NO OBVIOUS SPATIAL CLUSTERING OF TWIN BIRTHS IN SWEDEN BETWEEN 1973 AND 1990

The aim of this work was to ascertain whether spatial clustering of tw in deliveries occurred in Sweden between 1973 and 1990. Since 1973, th e Medical Birth Registry (MBR) has gathered information on all births in Sweden. Between 1973 and 1990, there were 17,067 twin deliveries. T he MBR records data on pregnancies, deliveries, and the neonatal perio d, including parturients' domicile. TO test the hypothesis that atmosp heric pollution from refuse incinerators increases the incidence of tw in deliveries, the periods before and after the commissioning of 14 su ch plants were compared. There was no apparent increase in the number of parishes or municipalities having a relative excess of twin deliver ies. In the vicinity of one plant, there was a significantly increased number of twin deliveries, whereas in another, there was a significan t decrease. There was no spatial clustering when the incidences of twi n delivery were compared among parishes, municipalities, and areas nea r incinerators. (C) 1998 Academic Press.