APH

Causes of APH include:

• Placenta praevia
• Placental abruption
• Vasa praevia
• Bleeding from cervical or vaginal lesions e.g. cervicitis, trauma, infections, vulgovaginal varicosities or genital tumours

Or the cause may be unknown.

PPH

The causes of PPH are denoted by the four Ts:

• Tone - uterine atony is the commonest cause of PPH
• Trauma - cervix, vagina, perineum, anus, rectum, broad ligament, bladder, uterine rupture or inversion
• Tissue - retained placenta
• Thrombin - development of clotting abnormality especially in conditions such as massive haemorrhage, pre-eclampsia, fetal death, amniotic fluid embolism or sepsis

Tone and trauma account for 80-90% of PPH.