How much does age affect female fertility?

Age and Fertility

como la edad afecta fertilidad

Most women have heard of the concept of the 'biological clock' at some point. This idea can cause a lot of stress, especially when you are trying to get pregnant and not succeeding, or when you don't have a partner yet. Understanding how age can affect female fertility can help you make informed decisions about your reproductive future.

In youth, women have between 1 and 2 million eggs, and this number begins to decrease over time. This is because every month, thousands of eggs compete with each other to ovulate. This is different in men, who produce millions of new sperm every month, even though their fertility decreases with age. Have you heard of andropause?

A question I frequently ask my patients is: If a woman is young and healthy, what do you think her chances of getting pregnant are? The most common answer is 70-80%, but the monthly pregnancy rate is:

  • 25 years: 20-25%
  • 35 years: 15%
  • 40 years: 5%
  • 45 years: 1%

As you can see, human fertility is not very efficient. So, don't feel bad if you've been trying for a month or two and it hasn't worked. In fact, you are more likely to try and not succeed than to get pregnant. For this reason, women under 35 are advised to wait approximately 1 year, and those over 35, 6 months before seeking help from a fertility expert. Of course, if you already know that you have difficulty with your fertility (polycystic ovaries, endometriosis, a family history of losses, among others), it is highly recommended to consult with a professional.

The main reason why fertility decreases over the years is the reduction in egg production due to age. The exact reasons are not known, but it is believed that because these cells do not renew themselves, they accumulate damage from toxins, chemicals, and the environment, which affect their genetics and therefore do not allow the resulting embryo to develop. This same reason is why, after the age of 35, the likelihood of conceiving a baby with Down syndrome, better known as Trisomy 21, increases. Also, due to the increase in genetic errors, there is a higher rate of pregnancy loss, reaching up to 50% in patients over 45 years old.

But, not everything is bad news. Science and technology have advanced considerably in the last 10 years. For example, we used to talk about pregnancy rates, then in vitro fertilization rates of 20%, and today, through our program, we achieve rates higher than the rest of the region. There are also options like egg freezing to counter the age effect. Don't hesitate to contact me if you have any questions. Remember that being informed will help you make better decisions.