Developing and Testing a Preventive Primary Care Parenting Intervention to Strengthen Parent-Infant Co-Regulation in Families Experiencing Early Regulatory Difficulties

The goal of this randomized controlled trial is to evaluate the effectiveness of a structured parenting support program for families with young infants experiencing early regulatory difficulties. Participants are families with infants approximately 3 months of age who score above a predefined threshold on a screening questionnaire assessing early regulatory problems. The main questions this study aims to answer are: * Does participation in the parenting support program reduce parental stress and improve parental self-efficacy from baseline to post-intervention? * Does the intervention reduce infant regulatory problems (e.g., excessive crying, feeding difficulties, and sleep problems) at 6-month follow-up (i.e., when the child is approximately 12 months old)? Researchers will compare families receiving the structured parenting support program to families receiving usual care to evaluate the effects of the intervention. Participants will complete questionnaires when the infant is approximately 3-4 months old (baseline), around 6 months of age (post-intervention), and follow-up assessments will be conducted when the child is approximately 9 and 12 months old. If assigned to the intervention group, participants will attend one individual session and five group sessions led by trained psycho-educators and receive access to psycho-educational content through a mobile application.

Inclusion Criteria: * Parent (or primary caregiver) of an infant aged approximately 3 months at enrollment. * Aged 18 years or older. * One parent has completed the brief screening questionnaire and scored above a predefined cutoff indicating elevated levels of infant regulatory problems and eligibility for the intervention. Exclusion Criteria: * Insufficient proficiency in Dutch to understand study materials or participate in intervention sessions * No access to the internet or a compatible device required to use the mobile application