GESTATIONAL-AGE, BIRTH-WEIGHT, AND PERINATAL DEATH AMONG BIRTHS TO NORWEGIAN FARMERS, 1967-1991

Perinatal health was investigated by linkage with the Medical Birth Re gistry of Norway for 192,417 births that took place between 1967 and 1 991 among parents identified as farm holders in Norwegian agricultural censuses in 1969-1989. In a comparison with 61,351 births to nonfarme rs in agricultural municipalities, farmers' births had an advantageous distribution of gestational ages and birth weights. Perinatal mortali ty was similar in the two groups, but the proportion of late-term abor tions (gestational weeks 16-27) was higher among farmers' births (odds ratio (OR) = 1,9, 95% confidence interval (Cl) 1.6-2.3). Exposure ind icators were classified on the basis of information given in the agric ultural censuses and climate data for the grain harvest seasons of 196 6-1991. The main hypotheses were that perinatal death is associated wi th parental exposure to pesticides, Toxoplasma contracted from infecte d sheep or pigs, or mycotoxins found in grain farming, There was no co nvincing evidence that perinatal death is associated with use of pesti cides, sheep farming, or pig farming, The increase in late-term aborti on among the farmers could to some extent be attributed to an excess o f midpregnancy (weeks 21-24) deliveries among grain farmers; grain far mers had 132 deliveries at this time in pregnancy (2.8 per 1,000 pregn ancies), while the nongrain farmers had 236 deliveries in midpregnancy (1,8 per 1,000). The authors found odds ratios (95% CI) that indicate d that grain farming risk was higher after the harvest (1.8, 1.1-2.8), in seasons with a poor quality harvest (2.4, 1.5-3.8), and in pregnan cies with multiple births (3.8, 1.7-8.2), These results support the hy pothesis that occupational exposure to mycotoxins in grain induces lab or at an early stage of pregnancy.