Side effects of steroid contraception during lactation are discussed and followed by a review of the relevant literature. It appears that oestrogen has an inhibiting effect on lactation performance, but progestogen alone does not. Most of the undesirable systemic side effects of oral contraceptives on the mother are connected with the relative excess or deficiency of the oestrogen and/or the progestogen component. It is likely that a low oestrogen content preparation causes no dangerous side effects. There are few data about the appearance of contraceptive steroids in breast milk. Probably only a small proportion of the steroids are excreted into the milk. Any adverse effects, on the infant, such as slow weight gain, neonatal breast hypertrophy and breast milk jaundice, are dependent on the two preceding factors. It is doubtful whether the small amount of contraceptive steroids contained in modern pills exert any influence on the fetus. Although further examinations are necessary, the low dosage of progestogen and oestrogen combined contraceptives given at fully established lactation under close control seems to be advantageous to both mothers and their infants.

The realization that steroidal contraceptives administered immediately after delivery to lactating women may be excreted into milk, and adversely affect the neonate, is a cause for concern. Most investigations on hormonal contraceptives have dealt with the efficacy of ovulation suppression, and systemic side effects, but little is known about the appearance of steroids or their metabolites in milk. Apart from the immediate side effects on the neonate, unforeseen long-term consequences require special consideration. Until research provides us with more information, women should use breast-feeding and IUDs instead of steroidal contraceptives during the first trimester post-partum.

I have not encountered any evidence, anecdotal or otherwise, that lactation is influenced by male methods of contraception including coitus interruptus, or by female barrier or chemical (other than hormonal) methods.

The use of intrauterine contraceptive devices (IUDs) has been claimed to enhance lactation. In Chile, Gomez-Rogers et al. (1967) studied 81 women fitted with IUDs at an average of 50 days post-partum, in whom the lactation half-life (time when 50% had stopped nursing) was 7 months 21 days. In 150 controls, the lactation half-life was 4 months 21 days, the difference being statistically significant.

We have assumed from the temperate world that the cow is essential; we need to question this assumption. The answers will vary considerably from country to country. I suggest that there are two sorts of country: first, countries such as Bangladesh and Nigeria, where no possibility of a milk industry exists. Therefore, if milk is used it has to be imported.

It is a presumption for us in the West to say so, but I suggest that the sensible action is to reduce progressively milk imports and to look at substitution of other materials. A certain amount of work has been done on soya milk; however this may not be suitable as it may be difficult to produce at village level. There are many other possibilities; for example, if a child with a chronic diarrhoeal problem is admitted to a hospital where I work it is fed on a mixture of chicken, glucose and oil. This sort of mixture could be made up in a village. We need to look at such possible alternatives for infant feeding.

We have heard a lot about the promotion of sales of baby food, but we have never analysed the population's readiness to accept such foods, and how that acceptance comes about. Nor have we analysed the role of the doctors or the health professionals. What is it or what should it be ?

About a year ago we carried out a study in London on the intention to breast-feed and the success of mothers in breast-feeding (Liebrich & Morley, 1976), at the same time analysing the attitudes of the staff attending these mothers, who should have helped the latter in their breast-feeding. Table 1 shows a trend in the answers given by women who intend to breast-feed disagreeing with such statements as ‘Nowadays it is no longer necessary to put up with the mess of breast-feeding when easily prepared milks are available’ and agreement (among the same group of mothers) with such statements as: ‘Breast milk is the best food for a baby under four months’.

I should like to discuss both the demographic and public health implications of the matters which have arisen at this meeting.

There are clearly some areas of consensus: we all agree that lactation is of fundamental importance, and that the birth interval is important, both for the health of the mother and child and with regard to fertility. Obviously, the longer the birth interval, the fewer births a woman will have during her reproductive life. A number of schemes were presented yesterday to show that in traditional societies with very long birth intervals there will be a reduced total fertility.

It is surprising that although the IPPF is 27 years old it has never previously had a meeting on this topic. On rational grounds, it is one of the first subjects at which it might have looked because many of the data we have discussed were available long ago. I remember reading about a Western doctor in Asia who saw the familiar scene of a mother with a young baby being suckled from one breast and an older child from the other breast but, in this case, the older one was also smoking a cigarette between sucks! Perhaps we need some kind of startling image like that to make us look closely at the role of lactation in fertility regulation.