Intervention group
From 17–22 gestational weeks, the intervention group was offered supervised group exercise twice a week for 12 weeks at the training centre at the Rigshospitalet Clinic of Occupational Therapy and Physiotherapy. The exercise intervention was developed and supervised by four physiotherapists from Rigshospitalet in accordance with the Danish national recommendations for exercise during pregnancy (21). The intervention is described in details in the study protocol (19).
To increase compliance, a weekly supportive email was sent to the participants in the intervention group and the women’s general practitioners were informed about the intervention. Participation was recorded by the physiotherapists at each session as a standard procedure.