- To investigate pregnancy and labour outcomes in grand and great grand multiparous women. A retrospective population-based study was conducted between the years 1988 and 2007. Parturients were classified into three groups: multiparous; 2-5 deliveries, grand multiparous; 6-9 deliveries, and great grand multiparous; 10+ deliveries. Stratified analyses included multiple logistic regression models. A significant linear association was found between parity and adverse maternal and perinatal outcomes such as malpresentation, labour dystocia, caesarean delivery, postpartum haemorrhage, maternal anaemia (HB<10), congenital malformations and perinatal mortality. Using multivariable logistic regression models, grand multiparity was found an independent risk factor for labour dystocia, first stage (OR=1.5, P<0.001), and perinatal mortality (OR=2.0, P<0.001). Great grand multiparity was found an independent risk factor for labour dystocia, first stage (OR=2.6, P<0.001), labour dystocia, second stage (OR=2.1, P<0.001), and perinatal mortality (OR=2.5, P<0.001). Women with high birth order are at increased risk for adverse obstetric outcomes. The risk is higher for great grand multiparous women compared to grand multiparous women. Grand and great grand multiparity are independent risk factors for labour dystocia and perinatal mortality.