Pincus pills
MEDICINE JOHN ROWAN WILSON
One of the most important men ih the world died a few weeks ago. This was Gregory Pincus, . the man who developed the contra- ceptive pill. In the same way that Alexander Fleming has had far more influence on the lives 'of ordinary men than his contemporary Adolf Hitler; it is arguable that the work of Pincus will be of vastly greater significance for the future than that of Stalin or Mao Tse-tung. Pincus began trials with an oral con- traceptive • in 1956 in Puerto Rico. It had been known . since 1937 that the sex hormone pro- ge4terone• had the property of inhibiting the development of the ovum, but it was not until almost twenty years later that it was dis, covered how this could be applied to human contraception. The discovery was accidental during some experiments- on methods of treatment for infertility. It was .found that if the hormones oestrogen and progesterone were given" together, from the fifth to the twenty-- fifth day of the menstrual cyCle, fertility was abolished while causing very little discomfort or. disturbance of norinal physiology.
The first oral -contraceptive- to be used was norethynodrel (Enovici) and proved . remark-, ably successful. Since then, a number of other pills have been. developed and tested, differing in the exact substances used and their pro- portions. but all working on the same principle of a mixture of progestogen and oestrogen. The details of hoW this mixture .works have still not been completely elucidated. While the actual inhibition of Ovulation is due to the action of: the progestogen, the oestrogen seems to be necessary to prevent bleeding from the uterus during. the cycle'(known technically as 'break-through bleeding% The routine is shrink, and the companies Marketing the Pills. have exerted.ecinsiderable ingenuity in the way packs are presented, so as -.to ensure against errors or fOrgetfulness: One tablet is, taken. from day , S:(the fifth- daY after the 'first day of the menstrual" flow) daily, for twenty dayi. Then the tablets are stopped, Normally' bleeding starts within three or four days and . the first day of this withdrawal bleeding, is .regarded as day 1 of the next cycle. The method is extremely efficient and,, if carried out correctly, carries virtually .100 per cent. freedom from the risk of *.conception. Naturally, there haVe been questiOns asked about the advisability of taking sex hormones continuously in this way. All one can say abOut this. is that women have been taking them now for.over ten years with surprisingly little trouble. There is no evidence, for . instance, that later fertility is reduced by the taking of the tablets-.—if anything, it may possibly be increased. There is no evidence that there is any likelihood of producing cancer or foetal abnormalities. There are certain side-effects which -may occur. There may be some nausea, breast tenderness, headache or a feeling of tiredness: There may be 'break-through' bleed- ing during the cycle—this can often 'be con- trolled by giving a different type of"pill.
The most serious query which has been raised about oral contraceptiveS concerns the possibility of thrombosis in the veins of the leg. For 'years now, reports have been received of women developing such thromboses while they are on oral contraceptives. It has always been hard to assess the significance of these re- ports since a vast number of women now take oral contraceptives, and statistics show that of 1,000 •non-pregnant women of childbearing age, between two and three are likely to develop a thrombosis anyway. A series of investigations has been carried out in this country by the Committee on Safety of Drug., the College of General Practitioners, and the Medical Research Council, to try to get reliable figures on this question. The conclu- sion reached was that there probably is a slight increased risk of thrombosis from taking the Pill. However, according to the Medical Research Council, 'the risk is small and less :than that which arises from the ordinary pregnancy and delivery which these contracep- tives are intended to prevent.' It was not regarded as sufficient to justify restricting the use of the Pill, so long as it was only available on medical prescription.
The latest development in the oral contracep- tive field is the so-called 'sequential' pill. This .differs from the traditional kind in, that oestro- gen only is given early in the cycle and. a progestogen is added for the last few days. This is claimed by the manufacturers to be more physiological and to produce fewer side- effects. Medical opinion is still cautious about this formulation. While it inhibits ovulation, it lacks certain additional anti-fertility factors which characterise the . other method. The routine is more complex and, therefore, more liable to error. There is . a feeling that it may turn out to fall short. of the very high standard of reliability 'set by the older oral contracep- tives. However, it is still early to say if this will prove to be the case. Certainly, so long as women vary in their reactions to pills of different Composition, there is an obvious advantage in having as wide a range , of alternatives as possible.
Previous page
