The course and outcome of 142 pregnancies in 146 patients operated between 1970 and 1975 by the Harrington method for idiopathic scoliosis were studied to determine the effects of scoliosis on pregnancy and childbirth and the effects of pregnancy on the remaining fused and unfused scoliotic curvatures. Occurrence of and sick leave due to low back pain during pregnancy was determined. The patients, all originally treated at the Orthopaedic Hospital of the Invalid Foundation (Orton) in Helsinki, Finland, were invited to a clinical and radiological re-examination on average 19 years following surgery. The results show that pregnancy does not significantly increase fused scoliotic curvatures nor the remaining unfused curvatures. A somewhat higher proportion of children (23%) were delivered by cesarean section than in the general population (15%; P < 0.01), but this result should only be taken as suggestive. Rates of complications of pregnancy and in labor did not differ from those in the background population. The offspring were healthy. Low back pain during pregnancy occurred in about 40% of our patients, but was severe enough to cause sick leave only in 11% of the pregnancies.