Objective To clarify the problems related to maternal deaths in Japan, including the diseases themselves, causes, treatments and the hospital or regional systems.

Design Descriptive study.

Setting Maternal death registration system established by the Japan Association of Obstetricians and Gynecologists (JAOG).

Participants Women who died during pregnancy or within a year after delivery, from 2010 to 2014, throughout Japan (N=213).

Main outcome measures The preventability and problems in each maternal death.

Results Maternal deaths were frequently caused by obstetric haemorrhage (23%), brain disease (16%), amniotic fluid embolism (12%), cardiovascular disease (8%) and pulmonary disease (8%). The Committee considered that it was impossible to prevent death in 51% of the cases, whereas they considered prevention in 26%, 15% and 7% of the cases to be slightly, moderately and highly possible, respectively. It was difficult to prevent maternal deaths due to amniotic fluid embolism and brain disease. In contrast, half of the deaths due to obstetric haemorrhage were considered preventable, because the peak duration between the initial symptoms and initial cardiopulmonary arrest was 1–3 h.

Conclusions A range of measures, including individual education and the construction of good relationships among regional hospitals, should be established in the near future, to improve primary care for patients with maternal haemorrhage and to save the lives of mothers in Japan.