Intrafetal gas.

Abstract

The earliest stage in pregnancy at which intrafetal gas can be demonstrated radiographically is the eighth month (2). Stewart (9, 10) in in vitro experiments found no relationship between the degree of maceration, the quantity of gas present, and the interval between fetal death and the radiographic examination. Gas has been seen in the retroperitoneal area prenatally and postnatally (8, 10), the peritoneal cavity prenatally and postnatally (5, 10), the thoracic wall antenatally and postnatally (10), the cranial cavity antenatally (6), the shoulder joint postnatally (1), and the vertebral canal prenatally (1). Case Material and Methods The radiographs of 53 cases of intrauterine fetal death, in which intravascular gas was demonstrated, were carefully reviewed with special reference to the possible coexistence of extravascular gas. All patients were examined by Edholm's method (3). We wished to investigate (a) the incidence of extravascular gas; (b) whether it is possible to distinguish intrafetal gas from maternal gas or from translucent tissue such as fetal fat, and (c) whether it is possible to determine radiographically in which vessels the gas is contained. In 2 of the 53 cases, gas was seen in the vertebral canal, and these were the only cases in which extravascular gas was identified. Case I: W. U., aged twenty-seven years, gravida III, Para 2. The patient was Rh-positive. The two previous pregnancies were uncomplicated; the present one had proceeded normally, the expected date of delivery being April 7. On April 13 fetal movements ceased, and on April 16 radiography disclosed intravascular gas and gas in the lumbosacral portion of the vertebral canal (Fig. 1). A second roentgen examination on April 17 demonstrated only the intravascular gas. Following medical induction of labor, the patient was delivered of a full-term, stillborn infant. Postmortem examination performed on April 18 showed gross maceration. Case II. K. E., aged twenty-three years, gravida II, Para 1. The previous pregnancy had been uneventful. During the present pregnancy Rh antibodies were demonstrated. The expected date of delivery was Aug. 18. Fetal movements ceased on July 7. Radiography on Aug. 7 disclosed gas in the lumbosacral portion of the vertebral canal coexisting with intravascular gas (Fig. 2). Following medical induction of labor, the patient was delivered of a full-term, stillborn infant. Postmortem examination performed twelve days after the radiographic study showed gross maceration. With Edholm's method the maternal intestines are displaced and not superimposed on the fetal shadows, thereby permitting a differential diagnosis between intrafetal and maternal gas to be made with confidence. To make certain that the streak of translucency in the fetal vertebral canal actually represented gas (Figs. 1 and 2), the lateral films taken prenatally by Edholm's method in 90 cases of intrauterine pregnancy, in which the fetus was alive, were also carefully reviewed.