Fear of childbirth (FOC) is associated with adverse outcomes, for the expecting woman as well as for her baby. In order to prevent and treat FOC, it is important to understand the psychological processes involved. Two potential key processes are intolerance of uncertainty and pain catastrophizing. The aim of this cross-sectional study was to explore intolerance of uncertainty and pain catastrophizing in pregnant individuals with severe vs. low/moderate FOC, and potential differences between nulliparas and multiparas. The sample of 332 individuals filled out a range of questionnaires, and were categorized as severe (