In its commonest and most effective form the Pill contains the synthetically produced female hormones, oestrogen and progesterone. Because these two are combined in one pill it is called the ‘combined Pill’. The hormones these Pills contain are very similar to the natural ones produced by a woman’s body but are different enough to allow absorption from the stomach and intestines. Natural hormones would not be absorbed if taken by mouth. The Pill’s constituents are, after absorption, so similar to the natural hormones that they influence chemo-receptors (specialised monitors of blood hormone levels) at the base of the brain in the same way as natural hormones. If they were not identical or nearly so they would not work because

chemo-receptors are highly specific. Because of this it is not quite right to think of them as totally alien chemicals, which is how they are sometimes represented. The reason the Pill works so well is that it copies Nature. Its effect is to convince the pituitary gland that a pregnancy has already occurred and in this state the pituitary suppresses the release of the hormones which normally make the ovaries release an egg each month. It is a form of false pregnancy.

It sometimes happens that whilst a woman is on the Pill an egg is produced, but conception still does not occur because one effect of the progesterone in the Pill is to make the mucus in the passage through the cervix so thick that no sperms can penetrate it. A further effect of the combined Pill is to prevent the development of the lining of the uterus, the endometrium, so that even if conception were to occur the embryo could not implant and grow there. Although there have been tremendous advances in oral contraception some improvement is still possible.

There are 24 different brands of the Pill available and the principal basis on which one is chosen rather than another is to administer the lowest doses of hormones that suit the particular needs of the woman. In some cases the medical and family history may make the Pill an unsuitable choice. Starting and administration instructions vary. The phased Pills, in which the ratio of oestrogen to progesterone varies throughout the pack so as better to imitate what happens in the natural cycle, are different from the 21 tablet formulations. Instructions about what to do if a pill is taken late or missed, or if it is desired to postpone a period, also vary so instructions for a particular Pill must be followed carefully.

What seems to be a period for the woman on the Pill is not one in fact. It is a withdrawal bleed due to the supply of hormones being stopped.

The Pill’s constituents are broken down by the body over twenty-four to thirty-six hours and are excreted via the urine and stools. Some women metabolise the Pill more rapidly and so need higher doses. Others who are on certain drugs such as some anti-tubercular, anti-epileptic, or anti-fungal drugs and some antibiotics also metabolise the Pill more rapidly, as may vegetarians. This could mean that they need a higher-dose Pill to be safe. If these women are on a

normal-dose Pill, it, so to speak, ‘runs out’ before the next one is due. Women who, perhaps for the psychological reasons mentioned earlier, ‘forget’ the Pill or who are very late taking it are also exposed to the Pill running out. In all of these cases the sign to go by is the spotting of blood or even a full withdrawal bleed. If a pill has only been taken, say, six hours late, spotting is not inevitable, but if it does occur it happens two or three days later. In other words it is a ‘mini’ withdrawal bleed. The reason why a full bleed does not occur as a rule is that the woman continues to take the Pill. The correct reaction to repeated spotting or withdrawal bleeding at unexpected times, provided it is not caused by interference from other drugs, is not to change the Pill you are on, as many doctors and clinics suggest, but rather to be scrupulous in taking it within, say, an hour of when it is due.

The Pill is a very safe and efficient contraceptive but problems can and do sometimes occur. Problems mostly arise in those who are found on psychosexual investigation to have unconscious difficulties about accepting their sexuality, as we mentioned earlier. These should be cleared up before a change in method is seriously considered, simply because all other methods are less efficient. Depression, irritability, and bad dreams can be due to unconscious self-detestation for Pill-taking and depression often results in a loss of sex drive, a failure to have orgasms, and

over-eating, leading to the marked weight gain sometimes reported on the Pill. This is not to say that all Pill symptoms are emotional or psychological but many are and can be prevented or cured by psychosexual counselling alone. It is interesting that in studies in which women were given a dummy tablet yet were told it was the Pill, the women had Pill-like symptoms which went on until they stopped taking the tablets!

Medically the Pill has both advantages and disadvantages. It is thought that statistically the former outweigh the latter. Although it can (rarely) lead to blood clots and may or may not (the evidence is conflicting) increase the chance of breast cancer and cancer of the cervix, it reduces benign breast disease, produces a two to three fold reduction in the chance of having an ovarian or endometrial cancer and, in older ex-Pill takers, protects against osteoporosis. Its lesser benefits, such as reducing pains associated with menstruation thereby, perhaps, reducing the consumption of pain relievers which can be harmful in themselves, are very considerable.

Obviously careful medical supervision is advisable because this ensures correct usage, is reassuring for the woman, provides an opportunity to disentangle psychosexual factors which may greatly benefit the woman and her partner in other ways, and provides a basis for regular health checks including cervical smears. Most of the things which are found to be wrong when doctors carry out routine Pill checks are nothing to do with the oral contraceptive.

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