How age impacts your fertility
Fertility is a topic that affects millions of women at various stages of life. The biological clock is often talked about as it relates to age and fertility, but the science behind it can sometimes be unclear. In this article, we’ll explore how age impacts fertility in women, including key factors, common myths, and real-world statistics.
1. Fertility Peaks and Declines
Women are born with all the eggs they will ever have, typically around 1–2 million at birth. However, by puberty, this number drops to about 300,000 to 400,000, and only a fraction of these will be released during a woman’s reproductive years. Fertility in women generally peaks in their early 20s to early 30s, when egg quality and quantity are at their highest. After this peak, the decline is gradual at first, becoming more pronounced around age 35 and then accelerating after age 40.
Key Statistics on Age and Fertility:
According to Melbourne IVF, here are some key statistics
Under 30s: Women in their 20s have an approximately 25% chance of conceiving each month.
30s: In the early 30s, fertility remains relatively high, though it begins to slowly decline. Around 35, the rate of decline becomes steeper.
40s: After age 40, the chance of natural conception each month falls below 10%, primarily due to a decline in egg quality and quantity.
2. Egg Quality: The Biggest Hurdle
Egg quality is crucial in fertility. As women age, not only does the number of eggs decrease, but so does their quality. Chromosomal abnormalities become more common in older eggs, which can lead to increased risks of miscarriage and chromosomal disorders like Down syndrome. For instance, women under 30 have a lower risk of miscarriage, but the risk nearly doubles by the early 40s.
3. Age-Related Hormonal Changes
As women age, their hormonal profile shifts, particularly in the years leading up to menopause, known as perimenopause. The body's levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) change, while estrogen and progesterone levels fluctuate. In perimenopause, ovulation becomes less predictable, which can make conception more challenging even if pregnancy is still possible.
4. Lifestyle Factors and Age
The combination of age and lifestyle factors can also impact fertility. Women who maintain healthy lifestyles—such as regular exercise, a balanced diet, and avoiding smoking—may have better fertility outcomes than those who do not, even if they’re older. Still, age remains the most critical factor.
5. Fertility Treatment and Age
While age affects natural fertility, reproductive technology offers options. Assisted reproductive technologies (ART), such as in vitro fertilization (IVF), have helped many women conceive in their later reproductive years. However, the success rates of these treatments also decline with age. For instance, the success rate for IVF with a woman’s own eggs is around 40% for women under 35 but falls to below 10% by age 43. Egg donation can provide an alternative, as the age of the egg donor, rather than the recipient, determines much of the pregnancy success rate.
6. Pregnancy and Maternal Health Risks with Age
Pregnancy at an advanced maternal age comes with higher health risks, both for the mother and the baby. Conditions like gestational diabetes, preeclampsia, and preterm birth are more common in pregnancies after age 35. Babies born to older mothers also have a higher risk of low birth weight and other complications.
7. Emotional Impact and Societal Pressure
Many women feel the pressure of the "biological clock" and may face emotional challenges when trying to conceive later in life. Societal expectations and personal goals often influence the decision to delay childbearing. This can add stress and lead to increased anxiety, particularly if conception doesn’t happen as quickly as hoped.
Although age plays a significant role in fertility, it is important to remember that individual experiences vary.
Gaining knowledge such as tracking your Body Basal Temperature (see previous posts), getting blood and hormonal tests done, ultrasounds, and surrounding yourself with support systems, women can navigate their reproductive journey and make informed choices about family planning, regardless of their age.
References: Jean Hailes institute
Melbourne IVF
Monash IVF
