The Study of Free Gas in the Foetus as a Sign of Intra-uterine Death

Abstract

Thirty-one instances where gas was observed in the foetus after death are reviewed. Gas was present in 45 per cent of cases where intra-uterine death was observed on the ante-natal radiograph. The shortest interval between death and gas formation, as observed on the foetal radiograph, was 55 minutes and on the ante-natal film 12 hours. In 70 per cent of the series gas was demonstrated within seven days of foetal death. It was mainly intravascular, principally within the heart, portal veins, aorta, iliac vessels and umbilical cord. In four instances it was seen outside the foetal circulation. True Spalding's Sign was observed in only 29 per cent of the series whereas disalignment of the sutures occurred in 48 per cent of the total. Chemical analysis of the gas showed it to consist, on average, of 70 per cent carbon dioxide and 25 per cent oxygen with an average blood Ph value of 6·39. An “in vitro” experiment produced gas of identical chemical composition and blood Ph value. Gas was also formed, in a small amount, by artificially lowering the blood Ph with lactic acid. A possible explanation of gas formation is propounded.