3.1. Participants Characteristics
In total, 39 women who returned pregnancy questionnaires also returned postnatal questionnaires at one or more time points (38%) between March 2018 and June 2019. At 3-, 6-, 9- and 12-months postnatal, the socio-demographic, diet and PA data were available for 24 (23.1%), 22 (21.2%), 12 (11.5%) and 20 (19.2%) women, respectively. Weight data were available for 20 (19.2%), 22 (21.2%), 11 (10.6%) and 20 (19.2%) women respectively. At nine months postnatal, one NHS trust did not send out any questionnaires, which explains the relatively low response at this postnatal time point compared with others. There were no significant differences in the socio-demographic characteristics of the women who returned the questionnaire compared to those who did not (Across the four postnatal time points, there was minimal difference in the median BMI, ranging from 35.0 to 36.6 kg/m