Between 2001 and 2003, the pattern of antecedent causes of death remained fairly stable (Figure 18, Table 125). About 30 per cent of perinatal deaths were unexplained. The next most common obstetric antecedents were fetal abnormalities followed by spontaneous preterm birth, specific perinatal conditions (such as twin-to-twin transfusion) and antepartum haemorrhage.