The report by Sunyer et al 1 of an association between malaria parasites in umbilical cord blood and wheezing at 4 years of age is of considerable interest. Their interpretation of these findings is related to an association with unspecified intrauterine events. A further explanation is that babies with cord parasitaemia were more likely to be born preterm. The importance of preterm delivery in predisposing to recurrent cough and wheeze in children (5–11 years) living in a non-malarious area has been reported, and premature babies of asthmatic mothers were found to be at very high risk of childhood symptoms.2 Redd et al have also observed, in a large cohort study from Malawi, that malaria cord parasitaemia was significantly associated with preterm delivery (odds ratio (OR) 2.51, 95% confidence interval 1.45 to 4.18), intrauterine growth retardation (OR 2.49, 95% CI 1.47 to 4.06), and maternal HIV infection (OR 2.87, 95% CI 1.74 to 4.60).3 These factors may confound the association of cord parasitaemia with wheezing reported by Sunyer et al. Malaria during pregnancy is well described as a major cause of prematurity and growth retardation in babies born in malarious areas,4 and it would be helpful to know the birth status (preterm, low birth weight, or growth retarded) of the children from the Tanzanian study. In view of the high attributable risk of malaria related low birth weight in developing countries, it will be important to ascertain its possible influence on the risk of asthma during childhood.