Introduction Lack of timely recognition, referral and appropriate treatment of women who are developing a critical illness during or after pregnancy feature prominently in national and international reports. One systems solution to help overcome this problem is the modified obstetric early warning scoring system (MEOWS), which allows regular tracking of observations, providing early signs of impending critical illness to enable earlier response and rescue (CEMACE 2011). There is little evidence of its effectiveness; this research focuses on this tool ‘in-action’ to understand its role in managing safety.

Methods Data collection involved over 120 hours of ethnographic observations of labour ward activity and multidisciplinary team meetings, documentary review and over 40 interviews with stakeholders, obstetric and midwifery staff and managers from two UK hospitals over seven months.

Results The MEOWS chart enabled co-ordination and structuring of information about vital signs, and the trigger prompts helped shape perceptions of deterioration and clarify actions. However, there was resistance to the imposition of the tool for all women given the majority of normal births and the relatively rare event of severe maternal morbidity. Partial adoption of the MEOWS in-practice meant that the tool was limited by geographic, temporal and spatial boundaries. Implementation of the MEOWS lacked integration within a wider system approach to managing critically ill women.

Conclusion Translation of the EWS from acute care to maternity is a complex process. Future strategies need be embedded within a robust system which includes both detection strategies and a standardised response component to managing critically unwell women.