This study aimed to evaluate (i) longitudinal fluctuations and considerable changes in adult fear at five data-collection points during a 2.5-yr period and (ii) the stability of symptoms of depression in dental fear-change groups. Pilot data from the FinnBrain Birth Cohort study, of 254 families expecting a baby, were used. Data-collection points (DCPs) were: 18-20 and 32-34 gestational weeks; and 3, 12, and 24 months after delivery. At baseline, 119 women and 85 men completed the Modified Dental Anxiety Scale (MDAS) questionnaire. At all DCPs, 57 (48%) women and 35 (41%) men completed MDAS. Depression was measured using the Edinburgh Postnatal Depression Scale. Changes in MDAS were analyzed using general linear modelling for repeated measures. Stability of dental fear was assessed using dichotomized MDAS scores. Dental fear among women decreased statistically significantly in late pregnancy and increased thereafter. Among men, dental fear tended to increase in late pregnancy and decreased afterwards. Depression scores varied in high and fluctuating fear groups but the differences diminished towards the last DCP. Dental fear among adults experiencing a major life event does not seem to be stable. Clinicians should take this into account. The mechanisms behind these changes need further research.