There have been recent major advances in obstetric ultrasound, both regarding technologies and expertise, such that high-resolution antenatal structural imaging, determination of maternal and fetal blood flow parameters and 3D and 4D ultrasound, are part of routine practice. This has resulted in changes in the way antenatal and obstetric care is now delivered. For example, antenatal and obstetric management of pregnancies complicated by intrauterine growth restriction (IUGR) and pre-eclamptic toxaemia (PET) is now dependent on several sonographic techniques including Doppler indices of the umbilical cord and maternal uterine arteries, hence ultrasound findings have become an increasingly common indication for placental pathological examination. The quality of specialist surgical pathology reports is related to pathologist expertise and, regarding the placenta, it has been reported that about 40% of placental diagnoses made by non-specialist pathologists were incorrect on specialist review, 90% being errors due to unrecognised lesions and 10% erroneous diagnoses,1 many of these differences possibly being related to pathologist unfamiliarity with current obstetric technologies. This review aims to provide an overview of relevant obstetric ultrasound techniques and their clinical relevance to the diagnostic pathologist, primarily focussing on conditions with specific placental implications. There are several detailed texts regarding histological findings and their implications of placental pathological lesions,2-4 and therefore this review will specifically discuss the pathological correlates of sonographic findings, with details of the specific histological entities being found elsewhere. The aim of pathological examination of the placenta is to determine the pathological basis for the clinical findings and advance understanding of the pathophysiology of pregnancy complications.