The effectiveness of public health nursing interventions with prenatal clients was summarized from 17 studies, conducted between 1963 and 1988, that were identified through a comprehensive reference search. The review indicated that public health nursing interventions can increase birthweight, and the use of prenatal medical services, nutritional services, and childbirth classes. Because of methodological problems, however, it is difficult to conclude with certainty that such interventions make a significant difference in client outcomes. These problems included lack of construct validity, lack of specification of interventions, small convenience samples, lack of power to detect small treatment effects, nonexperimental research designs, lack of reliability information, and self-selection and history biases. To overcome these problems, the authors suggest the use of conceptual frameworks, power calculations prior to initiation of research, experimental or quasi-experimental designs, replication of research with different populations, and the calculation and reporting of reliability information.