Background: From a life course perspective, pregnancy leads to a rise in nutrition awareness and an increase in information flow in favour of adopting healthier eating behaviours. This qualitative study was designed to better understand the determinants of eating behaviours in French pregnant women by focusing on their concerns, attitudes and beliefs and their nutrition-related information seeking practices. Methods: Seven focus groups were conducted, involving a total of 40 French pregnant women. An inductive thematic approach, adapted from the grounded theory, was adopted to analyse the data. Two major themes were identified: eating behaviour and nutrition-related information behaviour. Results: The eating behaviour theme was divided into four sub-themes using the attribution theory. Three external causes affected the eating behaviour of pregnant women (food restrictions, physiological changes and weight gain), and led to frustration and a perceived loss of control. By contrast the adoption of a healthier diet was perceived as internal by pregnant women, and resulted in self-fulfilment and empowerment regarding the health and the well-being of their baby and themselves, and their weight gain management. Greater attention was paid to nutrition-related information obtained from healthcare providers, the social environment and the mass media. Information was passively absorbed or actively sought by pregnant women, but most was perceived as contradictory, which led to confusion. Conclusion: Pregnancy is accompanied by a rise in nutrition awareness, substantiated by eating behaviour modifications due to external and internal causes. However, conflicts between and within information sources result in confusion that can limit the adoption of healthier eating behaviour.