Your hormones

Your hormones are important indicators of your fertility, ovulation and general reproductive health. So it’s important to understand your hormones, and what they can indicate. Here we explain some of the common hormone related problems.

You may not know, but there are a number of key hormones that provide useful insights on your fertility health. Here we explain the main ones:

Anti-mullerian hormone – You are born with a certain number of eggs that decline over time. Your eggs live in little fluid-filled sacs called follicles that are in your ovaries. AMH is a hormone released by these follicles and therefore this hormone is a good reflection of the number of eggs you have, and a good indicator of your egg reserve and fertility potential.

Follicle stimulating hormone – This hormone is released by the pituitary gland in the brain. It’s job is to tell the ovary to develop a follicle (and by extension an egg) every month and also stimulates the follicles to produce oestrogen. If this hormone is within normal range, this is a good indicator that the pituitary gland and ovary are working normally and that you have a good number of eggs. This hormone rises when there are fewer eggs because the body needs to “work harder” to ovulate. This hormone may sometimes be low and this can occur for a number of reasons, and common causes include stress, low weight/BMI and excessive exercise.

Luteinizing hormone – This hormone is released by the pituitary gland in the brain, and it starts to rise in the first half of your cycle and peaks right before ovulation. This is the hormone you are measuring with the “pee sticks” so it’s helpful to help you understand if you are ovulating. We usually test for this hormone at the start of your cycle. If it is very high, it could be an indication that you may be approaching menopause or that you have polycystic ovarian syndrome. If it is very low it may be as a result of a number of conditions, which may include stress or low weight/BMI.

Prolactin – This hormone is produced in the pituitary gland, and is usually in perfect balance. If the pituitary is producing high levels of this hormone it can interfere with ovulation and lead to irregular cycles, and therefore is a useful test in this situation.  The pituitary may have a small tumour (often tiny and microscopic) which produces this hormone and often a simple medication is all that is needed to bring the levels back down to normal and allow ovulation to take place regularly.


The thyroid gland is the little engine that helps regulate all your hormones. It is butterfly-shaped and sits low on the front of your neck. It produces the hormone free thyroxine (T4) and if the levels are too high or too low it can have a significant impact on your general health and menstrual cycle.  It is particularly important in regulating metabolism and plays significant role in reproduction and pregnancy health. Both underactive and overactive thyroid are known to prevent ovulation and cause irregular cycles. So ensuring that you have a good thyroid function is important in the context of trying to get pregnant

The thyroid stimulating hormone (TSH) is produced by the pituitary gland in the brain and tells the thyroid to produce thyroxine. If it is too high it means the body is working hard to get the thyroid to produce an adequate amount of thyroxine and usually suggests that the thyroid is underactive. A simple daily tablet may need to be taken every day to bring the levels back into normal range. It is important that any thyroid condition is under control with medications before you fall pregnant as it can cause problems for a developing baby.

Hypothalamus problems – The hypothalamus is a small region in the brain which plays a crucial role in regulating all your hormones, including the fertility ones! It releases hormones that stimulate the pituitary gland (also in the brain) to release other hormones which act on your ovaries and thyroid gland (as well as other functions). The hypothalamus is sensitive to changes in the normal balance in your body. So, if you lose a lot of weight, are exercising too much, or if you are under a lot of stress, the hypothalamus may not release the hormones it needs to do to keep your body and fertility in check. This could be you if you have never had periods, or if they have stopped but you aren’t taking contraception.