Maternal nutrition and perinatal survival.

This review addresses the relationship between maternal nutrition and the survival of the foetus and infant. This survey was undertaken because wide-scale programmes on maternal feeding are in process, based, not on a critical synthesis of currently-available empirical research, but on a series of nested and, at times, weakly supported, assumptions. It is concluded that: (i) maternal weight and weight gain are remarkably resistant to either dietary advice or supplementation; (ii) nutritionally-induced increased birth-weight does not universally increase the chance of survival of the offspring, since pre-pregnancy weight, at least in affluent, industrialized societies-while associated with increased birth-weight-is also associated with higher perinatal mortality; (iii) while dietary supplements during pregnancy do have a modest effect on birth-weight, in contrast to a large effect in famine or near-famine conditions, this is not mediated by maternal energy deposition; and (iv) declining peripheral fat stores in late pregnancy are associated with accelerated foetal growth, and improved nutrition can lead to lower fat stores. Rather, the component of maternal weight gain associated with accelerated foetal growth is water, and, presumably, plasma volume. In the few studies, large and thorough enough to adequately address the issues, maternal feeding--both in famine and non-famine conditions--has led to lower perinatal, primarily foetal, mortality; the mechanisms are not likely to have been due only to the acceleration of foetal growth. It is concluded that there is currently an inadequate base of secure knowledge to foster improvement in the health and nutrition of poor mothers and children. The public and policy-makers alike must be informed that greater knowledge relating maternal nutrition to perinatal outcome is urgently needed to create sound health advice and to mount effective programmes.