BACKGROUND: Survival of mothers and newborns depends on life-saving interventions reaching those in need. Recent evidence suggests that indicators of contact with health services are poor proxies for measures of coverage of life saving care and attention has shifted towards the quality of care provided during contacts. METHODS AND FINDINGS: Regression analysis using data from representative cluster-based household surveys and surveys of the frontline health workers and primary health facilities in four regions of Ethiopia in 2012 and 2015 was used to explore associations between increased numbers of contacts or improvements in quality and any change in the coverage of interventions (intervention coverage). In pregnancy, in multiple regression, an increase in the quality indicator 'focused ANC behaviours' was associated with a change in both the coverage of iron supplementation and syphilis prevention ((regression coefficients (95% CI)) 0·06 (0·01, 0·11); 0·07 (0·04, 0·10)). This equates to a 0.6% increase in the proportion of women taking iron supplementation and a 0.7% in women receiving syphilis prevention for a 10% increase in the quality indicator 'focused ANC behaviours'. At delivery, in multiple regression the quality indicator 'availability of uterotonic supplies amongst birth attendants' was associated with improved coverage of prophylactic uterotonics (0·72 (0·50, 0·94)). No evidence of any relationships between contacts, quality and intervention coverage were observed within the early postnatal period. CONCLUSIONS: Increases in both contacts and in quality of care are needed to increase the coverage of life saving interventions. For interventions that need to be delivered at multiple visits, such as antenatal vaccination, increasing the number of contacts had the strongest association with coverage. For those relying on a single point of contact, such as those delivered at birth, we found strong evidence to support current commitments to invest in both input and process quality.