Maternal occupation and adverse pregnancy outcome were examined in 1980. Sources of information were birth and fetal death certificates. Questionnaires were sent to mothers, to hospitals where the deliveries occurred, to attendants at delivery, and to providers of diagnostic or treatment radiation during the 12 months before delivery. Four pregnancy outcomes were examined: live births, low birth weight (less than 2,500 grams), malformations, and late (28 weeks or more) fetal deaths. Employed mothers were asked for chief job activity. National estimates and percentages were derived from the sample for respondents only. An estimated 2,944,580 live births and 14,796 fetal deaths occurred among married females. An estimated 169,775 births were low birth weight infants, and 246,200 live born infants had malformations noted at time of birth. Nearly 70 percent of the 62 percent employed mothers of live born children worked in professional and related services, wholesale and retail trades, and manufacturing. Professional and related service industrial workers were the largest proportion of employees in all pregnancy outcome groups; proportions varied little across the pregnancy outcome categories. A greater proportion of females experiencing fetal deaths were employed in manufacturing industries compared to those delivering live babies. Compared to unemployed mothers, a larger proportion of employed mothers were 20 to 29 years old, college educated, received early prenatal care, and drank alcohol during pregnancy.