A study of pregnancy outcome in a small area around a chemical factory and a chemical dump.

Pregnancy outcome was studied in three parishes situated around a chemical factory from which air and water pollution was considered to have occurred. Data on health variables were mainly obtained from registries supplemented with hospital record information. No definite reproductive hazards could be demonstrated but an unusually high perinatal death rate among twins born in the area was noticed. The paper discusses principles involved in the design of a study of this type.