Background Women and children bear a substantial burden of morbidity and mortality due to armed conflict. Life-saving maternal and child health (MCH) services are low-quality in most conflict-affected regions. Previous studies on armed conflict and MCH services have been mostly cross-sectional, and a causal relationship between armed conflict and MCH services utilisation cannot be inferred.Methods First, we constructed a utility equation for maternal health-seeking behaviour. Next, we extracted MCH data from the Multiple Indicator Cluster Survey led by the UNICEF. Armed conflict data were obtained from the Uppsala Conflict Data Programme; 55 683 women aged 15–49 from Chad, the Central African Republic, the Democratic Republic of Congo (DRC) and the Republic of Iraq were selected as participants. We fitted a difference-in-differences (DID) model, taking before or after the conflict started as an exposure variable to estimate the effects of armed conflict on maternal health-seeking behaviours.Results According to the results of the DID model, in the regional sample, armed conflict had a positive effect on tetanus vaccination (β=0.055, 95% CI 0.004 to 0.106, p