Abruptio placentae: apparent thickening of the placenta caused by hyperechoic retroplacental clot.

Antepartum bleeding occurs in approximately 3.5 per cent of third trimester pregnancies, with placental abruption being the causative factor in up to 32 per cent of cases. 1 Although the diagnosis of abruptio placentae is often based solely on the clinical examination, sonographic studies may confirm the condition. Primary sonographic findings are visualization of a retroplacental mass of varying echogenicity and/or bulging of the chorionic plate. This mass effect has commonly been described as hypoechoic or anechoic and is related to bleeding or infarction. 2·3 In this report, two unusual cases are presented of abruptio placentae which initially presented as homogenously enlarged placentas. In the proper clinical setting, this finding should heighten suspicion of abruptio placentae.