A study of the effect of working as a coal miner during pregnancy was conducted. The study group consisted of 26 women selected by the Coal Employment Project, an advocacy group for female miners, who had been pregnant while working as coal miners. Subjects were interviewed by questionnaire to obtain information on occupational and reproductive history, occupational exposure, health conditions, outcome of primary pregnancy, and employer response and benefits. Of thirty three pregnancies that occurred, Seven were the second pregnancies experienced while working as a miner, eight pregnancies occurred to women working on the surface and 25 to subjects working underground. Seventy five percent of the subjects continued to work for at least 1 month after they were pregnant. Three subjects worked into the ninth month of pregnancy. Fifty eight percent of the subjects reported lifting objects weighing 40 or more pounds at least five times daily, 65 percent reported being exposed to loud or continuous noise, 33 percent were exposed to continuous whole body vibrations from machinery, and 20 subjects continued doing the same job. During 13 pregnancies the subjects requested a different job, but this was granted in only four cases. In 81 percent of the pregnancies the subjects were granted leave for delivery and recovery; 67 percent received sickness and accident pay. No financial benefits or compensation were received in 24 percent of the pregnancies. One pregnancy ended in miscarriage. Twenty three live births had slightly above normal birth weights. Two structural malformations occurred: Robinson's syndrome with hydrocephalus and duodenal atresia; and a positional deformity of the foot with a reduction deformity of the hand. The authors conclude that although the subjects were exposed to noise and whole body vibrations, conditions reported to cause reproductive effects in animals, it is not possible to determine if working in a coal mine affects pregnancy outcome.