Can accurate data on birthweight be obtained from health interview surveys?

Abstract

Low birthweight continues to be a public health priority in many countries, because of its strong association with a child's subsequent risk of morbidity and mortality as well as the child's mental and physical development.1,2 This is especially true in developing countries, where th e prevalence of low birthweight is typically higher th an in industrialized countries and where social and environmental conditions associated with low b irth weight could potentially be improved through public health measures. Widespread use of th e incidence of low birthweight as a measure of the health of neonates, pregnant women, and women of reproductive age and as an indicator of the level of social and economic development of a population have increased the need for accurate information on birthweight.1,3 Unfortunately, however, suitable data on birthweight are lacking in most poor countries.

The major obstacle to obtainingbirthweig h t in fo rmatio n for a (nationally) representative sample in these populations is th a t a substantial fraction of newborns are n o t delivered in a hospital or clinic and would no t be included in whatever record systems exist. Restriction of analyses to those infants b om within th e formal health care system is likely to result in bias since, on average, women who deliver in hospitals and clinics are of higher socioeconomic status4-6 and are thus less likely to have low birthweight infants.

A partial solution to this problem has been the use of re tro spective questions in health interview surveys of a populationbased sample of mothers. For example, in surveys carried ou t in Asia, Latin America and Africa since 1990, the Demographic and Health Survey project has regularly included questions on birthweight for children born in the 5-year period prior to interview.3 Although this approach potentially includes children born outside the formal health care system, a serious drawback is th a t most of these children are probably no t weighed at the time of birth. Moreover, even those mothers who were told their infant's weight at the time of birth may no longer recall the correct figure.