AbstractHypnosis may play an important role in reducing preterm labour for patients who have higher levels of psychosocial stress. This study examines the rate of late‐preterm birth in a hypnosis group (directed to all women) and a historical control group. From July 2007 all women (n = 64), who were in their 28th to 34th weeks' gestation, were offered self‐hypnosis training using the hypnoreflexogenous protocol after Hüsken‐Janßen and Schauble. Expectant mothers with uncertain anticipated days of delivery were excluded. All women who delivered after 31 weeks' gestation served as a control group (n = 2135) from January 2006 till June 2007. In the hypnosis group there were three preterm deliveries (4.7%) (before 37 + 0 weeks' gestation) whereas in the control group there were 220 preterm deliveries (10.3%) (p = 0.01). Average cigarette usage during the current pregnancy was lower in the hypnosis group (p = 0.02). Higher work‐educated employments (p = 0.01), higher age of the mother (p < 0.001) and fewer previous pregnancies (p < 0.03) were found in the hypnosis group. Preterm birth correlated with the number of previous pregnancies (−0.38; p < 0.001) but not with smoking. Hypnosis was shown to be effective therapy without side‐effects, which can reduce preterm delivery. This clinical study showed a significant prevention of preterm delivery. Prospective randomized controlled studies are required to evaluate fully the preventive value of clinical hypnosis. Copyright © 2009 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.