Reducing maternal mortality is a big challenge facing low-income nations. Some of the causes of maternal mortality have been studied, however, much less is known about differentials in pregnancy-related deaths among women of different age groups. This study used nationally representative data from demographic and health surveys (DHS) in Namibia, Kenya and Sierra Leone. A direct sisterhood method was used to estimate pregnancy-related deaths based on 7 years of recollection. Findings of the study reveal that death during the antenatal period was the commonest time of death in mothers aged 15–19, while death during delivery and two months after delivery were the leading causes of death for mothers aged 20–24. Pregnancy-related deaths were more prevalent among women with no schooling or primary education than their counterparts with secondary and higher education. Impact statement What is already known on this subject? Postpartum bleeding, malaria, anaemia, HIV/AIDS, unsafe abortion-related complications, obstructed labour, postpartum infections, high blood pressure during pregnancy and pre-existing conditions and cardiovascular disease are known causes of maternal mortality. However, much less is known about differentials in pregnancy-related deaths among women of different age groups. What do the results of this study add? Findings of the study revealed that death during pregnancy was the top pregnancy-related cause of death for mothers aged 15–19, while death during delivery and two months after delivery were the leading causes of death for mothers aged 20–24. Pregnancy-related deaths were more prevalent among women with no schooling or primary education than their counterparts with secondary and higher education What are the implications of these findings for clinical practice and/or further research? By knowing where the risk is highest as well as where the numbers of deaths are greatest, it may be possible to re-direct resources and fine-tune strategies for greater effectiveness in efforts to reduce maternal mortality.