The chemical messengers or hormones which make those muscles contract are called prostaglandins. These are the hormones doctors in London and Oxford have been investigating to find a treatment for the pain of the cramps.
In one way, a period which is getting rid of the unwanted lining of your womb is the start of the whole process and not the end of it. At the same time the prostaglandins are making those great muscles contract and do their work, the brain is sending out another set of hormones to start the cycle up again.
The particular part of the brain which is the control centre of the whole business is known as the hypothalamus. It controls the rate at which you grow and also the way your baby will develop inside your womb — among other things. It's a highly active control centre. As soon as it gets the message from your womb that your period is under way, it springs into action, sending off a new hormone to a small but very important gland nearby: the pituitary. This gland in its turn sends out another hormone, programmed to home in on your ovaries.
That tiny collection of microscopic cells that we call the ovary is capable of sending out really powerful hormones into our bloodstream, hormones which profoundly influence the way we behave, the way we feel and even the way we look. The first of these is oestrogen, and oestrogen, or rather the lack of it, is what some doctors think is the cause of the cramps.
As soon as the first message from the pituitary gland reaches your ovaries, all sorts of things start to happen. One of the unripe egg cells starts to grow and develop, gathering a collection of cells around it like a protective bubble. Gradually, during the next few days the bubble edges its way through all the other egg cells towards the surface of the ovary. At the same time, the ovaries are busy producing larger and larger quantities of oestrogen, which they release into the bloodstream and send on their way to the womb.
Your womb responds immediately by preparing itself for the start of a pregnancy, which is the object of the entire exercise. It starts to build up a completely new lining, ready for the egg to embed itself in; and just to make sure the door is open for the sperm to enter, oestrogen sees to it that the fluids in your vagina and around the neck of your womb thin out and become watery. Most of us aren't aware of any of this but there are other things happening as a result of the oestrogen flooding our systems and we are certainly aware of them. For as well as galvanizing our wombs into activity, oestrogen affects the skin, keeping it smooth and more elastic.
Before your period begins you may feel at a pretty low ebb, with lank unmanageable hair, pale skin, spots, fatigue, headaches. As soon as your period is under way, you begin to perk up again. Your energy returns, your skin clears and glows, your hair is manageable again, you feel your old sociable self. As many women say — life is back to normal. You feel you're starting again which is, of course, exactly what you are doing. And Nature has seen to it that you start at your most attractive and welcoming.
At some time about half-way through your cycle, the bubble of cells reaches the outside of your ovary. The egg cell inside the bubble is now ripe and ready for action. The bubble sends off a hormone message to your brain. All systems go! Back comes another chain of hormones from your brain to your pituitary gland and from your pituitary gland to your ovaries. Our bodies respond at once.
We produce a musky and very attractive scent (known as a pheromone). Some women are actually aware that they smell different at this particular time of the month; others don't notice it themselves, but husbands and boyfriends may do and will respond to it, even if they're not actually able to smell it. It's a subtle but very powerful turn-on. No wonder Napoleon, on his way back from a campaign wrote to Josephine: 'Home in three days. Don't wash.' At the very moment when you're at your most sexy, the bubble of cells inside you explodes, tossing the ripe egg straight into the waving tentacles that fringe the edges of your Fallopian tubes. It is wafted into one of the tubes where, if Nature has her way and you haven't done anything to thwart her intentions, millions of sperm may soon be swimming towards their target.
Meanwhile, in the ovary the exploded bubble is growing a yellow scar and that yellow scar is manufacturing yet another hormone which it sends out in spurts. This is the nesting hormone, progesterone, which will carry you into pregnancy. Quite a few doctors think that it's often a shortage of this hormone that causes the miseries. Like oestrogen, progesterone is a very powerful hormone and has a profound effect on the way our bodies work and the way we behave. It starts by making the Fallopian tubes contract, gently and rhythmically, so that the ripe egg is swept down towards the womb.
At the same time, it thickens the lining of the womb, into a spongy mass, full of blood vessels, ready for the fertilized egg to take root and grow. And just to make sure no unwanted sperm make a delayed entrance now they're no longer needed, it thickens the fluids in the vagina to block their passage. This thicker fluid, or discharge, is what many women see on their pants during the second half of the month.
Oestrogen makes us bloom; progesterone makes us motherly, because its job is to see that we are in the best possible condition to support a new life. It raises our body temperature so that we are warmer than usual; we put on weight; our breasts get bigger. It makes sure we have enough sugar circulating in our blood; and it helps to control the amount of salt, potassium and water we retain in our bodies.
Some women say this is the only time of the month when they really enjoy housework; others notice that this is the time when they wash the curtains or turn out the cupboards or start to Spring clean. But the month progresses and if the egg is not fertilized by a sperm, hormone messages relayed back to your brain from your womb make it clear that you are not pregnant.
One of the hormones responsible for seeing that these messages reach the brain is a substance called prolactin. Certain doctors have theorized that too much prolactin could be a cause of the aching miseries. The message is received in your brain. No pregnancy. So the whole cycle must begin all over again. Your ovaries cut back their production of oestrogen. The yellow scar stops making progesterone, and gradually fades away. The whole business is brought to a halt and it's the end of the month. We feel down, tired, finished. Our skin loses it bloom and our make-up won't take.
Our hair is a wreck and it's a waste of time having a set. Husbands or boyfriends get snarled at and pushed away. We don't feel like going out. We haven't got the energy for anything. In fact, some of us are downright antisocial. There's no doubt about it, another period is on its way.
