B A C K G R O U N D
Placental abruption and placenta praevia are the two major causes
of antepartum haemorrhage - vaginal bleeding during the second
half of pregnancy. Placenta praevia is a placenta that is situated unusually
low in the uterus, and is discussed in a separate Cochrane
review (Neilson 2003). Placental abruption is the premature separation
of a normally sited placenta, from its attachment to the
uterus. Placental abruption is a recognised cause of maternal death
(Lewis 1998), especially in resource-poor settings in low-income
countries (Prual 2000), and of death of the baby - either because of
sudden hypoxia or because of premature delivery. Abruption has
been estimated to occur in 6.5 pregnancies per 1000 births, with
an associated perinatal mortality rate of 119 per 1000 (compared
to 8.2 per 1000 overall in the reference US population) (Ananth
2001a). Placental abruption is twice as common in twin, than singleton,
pregnancies (Ananth 2001b).