Antepartum haemorrhage: differential by presentation

What it is

Antepartum hemorrhage is bleeding after 24 weeks of gestation. The causes are idiopathic bleeding, coagulopathy, placental abruption, placenta previa, vasa previa, local causes in the cervix such as a polyp, a laceration, an ectropion or cancer, preterm labour, and uterine rupture.

Causes and risk

The risk factors for placenta previa are increased age in the mother, over 35 years, multiparity, smoking, a previous placenta previa, a previous cesarean section, uterine anomalies, multiple pregnancy and intrauterine surgery. Smoking is the one avoidable risk factor among them.

How it presents

The two big causes separate on pain.

Placenta previa bleeds without pain: intermittent fresh bleeding in the late second or third trimester, a relaxed uterus on abdominal examination, and a fundal height equal to the gestational age.

Placental abruption is the premature separation of a normally placed placenta, and the plane of separation is the spongy layer of the decidua basalis. It comes in two forms. In concealed abruption there is a retroplacental hematoma; the bleeding may be invisible while the woman is in shock, the fundal height is greater than the gestational age, and this is the more dangerous form because DIC is more common in it. In revealed abruption the bleeding is visible.