Ancillary study of the PregMouv study which aims to evaluate an intervention allowing the best adherence of women in terms of physical activity. Several types of interventions are therefore planned in this study: no intervention, physical activity sessions in person, by videoconference or mixed (in person and videoconference) with accelerometer assessment of the level of physical activity practiced (in the form of energy expenditure, in MET). Thus, for our ancillary study, a comparison of the cardiac variability of newborns will be carried out according to the level of physical activity practiced by the mother regardless of the intervention she benefited from within the framework of the PregMouv study. A comparison of the average saturation and the time spent below 90% saturation will be carried out via a continuous recording of saturation by oximetry. A longitudinal follow-up for the assessment of height and weight growth (from growth curves) and neurodevelopment (by clinical examination and self-questionnaire) is also planned until the child is 2 years old.