Studies of long-term consequences of birth in breech presentation are sparse. Therefore, we conducted a cohort study linking birth registry data with data collected during evaluation for military service in 4,298 conscripts born between 1973 and 1976. The cognitive functions were measured with the Boerge Prien IQ test. A total of 164 conscripts were born in breech presentation and 70 (42.7%) of these were delivered after Caesarean section. The mean Boerge Prien test score was 43.2 among men born in cephalic presentation and 39.9 among those born in breech presentation for a difference of 3.3 (95% confidence interval = 1.8-4.7). The negative association between breech presentation and cognitive outcome persisted after stratifying by Caesarean section and after adjust ment for confounders. it also persisted when we restricted the analyses to term singleton pregnancies.
