Aetiology

This is unclear. The strongest association is with trauma and hypertension.

Other factors which have been associated with abruption are:

• past obstetric history of abruptio placentae
• pregnancy induced or essential hypertension - in up to 25% of patients with abruption
• multiple pregnancy
• increasing age
• high parity
• low socio-economic status
• renal infection
• drugs - smoking, cocaine
• uterine anomaly or tumour
• sudden uterine decompression - may endanger the second or subsequent children in multiple births
• short umbilical cord
• pressure from the enlarged uterus on the inferior vena cava

It has been suggested also that abruption may be caused by folate deficiency because:

• abruptio placentae is found more often in multiparous women with low socio-economic status
• there is an association between megaloblastic anaemia and abruption However:
• megaloblastic anaemia is common in Nigeria but abruption is not
• folate supplements are not protective