APH = bleeding from the genital tract after 24+0 weeks
Often underestimated - revealed loss may not be indicative of total blood loss - blood can collect between the uterus and placenta in placental abruption
Important red flag causes:
Placenta praevia
Placental abruption
Uterine rupture
Vasa praevia
Causes to consider:
Placenta praevia
Placental abruption
Local causes - cervical ectropion, cervicitis, polyps, malignancy