IS THERE TRANSPLACENTAL TRANSFER OF ASBESTOS - A STUDY OF 40 STILLBORN INFANTS

An autopsy study was conducted to investigate whether there is transpl acental transfer of asbestos in humans. The asbestos burden of lung, l iver, skeletal muscle, and placenta digests of 40 stillborn infants wa s determined using a bleach digestion method. The fibers detected in t he tissue digests were characterized as to the type of asbestos, using electron microscopy, energy-dispersive x-ray analysis, and selected-a rea diffraction analysis. Placental digests of 45 full-term, liveborn infants were similarly processed as controls. Low levels of small, thi n, uncoated asbestos fibers were detected in the placentas and organs of 37.5 % of the stillborn infants (15 of 40). The fiber sizes ranged from 0.05 to 5.0 mu m in length and 0.03 to 0.3 mu m in width, with a mean length of 1.15 mu m and a mean width of 0.069 mu m. Maximum numbe rs of fibers were found in the lungs (mean 235,400 fibers/g;n = 10), f ollowed by liver (mean 215,833 fibers/g; n = 6), placenta (mean 164,50 0 fibers/g; n = 4), and skeletal muscle (80,000 fibers/g; n = I). The fibers were detected at all stages of gestation and showed no associat ion with gestational age. A significant association was found between fiber presence and working mothers, and positive but nonsignificant as sociations were found with maternal history of drug abuse, previous ab ortions, and fetal maceration. No association was found between premat ure rupture of membranes and fiber presence. No fibers were detected i n the 45 placentas of the liveborn control infants. There was a highly significant difference in the asbestos fiber counts of the placentas of the stillborn and liveborn infants (P <. 001). Our studies demonstr ate the presence of short and thin asbestos fibers in stillborn infant s and their positive association with working mothers.