This area is concerned with those factors, both normal and abnormal, that influence the course and outcome of pregnancy. Information is sought about maternal physiology, environmental variables, conditions and treatments occurring during pregnancy, which contribute to adverse outcomes (e.g., low birth weight infants). Examples of interest include but are not limited to studies on: elucidating the mechanisms involved in the pathophysiological states of pregnancy; the health impact on mother and infant of pregnancy related disorders; pathogenesis of symptomatic and asymptomatic maternal infections and their effects on fetal development with the aim of improving treatment and prevention; the effect of maternal medications and mother's use and abuse of drugs on fetal development; and adolescent pregnancy.