The presence or absence of fetal breathing movements (FBMs) in a 30 minute observation period was determined in 29 patients with abnormal contraction stress tests (CSTs). The study population included 14 patients with positive CSTs, 11 patients with equivocal CSTs, and four patients with unclassified CSTs. In patients with either an equivocal or a positive CST, the presence of FBMs was associated with a high incidence of false predictive tests. Conversely, the absence of FBMs in a patient with a positive CST was uniformly associated with intrapartum fetal distress. The presence or absence of FBMs was not helpful in assessing the patients with unclassified CSTs. These data suggest FBMs may be a useful means of evaluating the patient with a positive or equivocal CST.