant in Your 20s
A healthy woman in her mid-20s has a strong chance of becoming pregnant within a year of trying, assuming regular ovulation and no underlying fertility concerns. On average, women in their 20s may have a 20-25% chance of conceiving each menstrual cycle, which is why many pregnancies happen relatively quickly during this stage of life.
Egg Quality and Pregnancy Outcomes
Egg quality is typically excellent in the 20s, which plays a major role in successful fertilization and healthy embryo development. Because chromosomal abnormalities are less common at younger ages, the risk of miscarriage and genetic conditions is generally lower compared to later decades.
Fertility Challenges That Can Still Occur
Even during peak fertility years, some women experience difficulty conceiving. Age alone doesn’t prevent conditions that affect reproductive health.
Common fertility-related issues in the 20s may include:
- Polycystic ovary syndrome (PCOS)
- Endometriosis
- Irregular ovulation or hormone imbalances
- Thyroid disorders
- Male factor infertility
Because fertility involves both partners, difficulty conceiving is not always related to female age or egg health, which is why we may also recommend male fertility testing in the early stages of your journey.
Fertility in Your 30s: Gradual Decline and Key Turning Points
For many women, the 30s are a time of transition when it comes to fertility. While pregnancy is still very possible throughout this decade, subtle biological changes begin to occur.
Many women continue to ovulate regularly, and egg quality is generally good. However, by age 35, the monthly chance of conceiving naturally is around 15% per cycle.
Your 35th Birthday is a Fertility Milestone
Age 35 doesn’t mean fertility stops, but because the rate of decline becomes more noticeable. After this point, both egg quantity and egg quality decrease more rapidly.
As egg quality declines, eggs are more likely to have chromosomal abnormalities. This affects fertilization, embryo development, and implantation, and it also increases the risk of miscarriage. While many women do conceive and have healthy pregnancies after 35, it may take longer and require closer monitoring or additional support.
Fertility Testing and Treatment in Your 30s
Because fertility changes accelerate during this decade, earlier evaluation is often recommended. This can provide insight into:
- Ovarian reserve (including AMH levels)
- Ovulation patterns and hormone balance
- Uterine and tubal health
If treatment is needed, options such as intrauterine insemination (IUI) or in vitro fertilization (IVF) may be recommended depending on individual circumstances.
Egg Freezing is a Proactive Option
For women who aren’t ready to start a family but want to keep future options open, egg freezing (cryopreservation) can be an empowering option. Because egg quality is generally higher earlier in your 30s, freezing eggs at this stage may help preserve younger, healthier eggs for use later in life.
Know What’s Possible with Fertility in Your 40s
As women enter their 40s, the number of remaining eggs is lower, and egg quality continues to decline. This means that the chance of getting pregnant in any given menstrual cycle is reduced compared to the 30s. On average, women in their early 40s may have a lower monthly chance of conception, and it often takes longer to become pregnant naturally.
That said, regular menstrual cycles can still indicate ongoing ovulation, and some women do conceive without medical intervention.
Egg Quality, Miscarriage Risk, and Healthy Pregnancy
Egg quality is one of the most important factors affecting fertility in the 40s. As chromosomal abnormalities become more common with age, there is a higher risk of miscarriage. However, many women in their 40s go on to have healthy pregnancies and healthy babies, particularly when pregnancies are closely monitored and supported by experienced care teams.
It’s also worth noting that advances in genetic testing and prenatal care have improved pregnancy outcomes and provided valuable reassurance for many patients in this age group.
Fertility Care and Treatment Options in Your 40s
Timely support can make a meaningful difference in your fertility journey. At this age, we create a plan that aligns with your health, goals, and timeline.
- IVF may help identify and transfer embryos with the highest potential for success
- Some patients may explore additional options, such as donor eggs, depending on individual medical factors
Working with an experienced fertility team can help you better understand your options and move forward with confidence, whether you are just beginning to consider pregnancy or have already been trying to conceive.
Take the Next Step With Alabama Center for Reproductive Medicine
No matter your age or where you are in your fertility journey, you deserve clear answers, compassionate care, and a team that listens. At ACRM, patients receive individualized fertility care designed to support their unique goals, whether that means trying to conceive naturally, exploring fertility treatment options, or gaining a better understanding of their reproductive health.
Our experienced fertility specialists combine advanced reproductive technology with a thoughtful, patient-first approach to help women and couples at every stage of life. If you have questions about age and fertility or have been struggling to conceive, we’re here to help you explore your options confidently. To schedule an in-depth phone consultation with our team, call (205) 307-0484 and take the next step toward growing your family.