Advising patients on the risks of oral contraception.

ACCORDING to Peel and Potts (1969) "The woman who begins taking oral contra¬ ceptives has a greater likelihood of being alive one year later than has her sister who chooses to have a baby or to use some less effective method of contraception." This statement is fairly well known because many oral contraceptive salesmen have used it (and an accompanying table) as a sales aid. The implication is that oral contraceptives are safe. Indeed the safety is now even more assured because of the move to lower oestrogen dose products. This move was brought about by the researches of Inman et al. (1970) and the action of the Committee on Safety of Drugs. Inman et al. demonstrated that the risk of thrombo-embolic disease for oral contra¬ ceptive users was related to the amount of oestrogen in the contraceptive. At the press conference called by the Rt Hon Richard Crossman following the publication of Inman et al. and the statement by the Committee, two points were made: (1) The risk of fatality had been reduced from 3 per 100,000 to 3 per 200,000; (2) "A woman would have to take the pill for 16 years in order to equal the risk of one single pregnancy" (according to Sir G. Godber, Chief Medical Officer, Department of Health). All this seems reassuring.oral contraceptives are safe. Unfortunately, as we shall attempt to show such a conclusion is not valid for the practitioner faced with offering advice to his patients. Let us return to the Peel and Potts' statement and the method reached to arrive at such a conclusion. The method is fairly simple and the stages are as follows. First, consider some theoretical size of population (merely to give some iife' to the statistics) and assume that the population all use one contraceptive method. Second, multiply the population figure by the contraceptive failure rate. Third, given a figure from step two, i.e., number of pregnancies, multiply this by the risk of death in pregnancy. This gives us the number of deaths resulting from pregnancy. Fourth, multiply the original population figure by the risk of death figure. Finally, add the figures of steps three and four to obtain the total death rate for the given contraceptive method. The above procedure may be used for any contraceptive method or even no contraceptive. The resulting figures allow us to compare the risks of various methods. An extract of the Peel and Potts' table is presented.