When women notice that they are loosing excessive hair it is not usually in the form of a bald spot, but rather a diffuse loss over the whole scalp rather than the familiar thinning on top of the head and on the temples that is more common in men. This is despite the fact that the cause may be the same genetic. In other words you chose the wrong parents. If one of your parents suffers from hair loss of this type then your chances of doing the same are increased.
That being said many women experience hair loss for quite different reasons. Torsion alopecia for instance caused by pulling the hair roots because of a particular hair style or because of using rollers that are wound too tightly. The solution is simple stop doing it. Other female causes might be hormonal the end of a pregnancy, coming off the birth control pill or post menopausal. The first two are usually easily treated. You just need an extra dose of patience and after a while the body will reset its hormonal levels and your hair will regrow. This is a slow process however. Even in the best circumstances most of us only grow hair at the rate of ½ inch per month. Post menopausal hair loss is a rather different proposition and you need to think along the lines that a man with the same or similar problem might. There are treatments available which work for some, but they can be expensive and if discontinued your hair quantity will soon fall again. Also in some cases there are side effects to be contended with for the minority. A word of caution if you are of childbearing age some treatments are unsuitable for younger women as they can affect the unborn child.
Occasionally the cause is that of poor diet. Not just people who are starving, but those that are on extreme diets that are not based on a balanced eating regime may experience problems.
Just as in men the cause may be a general illness such as a thyroid deficiency or diabetes. I f you even suspect these consult a doctor. A probably rarer cause is an infected scalp, but that should be obvious and can be treated, either by your general practitioner or a dermatologist. Sometimes hair falls out in patches due to an auto immune condition. Again when seeking the best treatments for hair regrowth in women it is advisable to consult your doctor.
There are many shampoos, sprays, special combs etc on sale these days. Use them if you wish, but bear in mind that they are unlikely to work except as part of a wider treatment programme. Certain alopecia shampoos can unblock the pores from a a build up of sebum that can cause shrinking of the hair folicles, but often the damage to hair follicles is due to hormonal action. This can sometimes be successfully counteracted, but the earlier you start treatment the more likely you are to have real success. I f left too long the hair follicles will die and there is little that can be done except for surgical implants. But dont be discouraged. It may well be that your problem can be resolved either with treatment of with time.