2.2. Measurements

During the initial visit with the midwife, the sociodemographic and obstetric variables of the pregnant women were recorded. The sociodemographic variables were health department (TV/EC), country of origin (Spain/Not Spain), age of the pregnant woman (years). The obstetric variables were previous pregnancies (0, ≥1), previous abortions (0, ≥1), and pregnancy weeks grouped as trimesters (T): 1 T (1–13 weeks), 2 T (14–27 weeks) and 3 T (28–40 weeks).

Their attitudes towards and experiences with flu vaccinations were obtained through a structured questionnaire designed ad hoc, through a telephone interview given to women who were in their postpartum period, ranging from 1 August 2016 to 30 October 2016. The questionnaire contained questions related to (1) the beliefs and opinions about vaccination in general; (2) a self-declaration of flu vaccination during pregnancy (vaccination coverage). Their answers were verified and corroborated by consulting the vaccination registry (NVR); (3) their reasons for rejecting the vaccine, for those who were not vaccinated, and the secondary effects for those who were vaccinated; (4) the attitude and predisposition for being vaccinated in a future pregnancy; (5) their own experience with the illness and/or the influenza vaccine throughout their lives.