The experience of fatigue in early pregnancy was studied, using a general model of fatigue as the conceptual framework. A convenience sample of 30 women, age 20-35 years, who were at less than 20 weeks' gestation and without health problems were included in the study. Physiologic, psychological, and environmental factors were measured and related to the occurrence and intensity of fatigue. Pearson correlations and content analysis were used to analyze the data. Results showed that a large portion of the sample (90%) experienced fatigue and that this fatigue had a significant impact on their ability to maintain personal and social activities. Significant correlations were observed between fatigue and the physiologic variables of nausea and feeling tired upon awakening from sleep. There was no significant relationship between fatigue and environmental variables such as number of hours worked or the number of children living in the home. In addition, significant correlations were observed between fatigue and psychological variables that included depression, anger, anxiety, and confusion. These data suggest that fatigue is a significant problem for pregnant women and is not relieved by rest. These data further suggest that the fatigue may be related to other physiologic changes, perhaps hormonal, that mediate physiologic and psychological variables, including fatigue.