Reproduction and exposure to lead.

A study on spontaneous abortions and twinning rate was carried out in a commune with a lead smeltery and in a control commune without a specific source of lead exposure. For a period of 20 years (1961-1980) information on spontaneous abortions was recorded from vital statistics data. Data on twin deliveries were obtained from the birth certificates. The additional information regarding sex of twins, maternal age of delivery and mother's and father's occupations were recorded by an interview. To each twin birth two singleton births were matched by the area of residence and date of birth. Pollution measurements data on lead, zinc and cadmium were also evaluated. The average annual rate of spontaneous abortions in the commune with a lead smeltery was 12/1000 and in the control commune 6.7/1000 fertile women. The cumulative rate of twin births was 2.4/1000 inhabitants in the commune with a lead smeltery and 2.6/1000 inhabitants in the control commune. However, in the commune with a lead smeltery in the area actually exposed to lead the cumulative rate of twin deliveries over 20 years was 1.7/1000 inhabitants and in the rest of the commune it was 2.7/1000 inhabitants. The results indicate a possible interference of lead exposure with reproduction.