[Scanning electron microscopic studies of the umbilical arteries and veins of newborn infants of smoking mothers].

We have examined the umbilical cord of ten newborn children of nonsmoking (five) and of smoking (five) mothers (10-20 cigarettes/day). The patients chosen for the study resulted "normal" before and during pregnancy. Immediately after delivery the umbilical cords were tied (to avoid collapse) and cut about 10 cm from the placenta. Umbilical cords were submitted to pressure-perfusion-fixation according to Kjelsen and Thomsen (7). Three randomly chosen specimens for SEM were cut and postfixation was performed in 1% buffered osmium tetroxide (pH 7.4) and after dehydration, were submitted to critical point drying (CO2), coated with gold palladium (sputtering technique), and observed by means of a Super ISI Mini SEM at 7,5 Kv. Luminal surfaces of umbilical arteries and veins from non-smoking mothers revealed a regular endothelial layer all over the surface. Large disendothelialised areas were instead found not only in arteries (1) but also in veins from newborn children of smoking mothers.