Objectives From the late 1980s ‘Back-to-Sleep’ (BTS) campaigns were run in most developed countries to increase awareness of the supine position's protective effect against sleep-related infant deaths. Once the media awareness-raising action associated with these campaigns ended, healthcare professionals' role became crucial. The goal of this paper is to determine if healthcare professionals' knowledge and parent advice consistent with evidence-based infant sleep recommendations have changed over the past 20 years.

Setting All studies investigating healthcare professionals' knowledge and/or advice to parents were included in a systematic review. The search was performed in PubMed and in MEDLINE, and 21 studies were identified.

Results The correctness of healthcare professionals' knowledge and parent advice about the supine sleeping position increased over the past 20 years. However, the percentage of those aware that parents should avoid putting their babies to sleep in a prone position is decreasing over time: from about 97% in the 1990s to about 90% at the end of the 2000s.

Conclusions The effectiveness of the BTS campaigns in publicising the benefits of the supine position is confirmed by this paper. More and more healthcare professionals know that it is the best position to reduce the risk of sleep-related deaths and they recommend it exclusively. However, the decrease in the knowledge about non-prone positions suggests that the campaigns may not have focused enough on the dangers of the prone position.