The dissertation, comprising a clinical intervention and three supporting studies, aimed to assess if it is possible to prevent nonsynostotic plagiocephaly while promoting safe infant sleeping practices. Five individuals were trained to assess cranial asymmetry and then reliability-tested; the interpreted results indicate substantial strength of rater-agreement. Intervention participants were allocated to group. Only intervention group nurses participated in the continuing education on plagiocephaly developed for nurses. A survey compared information intervention and control group parents received from nurses; intervention group parents (...) were significantly more aware of recommendations than the controls. Nurse education was evaluated by asking intervention and control group nurses and parents two open-ended questions; the intervention group reported new re-positioning strategies. The effect of the intervention on cranial shape was evaluated by assessing asymmetry at 2, 4, and 12 months (176 intervention group; 92 controls). It was nine times more common that cranial asymmetry at two months reversed by four months when parents were aware of written recommendations from their nurse (OR = 9.09 [0.02; 0.48], p = 0.004) when adjusted for group. An infant’s risk of asymmetry persisting until 12 months was significantly reduced in the intervention group (RR = 0.35 [0.13; 0.94], p = 0.03). Preventing brachycephaly was difficult. Conclusions: the assessors were considered reliable; educating nurses promoted the integration of new recommendations in practice; the intervention was associated with early reversal of nonsynostotic plagiocephaly. (shrink)