Maternal mortality is a major global concern. The time period of maternal death in the USA after delivery is extended for up to 1 year after pregnancy, while according to the World Health Organization (WHO) that period is only within 42 days after pregnancy termination, these two different definitions of maternal deaths, in the USA and by the WHO, make it impossible to precisely compare maternal death ratios between the USA and the remainder of the world. With this in mind, the USA is the only high-income country where maternal mortality rates seem to have increased over the last decades. The cause of the differences between the USA and other countries could be the reporting mechanism and the differences in maternal mortality definitions between the Centers for Disease Control and Prevention (CDC) and the WHO definition. The causes of the increase in maternal mortality in USA are unknown but could include the higher age of women having their first child, and the increase in the obesity and opioid epidemic. In the USA, about one third of maternal deaths happen during pregnancy, about one third happen at delivery or in the week after, and about one third happen 1 week to 1 year postpartum, and about 60% of maternal deaths are potentially preventable.