Menopause and osteoporosis
BMJ Group Medical Reference
Most women go through the menopause at about the age of 50. When this happens, your ovaries stop making the hormone called oestrogen. Oestrogen helps to keep your bones strong. This is because it slows down the cells that break down old bone in your body.  Those cells are called osteoclasts.
When your body stops making oestrogen, your bone is broken down faster for between five years and eight years afterwards.  Then your body gets used to not having the oestrogen. The breakdown process slows down again.
This rapid breakdown of your bones happens whenever you have your menopause. So if your menopause comes early (before age 45), you can get osteoporosis at a young age.  And if it comes later than average, your bones stay strong for longer.
If you are very thin and have small bones, you are more likely to get osteoporosis right after you go through your menopause. 
Because oestrogen keeps your bones strong, your bones will get weaker if your body stops making oestrogen for any reason. This can happen if you have surgery to take out your ovaries. It can also happen if you stop having periods for six months or more (not including pregnancy or menopause). You can stop having periods if you eat too little or if you exercise too much. In these cases, your doctor may offer you drug treatment to replace the missing oestrogen.
Hormones are chemicals that are made in certain parts of the body. They travel through the bloodstream and have an effect on other parts of the body. For example, the female sex hormone oestrogen is made in a woman's ovaries. Oestrogen has many different effects on a woman's body. It makes the breasts grow at puberty and helps control periods. It is also needed to get pregnant.
When a woman stops having periods, it is called the menopause. This usually happens around the age of 50.
Women have two ovaries, one on each side of their womb. They are small glands that store eggs. Inside the ovaries are hundreds of thousands of pre-eggs, called follicles. Some of these grow into eggs.
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