Placenta praevia describes a placenta lying wholly or partly in the lower uterine segment

Key clinical feature is painless bleeding after 24 weeks gestation

Epidemiology

• 5% will have low-lying placenta when scanned at 16-20 weeks gestation
• incidence at delivery is only 0.5%, therefore most placentas rise away from the cervix

Associated factors

• multiparity
• multiple pregnancy
• embryos are more likely to implant on a lower segment scar from previous caesarean section
• Previous TOP
• Assisted conception
• Advanced maternal age (>40)

PC

• shock in proportion to visible loss
• no pain
• small bleeds before large
• uterus not tender