Two groups of midwives were compared with regard to ability to detect small-for-gestational-age (SGA) babies using symphysis-fundus (S-F) measurements. The patients were all low-risk obstetric patients. In group A 2 midwives provided antenatal care to 97 patients; 14 delivered SGA babies, of which 12 were identified by S-F measurements (sensitivity 85.7%). In group B 15 midwives provided antenatal care to 126 patients, 12 delivered SGA babies, and 5 of these were identified (sensitivity 41.2%). It is considered that this difference was due to inter-observer variability. A plea is made for individualised antenatal care.