The possible influence of the expectant mother's knowledge of childbirth on the outcome and experience of pregnancy and labour was investigated by means of a postpartum questionnaire in 1238 primiparae The mothers were divided into two groups according to their basic childbirth knowledge At birth, the conditions of newborns were equal in both groups when judged by Apgar scores The low knowledge level group had small-for-gestational-age babies more frequently and these babies were also treated in the paediatric ward more frequently than those in the high knowledge group The latter group was significantly more critical towards the staff of the delivery room and the postnatal ward, the fathers of this group were also present at delivery significantly more frequently The low knowledge level group was significantly more unwilling to have another pregnancy in the near future or ever The results indicate that low childbirth knowledge is associated with a poorer pregnancy outcome It is a message to antenatal care staff of the need for support, supplementary education and careful obstetric surveillance Low childbirth knowledge may imply a set of problems, including those in interparental relationship, socio-economic situation and need for close surveillance and improved education