Can I get pregnant after 40?

In modern society, age-related infertility is quite common as, for various reasons, many women wait until the age of 35-40 to start a family plan.

It is important to understand that fertility declines due to the normal reduction in the number of eggs remaining in the ovaries and their quality over time.

 

Female fertility in numbers

A woman’s best reproductive years are in her 20s. Fertility gradually declines in the 30s, especially after 35. Every month that she tries, a healthy, fertile woman in her 30s has a 20% chance of getting pregnant. This means that for every 100 fertile 30-year-old women who try to get pregnant in 1 cycle, 20 will be successful and the other 80 will have to try again. At age 40, a woman’s chance is less than 5% per cycle, so fewer than 5 in 100 women are expected to be successful each month. We also need to understand that women do not remain fertile until menopause. The average age for menopause is 51, but most women cannot have a successful pregnancy after their 40-41s. These rates apply to both natural conception and conception using fertility treatments, including in vitro fertilization (IVF). Although media and social media stories may lead couples to believe that they will be able to use fertility treatments like IVF forever, a woman’s age affects the success rates of these treatments. We know, for example, that IVF success rates after 42 are 4-5%

 

How does age affect egg quantity and quality?

Women are less likely to get pregnant and more likely to have miscarriages because the quality of the eggs decreases (as well as their number). These changes occur more as a woman reaches her mid-to-late 30s. We can therefore say that age is the most important predictor of egg quality. An important change in egg quality is the incidence of genetic abnormalities called aneuploidy (too many or too few chromosomes in the egg). At fertilization, a normal egg should have 23 chromosomes, so that when fertilized by a sperm that also has 23 chromosomes, the resulting embryo will have the normal total of 46 chromosomes. As the woman grows older, more and more of her eggs have either too few or too many chromosomes. This means that if fertilisation occurs, the embryo will also have too many or too few chromosomes. Most people are familiar with Down’s syndrome, a condition that occurs when the embryo has an extra chromosome 21. Most fetuses with too many or too few chromosomes do not end up pregnant at all or result in miscarriage. This explains the lower chance of pregnancy and higher chance of miscarriage in older women. In terms of the quantity of eggs, the ovarian reserve is gradually depleted over time. In contrast to the lack of any test to determine egg quality, we have medical tests to evaluate the ovarian reserve. These tests do not determine whether or not a woman can become pregnant, but they can determine if age-related ovarian changes have begun. Women with a poor ovarian reserve are less likely to become pregnant than women with a normal ovarian reserve. Indicatively some of the tests we use are measuring levels of antimyllary hormone (AMH), FSH etc.

Fertility evaluation at an advanced age

Infertility is usually diagnosed if a woman has not become pregnant after 1 year of unprotected sexual intercourse (i.e., no contraceptive measures are used). However, if she is 35 years or older, evaluation should begin after 6 months of unsuccessful attempts to conceive, and after 40 at 3 months. Also, if a couple has an obvious medical problem that affects their ability to conceive (e.g. sexual dysfunction, history of pelvic disease or previous ovarian surgery), they should begin evaluation immediately. Finally, women who have a pre-existing health problem, such as high blood pressure or diabetes, should ensure that they are periodically screened.

 

Fertility treatments at an advanced age

IVF may be an option in patients after 40, but success rates remain low and are even lower (<5%) after 42 years. On the other hand, egg donation, which involves the use of eggs donated by another woman who is under 30, is highly successful. The high success rate with egg donation confirms that age-related egg quality is the main barrier to pregnancy in older women. In an egg donation cycle, the woman who receives the free eggs is referred to as the ‘recipient’. The egg donor is given fertility drugs to stimulate and produce multiple eggs in her ovaries. At the same time, the recipient undergoes hormone therapy to prepare her uterus to receive the fertilised eggs (embryos).

 

Conclusion

Fertility decreases as women get older. However, the timing and rate of decline varies from woman to woman, but always starts well before menopause. Generally, fertility begins to decline in the early 30s and declines more rapidly after the age of 35. Women who have delayed pregnancy after the age of 35 should be given information about appropriate tests and available fertility treatments so that valuable time is not wasted. This can only be done through fertility specialists who set realistic goals and chances of success. Finally, prevention is always better than cure and this is why the issue of egg freezing at a younger age (<35 years) is more relevant than ever.

 

 

Bibliography

Fernandez AM et al. IVF in women aged 43 years and older: a 20-year experience. Reprod Biomed Online. 2021 Apr;42(4):768-773.

Drakopoulos P et al. Update on the management of poor ovarian response in IVF: the shift from Bologna criteria to the Poseidon concept. Ther Adv Reprod Health . 2020 Jul 31;14:2633494120941480

Cabry R et al. Management of infertility in women over 40. maturitas. 2014 May;78(1):17-21.

Chua SJ et al. Age-related natural fertility outcomes in women over 35 years: a systematic review and individual participant data meta-analysis.Hum Reprod. 2020 Aug 1;35(8):1808-1820