Vasa praevia: a missed diagnosis.

Vasa praevia is an uncommon obstetric complication, which if undiagnosed is associated with a high fetal mortality because of the rapid haemorrhage from tearing of fetal vessels resulting in fetal exsanguinations. Antenatal diagnosis in most cases is not made and therefore prevention of fetal death is not possible. Outcome depends primarily on prenatal diagnosis and caesarean delivery at 36 weeks or even earlier. Advances in ultrasound have led to an improved ability to diagnose this condition. Evaluation of high-risk patients with transvaginal colour flow Doppler ultrasound should be considered and should be included in the protocol for routine obstetrics scan. We report three cases of vasa praevia presenting as ante-partum and intra-partum bleeding. Two of them had associated suspected low-lying placenta. This occurred within 4 years (2002-2006) in a small DGH with a delivery rate of 1,800 per year. The purpose of writing these case reports is to warn others of the need for vigilance antenatally, especially with a low-lying placenta, velamentous insertion of cord, IVF and multiple pregnancy. Colour Doppler should be used to visualise blood vessels in these high-risk cases and elective caesarean section should be performed at 35-36 weeks in cases diagnosed as vasa praevia.