Why women have periods

By Professor Charles Kingsland, Consultant Gynaecologist & Specialist in Reproductive Medicine


I’ve been dealing with problems associated with periods professionally for over 30 years and socially, with a wife and daughters, for a lot longer. I suspect that over 50% of you reading this will be women. Most of you will have four or five days of bleeding from your vagina every month. Some periods will be heavy, some light, some regular and predictable, and some hardly ever. If you live to be over 50 and with a little bit of luck most of you will, your periods will stop all together. At this point you enter the strange and often mysterious world of the menopause.

To answer why women have periods, we need to delve back into ancient history and the development of the female as we know her today. Humans started walking on their back legs about 200,000 years ago, then came a relatively slow evolution over the next 199,900 years, for women at least.

Up until about three generations ago, which is a very short time in our evolutionary process, women had their first period around the age of 18. The average age of a woman having her first baby three generations ago, was 19. She then went onto have a string of pregnancies and spent the rest of her life having babies, breast feeding, miscarrying, stillbirths, getting chronically anaemic, contracting tuberculosis and dying. The average life expectancy for a woman three generations ago was 45.

Two things this poor creature never suffered from; firstly she never had a period because she was always pregnant or breastfeeding or losing a baby. Therefore, she never suffered from premenstrual tension either. Similarly, she never suffered the menopause, because she was dead.

Whilst at medical school, I spent three months learning about syphilis and tuberculosis, both mercifully rare diseases nowadays (although both are making a comeback). I had one 20 minute lecture on premenstrual tension and an even shorter one on the menopause. Both are very common diseases nowadays. The problem with them both is that they are modern, and because they occur exclusively in women, they are, in my humble opinion, poorly understood and even more poorly treated, although both, in their most severe form, can cause significant mortality and even death. This is the reason why, many Doctors know little about the said a aflictions and even less about how to treat them. These disorders tend to be, and in many cases still remain, ‘heartsink’ problems. But no more! The School of Fertility will see to that!

What changed a woman a lot more than anything else? What could be argued was the greatest medical breakthrough to affect planet earth, women especially in the past 1,000 years? As soon as women learnt how to control their fertility, their everyday lives changed immeasurably. By learning how to control their fertility, women were enrolled into that most exclusive of clubs, reserved until then for the male of the species; ‘The Freedom of Choice Club’.

Up until then, women tended to marry Mr First, not Mr Right. They could then be treated to the most horrendous abuse, but would have nowhere to go and no choice to do or be what they wanted. Free from the restrictions of continuous pregnancy, women were able to get an education, get a vote, compete with men, very successfully in some cases.

Now, just three generations later, such a short time in the history of the World, Women’s periods start at the age of 11 because they are so much healthier and better nourished. A woman in the developed western world can now expect to live well into her 9th decade.

I’ve heard my mother make a social comment on occasion and usually in response to some magazine article describing some new celebrity divorce, that divorce is so common nowadays and it wasn’t like that in her day and couples were still “happy”. For heaven’s sake mum, women had no choice! It was Mr First or nobody. Nowadays women realise that Mr First was not in fact Mr Right and so jettison Mr Wrong. And why not? What’s the point in spending your life in misery and in the knowledge that you are in the wrong relationship? I wonder how many women find Mr Right, first? That’s another study in itself, but might be worth reflecting on for a while. Anyway, unfortunately, there were consequences to this new found freedom.

First of all, with all of this freedom and power comes social responsibility, far more than when women were mere baby and nurturing machines. The result is that women are sometimes forced to delay their families.

Whether we like it or not, women’s biology has not kept pace with the massive changes that have taken place since birth control took a hold on society. Their eggs are older when they conceive with a result that they may not fertilise as well as they would have done when they were younger. The average age of a woman having her first child in the United Kingdom is now 31. With it comes an increase in the incidence of being unable to get pregnant; infertility.

There is however another price to pay for all of these massive changes; because women are no longer continuously pregnant, they are prone to some rather nasty diseases. For example endometriosis, a really unpleasant, but benign a affliction related to menstruation, along with premenstrual syndrome, an increase in the incidence of infertility, menopause, heavy periods, light periods, infrequent periods and painful periods. We also saw the birth, in the 20th Century of a specialty to deal with all of these new medical disorders. Yes ladies, the 20th Century saw the birth of Gynaecology. And that, in summary, is why women have periods.

Juliana Kassianos