The influence of age on fertility

Age is an important indicator for fertility. Find out more about how age affects your chances of getting pregnant here.

With advancing age, it happens more often that women do not ovulate during their menstrual cycle. This therefore reduces the chances of pregnancy. Age is one of the main determinants of fertility, especially in women. This biological fact feels unfair to many women and means that women often face a dilemma in their life choices.

The number of oocytes is finite

A girl is born with about 2 million eggs and does not produce new eggs in her lifetime. It is not that only during childbearing age an egg is lost only monthly, even before puberty about 1,000 eggs are lost monthly. During a woman's fertile life stage, best-quality eggs are released first during ovulation. Later in life, eggs are also somewhat older and of lower quality. This makes it more difficult to get pregnant at older ages and there is a higher risk of miscarriage or a baby with chromosomal disorders.

Around the age of 37, 90% of the original eggs have died and around 5-10 years before menopause, the number of eggs is almost completely exhausted. The uterus is less subject to ageing, so if a woman uses donor eggs (from a young donor) or her own (frozen at a younger age), there is a greater chance of pregnancy.

The magic number 35

More than half of women experience fertility problems after the age of 35 and after the age of 40 it is very difficult to conceive naturally, even if you are still very fit and living a healthy life at that age. Celebrities who hit the media with their motherhood later in life have usually resorted to fertility treatments or got pregnant through donor eggs. Generally, fertility treatments are more difficult in older age. The success of fertility treatments declines as you get older, so IVF and the like certainly do not simply guarantee a baby.

Dutch researchers once calculated that:

  • A woman who wants one child has a 90% chance of having a (naturally conceived baby) if she starts at age 32 - (at 35 if she is willing to resort to IVF)
  • A woman who wants two children has a 90% chance of having naturally conceived babies if she starts at age 27 - (at 31 if she is willing to resort to IVF)
  • A woman who wants three children has a 90% chance of having naturally conceived babies if she starts at age 23 (at 28 if she is willing to resort to IVF)

These are just averages of course, there are also women who can still have three naturally conceived children later in life and there are women who run into problems at a younger age. These figures do give an indication for couples who want multiple children. So, especially if you want multiple children, it is wise not to wait too long before having children. You don't always manage to get pregnant right away and by the time you have your 2nd, 3rd, ... child, you will soon be a few years older and so it may be more difficult to get pregnant and have a healthy pregnancy. Also, if the man is over 40, there is a higher risk of miscarriage if his (younger) partner is pregnant.

A good advice is to try to complete the childbearing process (the number of children you want) by the age of 35.

Are you ready to have kids?

Besides being less fertile later in life, there is also a higher risk of certain complications during pregnancy (e.g. high blood pressure, diabetes, miscarriage, ...). It may seem contradictory, but women over 35 are also more likely to have multiple pregnancies. This may seem nice, but a multiple pregnancy is extra stressful for your body, especially if you are over 35. Fortunately, even after the age of 30, most couples are still able to have a healthy baby after a healthy pregnancy.

The information on this website does not aim to influence your choices, but rather to inform you so that you can take this information into account when making choices. 

Disclaimer

The words "woman" and "man" are increasingly ambiguous concepts and should be avoided where possible. For ease of communication on this platform, we use the terms "woman" and "man" when providing information about biological processes. In this context, the term "woman" refers to a person with "female" sex characteristics (e.g., vulva, uterus, ovaries, etc.), and the term "man" refers to a person with "male" sex characteristics (e.g., penis, testes), although we are aware that:

1) There are many intersex individuals or individuals with variations in sex characteristics;

2) There are many people for whom gender identity does not fully correspond to or align with sex characteristics.

When providing information about relational aspects, however, the term "woman" does not refer to biological characteristics, but rather to gender. This also includes trans women (individuals who were legally registered as male at birth based on sex characteristics but have a female gender identity) and intersex individuals (born with variations in sex characteristics) who identify as women. Similarly, the term "man" refers to gender in this context, including trans men and intersex individuals who identify as men.