Shaken baby syndrome often occurs after shaking in response to crying bouts. We questioned whether the use of the educational materials from the Period of PURPLE Crying program would change maternal knowledge and behaviour related to shaking.
We performed a randomized controlled trial in which 1279 mothers received materials from the Period of PURPLE Crying program or control materials during a home visit by a nurse by 2 weeks after the birth of their child. At 5 weeks, the mothers completed a diary to record their behaviour and their infants' behaviour. Two months after giving birth, the mothers completed a telephone survey to assess their knowledge and behaviour.
The mean score (range 0–100 points) for knowledge about infant crying was greater among mothers who received the PURPLE materials (63.8 points) than among mothers who received the control materials (58.4 points) (difference 5.4 points, 95% confidence interval [CI] 4.1 to 6.5 points). The mean scores were similar for both groups for shaking knowledge and reported maternal responses to crying, inconsolable crying and self-talk responses. Compared with mothers who received control materials, mothers who received the PURPLE materials reported sharing information about walking away if frustrated more often (51.5% v. 38.5%, difference 13.0%, 95% CI 6.9% to 19.2%), the dangers of shaking (49.3% v. 36.4%, difference 12.9%, 95% CI 6.8% to 19.0%), and infant crying (67.6% v. 60.0%, difference 7.6%, 95% CI 1.7% to 13.5%). Walking away during inconsolable crying was significantly higher among mothers who received the PURPLE materials than among those who received control materials (0.067 v. 0.039 events per day, rate ratio 1.7, 95% CI 1.1 to 2.6).
The receipt of the Period of PURPLE Crying materials led to higher maternal scores for knowledge about infant crying and for some behaviours considered to be important for the prevention of shaking. (ClinicalTrials.gov trial register no. NCT00175422.)