Accidental Haemorrhage

Abstract

Edward Rigby of Norwich, in a treatise on uterine haemorrhage published in 1776, first shed light on the problem of bleeding from the vagina during later pregnancy. In this essay he differentiated between an accidental haemorrhage and the haemorrhage of a placenta praevia. From his observations accidental haemorrhage was defined as "bleeding from a normally situated placenta, after the 28th week of gestation, and up to the end of the second stage of labour."

Accidental haemorrhage is divided into three varieties:

1. Revealed Accidental Haemorrhage.-where the bleeding is entirely external;

2. Concealed Accidental Haemorrhage.-where there is no sign of blood externally;

3· Mixed or Combined Accidental Haemorrhage.-which shows features of both concealed and revealed.

The most important of these is the concealed variety and there are four ways in which a haemorrhage may remain concealed:

1. A retroplacental haemorrhage occurs in the central area of the placenta, but the margins of the placenta remain adherent to the uterine wall.

2. If the placenta becomes completely separated the membranes remain attached to the uterine wall.

3· The blood may burst through the membranes into the amniotic sac mingling with the liquor, and   immersing the foetus in a blood bath (Lesser 1951).

4· When the foetal head is accurately applied to the lower uterine segment so that the blood cannot make its way past it into the vagina.

In spite of these mechanisms it is much more common for blood to escape externally ; a concealed accidental haemorrhage thus becomes a mixed accidental haemorrhage.