Oestrogen is the primary sex hormone. It is actually a whole class of different hormones, the main three being oestradiol, oestrone (the main hormone) and oestriol. Together these three hormones control female sexual production. An Imbalance of oestrogen can lead to a number of health problems including your periods stopping, infertility and other conditions like osteoporosis where girls develop thinning and weakening of their bones.
Oestrogen is a girly hormone and can be blamed for the girly traits you may have. It controls female sexual development (all the things that make you both different and alluring to guys) and in puberty oestrogen is responsible for:
After puberty oestrogen controls your menstrual cycle (your periods) along with three other hormones: FSH, LH and Progesterone. Oestrogen stops FSH being produced which means only one egg matures in a cycle and it stimulates the release of the hormone LH which tells the ovary to release the egg. It also causes the lining of the uterus to thicken in preparation for a fertilized egg. If a woman gets pregnant her oestrogen levels will dramatically increase. Oestrogen is also found in oral contraceptives (your birth control pill).
Oestrogen also plays a really important role in bone health and a lack of oestrogen may lead to osteoporosis (brittle, weak bones) which can lead to bone fractures and breaks.
It is unsure what the exact effect of oestrogen is on mood in women. Some experts suggest that it is not necessarily one hormone in particular that causes the irritability so often connected with women and their “hormones” but, more likely, the change of hormones and their levels that causes the mood disturbances. As such oestrogen may not be the main culprit as it actually promotes the production of serotonin which is a mood lifting hormone.
There are a number of things that can lead to your oestrogen levels dropping below or rising above normal. Low oestrogen levels are commonly found approaching and following the menopause (usually in women 50) or in those with a low body fat and when someone’s been exercising / training consistently hard. Girls with polycystic ovaries and with problems with their pituitary gland can also have low levels. Elite athletes, dancers and those with eating disorders may have body fat so low that their oestrogen levels drop causing a number of potentially adverse side effects:
On the other hand, those who are overweight, are on certain medications, have high blood pressure or diabetes can sometimes have increased levels of oestrogen.