ASSESSMENT OF ASBESTOS BURDEN IN THE PLACENTA AND TISSUE DIGESTS OF STILLBORN INFANTS IN SOUTH TEXAS

The primary aim of this prospective study was to examine the tissues a nd placentas of autopsied stillborn infants for presence of asbestos f ibers, Asbestos burden of lung, liver, skeletal muscle, and placenta d igests of 82 stillborn infants was determined using standard bleach di gestion technique. The digests were examined by electron microscopy, a nd the types of fibers determined using energy dispersive x-ray analys is and selected area diffraction analysis. Digests of 45 placentas col lected from deliveries of liveborn healthy infants were processed and examined similarly as controls. Asbestos fibers were detected in 50% o f the fetal digests and 23% of the placental digests of stillborn infa nts. Of the fibers present, 88% were chrysotile, 10% were tremolite, a nd 2% were actinolite and anthophyllite. Fibers measured 0.5-16.73 mu m in length (mean 1.55 mu m), and 0.03-0.8 mu m in width (mean 0.098 m u m). Lungs were most frequently positive for fibers (50%), followed b y muscle (37%), placenta (23%), and liver (23%). Mean fiber counts wer e highest in the liver (58,736 f/g), followed by placenta (52,894 f/g) , lungs (39,341 f/g), and skeletal muscle (31,733 f/g). Digests of 15% of the control placentas also showed asbestos fibers, although in ver y small numbers. The mean fiber count of the stillborn placentas (52,8 94 f/g) was significantly higher than the mean fiber count of the cont rol placentas (mean 19 f/g) (p = 0.001). A highly significant associat ion was found between fiber presence in stillborns and a maternal hist ory of previous abortions (p = 0.007). A significant association was a lso found between fiber presence and placental diseases (p = 0.041). A n association was suggested between working mothers and fiber presence (p = 0.19), although it did not reach statistical significance. The s tudy documents the presence of small and thin asbestos fibers in still born fetal tissues and placenta. Significantly higher number of fibers were found in stillborn tissues compared to controls (liveborn placen ta). The absence of a maternal history of asbestos-related occupations suggests that the fibers may have been acquired through environmental exposure.