Hormones
Oestrogen
Oestrogen is the principal female sex hormone produced by the ovaries. Amongst other things, oestrogen is vital for the growth of eggs and for the reproductive process. Oestrogen is not just one hormone but three:
- Oestrodiol is the main type of oestrogen and the most potent. It plays a major role during puberty. It both enlarges the womb and thickens its lining (endometrium). It is also used by the ovaries to signal to the hypothalamus and pituitary gland that the egg follicles have been stimulated and FSH (Follicle Stimulating Hormone) production slows down.
- Oestrone is produced by the adrenal glands and oestrogen manufacturing fat cells. This type of oestrogen continues to be produced after the menopause.
- Oestriol is converted from oestrodiol and oestrone by the liver.
Progesterone
Progesterone is a female hormone produced by the ovaries. One of its many functions is to help to maintain pregnancy. It is secreted by the corpus luteum during the second half of the menstrual cycle and signals to the uterus that an egg has been released.
Follicle Stimulating Hormone
Follicle Stimulating Hormone (FSH) is released by the pituitary gland which is carried to the ovaries to stimulate the follicles. As FSH levels rise, some of the eggs respond with low levels of oestrodiol. By doing so the ovaries communicate back to the pituitary gland that the egg follicles have been stimulated and FSH production slows down.
However, when the supply of egg follicles is low and they are unresponsive to stimulation, the pituitary gland tries to compensate by producing more FSH every month. The overall levels of FSH rise.
Premature ovarian failure is suspected if you are under 40, have had no periods for some time and your FSH level is over 30 iu/l.
A single FSH level test with no menopausal symptoms is not conclusive as FHS levels can fluctuate. High levels may indicate resistant ovary syndrome rather than premature ovarian failure.
Lutenizing Hormone
Lutenizing Hormone (LH) is released by the pituitary gland into the bloodstream and triggers ovulation i.e. the active follicle bursts and releases the egg. The ruptured follicle sac called the corpus luteum (body of yellow) turns yellow and, due to the action of the LH produces progesterone.
Testosterone
Testosterone is also produced by the ovaries and a woman’s levels drop by 20% after a ‘natural’ menopause and by 50% after a surgical menopause. It is thought that low testosterone levels result in poor libido and lack of energy.