This project investigates the relationship between migraine headache and other diseases based on the data collected from the large group of gravidae in the Collaborative Perinatal Project. Subgroups of women characterized by the absence and presence of migraine and other recurrent headaches prior to or during pregnancy, were identified. Characteristics of these subgroups were examined for a variety of demographic, sociological, medical and obstetric factors, as well as the association of headache with other disorders. Results indicate that pregnant women with a migraine history had higher rates of smoking and of other symptoms and illnesses than women without a migraine history, and the presence of smoking history was associated with the prevalence of other symptoms and illnesses. Although there is no evidence that cigarette smoking might trigger or exacerbate migraine attacks in these women, smoking might have an additive effect on the association of migraine conditions with heart and thrombotic diseases, some respiratory and allergic diseases and peptic ulcer. A manuscript has been published in Archives of Neurology, Vol. 44, 1987. Children of mothers with a history of migraine appear to have higher incidence of some infectious and allergic diseases than children born to mothers in the non-migraine group. Statistical investigation of the latter results has revealed an association of occurrence of bronchial asthma in children born to mothers with migraine, even after partitioning out the potential influence of maternal asthma and allergies. Other factors such as pregnancy complications including placental and/or uterine bleeding disorders, maternal smoking, sex, respiratory infections, and other allergic diseases in children are also being examined for their possible influence on this association.