How to understand from hormonal tests at what point is our fertility?

The existence of a woman is marked by two main stages concerning her reproductive life: the first menarche / menstruation and menopause. Between one and the other, however, there is a time interval that precedes menopause, called perimenopause, which represents a transition period characterized by hormonal fluctuations that have an influence on the well-being of the woman. In this period there are many women who are looking for the last chance for a new pregnancy and others who hope not to get pregnant . In this second case, the dancing cycle of this period can sometimes be a further source of anxiety.

While years ago women who reached the age of perimenopause had no further intentions of having other children, in recent years, thanks to the fact that a child is conceived, by choice, more and more later in the years, reproductive life and menopause merge as never before.

For example, while in 1990, only 9% of women had their first child after the age of 35, today, one in five women has their first child after the age of 35. The problem is that about a third of women over the age of 35 have fertility problems.

The main symptoms of perimenopause are the decline in fertility but also hormonal fluctuations.

The role of FSH

A girl is born with approximately 400,000 egg cells which remain dormant until puberty when very low FSH levels rise slightly to normal values ​​for an adult female. FSH (produced by the pituitary gland) is follicle stimulating hormone which stimulates the growth and development of ovarian follicles.

Each month it signals to mature a cluster of 10 – 20 egg cells. The cells around these egg cells begin producing estrogen, which in turn signals the pituitary gland to stop producing FSH. About a week after the start of menstruation, one of the maturing egg cells is selected as the dominant one for that month’s group and a week later is released in a process called ovulation.. After releasing the egg, the follicle becomes a corpus luteum and its cells begin producing progesterone and estrogen. Progesterone stabilizes the uterine lining and prepares it to receive a fertilized egg. If fertilization does not occur, the levels of progesterone and estrogen drop and menstruation begins and the cycle repeats.

Why does fertility decrease? FSH, AMH and Inhibin

Fertility begins to decline after age 35. But as early as 38, egg cells are shed from the ovaries at an even faster rate, and perimenopause symptoms may start to show. It is estimated that by age 40 a woman has 5,000 to 10,000 eggs left. These remaining eggs often respond less well to FSH and therefore ovulation does not occur (anovulatory cycles). The pituitary gland then continues to produce FSH because it does not receive “repsosta” (feedback) from estrogen and another hormone (inhibin B) whose job is to keep FSH levels low. As a result, FSH values ​​rise.

AMH, the anti-Müllerian hormone , is also another indicator of fertility. AMH values ​​above 1 ng/ml (nanograms per milliliter) indicate that you are still fertile. Values ​​of 0.3-0.6 ng/mL or less suggest low fertility and approaching menopause.

Most women who conceive easily have good AMH levels, and FSH levels below 10mIU/mL. FSH levels above 15 mIU/ml indicate impending perimenopause and levels above 30 to 40 mIU/ml are a confirmation of menopause. But FSH levels fluctuate from month to month, especially in perimenopause so a single value doesn’t have much meaning and the exam must be repeated.

If you are on birth control pills or estrogen or progesterone based drugs, these will lower your FSH levels. For this reason, you should stop taking it for about a week to get an accurate FSH measurement.

Of course, if you are in perimenopause and need contraception, continue to use non-hormonal ones (such as condoms or diaphragms) while checking your FSH levels.