The purpose of this study was to determine by two groups of physicians the use of pregnancy bed rest, the types of activity restriction prescribed, if there is variability in prescription, and if side effects of this treatment are observed. A national survey of 44 directors of maternal fetal medicine (MFM) and a random selection of 47 practicing obstetricians certified by the American College of Obstetricians and Gynecologists (ACOG) was conducted. The survey contained questions about home and hospital bed rest and whether or not side effects of bed rest were observed. Physicians were also asked to indicate the type/degree of activity restriction prescribed for 16 diagnostic scenarios for women with mild hypertension, chronic hypertension, incompetent cervix, preterm labor, premature rupture of membranes, placenta previa, and twin pregnancy. Repeated measures analysis of variance was used to analyze the type of activity restriction prescribed at 20, 24, 28, 32, and 36 weeks' gestation. Results reveal that bed rest was prescribed extensively (89%-93%), but few any physical and psychologic side effects. Physicians in both groups demonstrated marked variability in prescribing the location (home or hospital) and the severity of activity restriction even when treating the same condition. MFM directors were significantly more likely to treat pregnancy-induced hypertension (p < 0.01) and placenta previa with hospital bed rest (p < 0.05). ACOG physicians preferred to prescribe either home or hospital bed rest across all diagnostic scenarios, whereas the prescription by MFM directors related more to the individual diagnosis than to a general preference. Choice of location of bed rest and the severity of activity restriction appear to be functions of physicians' practice style.