Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 70% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis. In those with infection, labour frequently ensues and survival depends on gestational age at amniorrhexis. In those without infection the pregnancy continues and death is then dependent on the development of pulmonary hypoplasia (PH).