The connection between the amount of antenatal care and pregnancy outcome was studied using the 1987 Finnish Medical Birth Registry. A total of 57,108 women were included in the analysis. The timing of initiation of antenatal care and the relative number of antenatal visits (adjusted by gestation length), were used as measures of amount of antenatal care. Nine outcome variables measuring infant health and interventions were studied. Logistic regression was used to adjust for differences in maternal background characteristics. Women beginning antenatal care after the 16th week of gestation had the poorest outcome. Early attending multiparous women had a higher risk of low birthweight, premature infants, caesarean section and instrumental delivery than did those with average timing of their first attendance. For primigravidas, the increased risk was of prematurity only. A U-shaped curve was found for most of the outcome variables in regard to relative number of visits. The women with many visits had the poorest outcome, and also the highest rates of caesarean section and induction of labour. One reason for the unexpectedly high risks for early attenders may be connected with the content of antenatal care. In Finland, it might be possible to reduce the total number of antenatal visits without having any negative effect on infant health.