Fig. 4From: Trends, causes and solutions of maternal mortality in Jinan, China: the epidemiology of the MMR in 1991–2020Differences of the MMR due to direct and indirect obstetric causes in different periods. Differences were analyzed by Chi-square test and significant differences were observed in 1991–2000 (P = 0.001),2011–2010(P = 0.001) and in 2011–2020 (P = 0.012)Back to article page