Maternal health is important because it sets the scene, not only for survival and subsequent health of the infant, but also for the woman herself. The traditional measurement of maternal health is the maternal mortality ratio. Gross inequalities exist in the maternal mortality ratio between developed and developing countries, and the gap is not closing. The maternal mortality ratio in developed countries is about nine in 100 000 births; in sub-Saharan Africa maternal death is over 100 times more common, and the context is different from that seen in developed countries.1

In the linked study (doi:10.1136/bmj.b542), Knight and colleagues use the United Kingdom obstetric surveillance system (UKOSS) to assess another aspect of maternal health—severe maternal morbidity. The study shows that severe maternal morbidity is significantly more common in non-white women than in white women in the UK, particularly those in black African and Caribbean ethnic groups. It also shows that ethnicity is a marker for poor maternal outcomes, not just for an increased likelihood of maternal death.2

Studying severe maternal …