Data collection
The data collection was performed during the summer of 2018, with a complementary search during the summer of 2019. The latter search revealed two additional children meeting the inclusion criteria, both born in the fall of 2016. The entries by doctors and physiotherapists working at the children’s hospital were reviewed using a predefined template (Appendix 1). All data related to age were corrected for prematurity if appropriate (gestational age <37 weeks). The first author performed most of the data collection, while the last author complemented it when needed. Any uncertainties were discussed until consensus was reached.