Large-scale survey data is widely used to study the intention to have a(nother) child. However, there are further opportunities to understand how these intentions are revised over the life course and the uncertainty surrounding them. We aim to further outline the importance of simultaneously considering change and uncertainty in fertility decision-making. Specifically, we identify uncertainty in the "probably not" and "probably yes" responses to questions on whether an individual intends to have a(nother) child, and compare the differences in individuals' stated intention between survey waves. Using panel data from the Generations and Gender Survey (GGS) for Austria, France, Hungary, Italy, and Poland, we study short-term followed by long-term (overall) fertility intentions. First, descriptive analyses compare and visualise the prevalence of uncertainty intentions at first and second wave using Sankey diagrams. Next, multivariate analyses on transitions in intentions focus on partnership and employment context. The results reveal that for both short-term and overall intentions, four in ten respondents are uncertain about intending a (further) child. Further, one in two report a different intention between waves, with changes mainly occurring from one "probably" response to another (e.g., "probably not" to "probably yes") or through a shift in increasing or lessening certainty (e.g., "probably yes" to "definitely yes"). The childless exhibit by far the greatest uncertainty and revision. Multivariate analyses show that partnership and employment are associated with gradual transitions and larger changes in intentions. Our results also show that fertility intentions form to a large extent along a spectrum of certainty-from "definitely not," to "probably not," to "probably yes," to "definitely yes," and finally to the birth of a child.