Which hormones regulate the ovarian reserve?

If after a year of regular, unprotected sex a couple has not conceived, it may be time to check that there are no fertility problems. Older women should consult a specialist sooner, after six months of trying for a baby.

Fertility testing and diagnosis usually starts by getting the couple’s medical history and a full physical examination of both partners. This allows the specialist to guide their diagnosis and determine the prospects for conception with the aid of fertility treatment.

One of the indicators for assessing women’s fertility is the ovarian reserve – the total number of oocytes present in the ovaries. The number and quality of eggs decreases with age; in other words, older women have a lower ovarian reserve and lower oocyte quality. However, factors other than age can also affect the ovarian reserve. And, in the case of younger woman, a low ovarian reserve need not affect oocyte quality.

Tests to determine the ovarian reserve

Blood tests are carried out to determine the ovarian reserve. This involves a hormone test to measure the following hormones:

• Follicle-stimulating hormone (FSH): this acts on the ovarian follicles by regulating the menstrual cycle and stimulating egg-cell production.
• Luteinizing hormone (LH): this controls follicle maturation. An increase in the level of this hormone acts as the signal for the ovary to release an egg-cell. The LH test allows ovulation to be assessed and can determine whether a woman has reached menopause.
• Estradiol: this is the most important of the oestrogens. The test for this hormone (sometimes also known as E2) enables the ovary function to be assessed. The test must be carried out between days 3-5 of the menstrual cycle.
• Anti-Müllerian hormone (AMH): this measures the ovarian reserve and the number of oocytes available in any given month. AMH is an important indicator of the potential effectiveness of treatment as it provides an assessment of ovarian response.

Interestingly, AMH acts independently of the menstrual cycle, unlike the other hormones mentioned whose values vary according to where a woman is in her menstrual cycle. In addition, AMH has a greater predictive value than the tests for FSH/LH/E2.