Background: At present, an instrument with a disciplinary, valid, reliable and culturally adapted theoretical support is required to measure the process of becoming a first-time mother.

Methods: Adaptation scale and validation scale study. Experts of Colombia participated in the facial validity and the content validity, for cultural adaptation. The content validity index and factor analysis were performed. A total of 282 first-time mothers participated in the survey to establish construct validity and reliability. Reliability was estimated using Cronbach's alpha coefficient.

Results:he cultural adaptation was achieved. Facial validity for mothers was found as follows: high comprehension (97%). For experts: high comprehension (95.50%), high clarity (94.38%) and high precision (93.58%). In relevance, the content validity index was 0.97 (highly relevant) and in pertinence, the content validity index was 0.96 (highly pertinent). In the factor validation, ten factors that accounted for 66% of the variance were identified. Cronbach's alpha value of the scale was found to be 0.96 CI95% (0.95-0.97).

Conclusion: The scale of Adoption of the Maternal Role culturally adapted in Colombia is valid and reliable for first-time mothers with full-term babies. This scale makes possible to identify the level: low, medium or high, of the process of becoming a mother and can be used to evaluate interventions focused on favoring the process of becoming a mother.