Measures

Details of the measures used in the present study are presented in Additional file 1. Socio-demographic characteristics including age, education level, place of residence, and pregnancy-related characteristics including parity, gestational age, and whether they had any pregnancy-related complications were collected. Participants were also asked to report whether their place of residence was locked down, whether they have been quarantined, and whether someone they personally knew were infected with COVID-19.

Cognitive factors. Participants were asked to rate the likelihood that the COVID-19 would be under control in the coming month, and if the COVID-19 would pose long term physical harm to human.

Social factor. Participants were asked to rate the level of social support they have obtained during the COVID-19 outbreak period.

Personal preventive behaviors. Participants were asked to report their frequency of wearing a face mask when going out, and their frequency of washing hands with soap everyday.

Mental health. Depression was measured by the 9-item Chinese version of Patient Health Questionnaire-9 (PHQ-9) [18]. Anxiety was assessed by the 7-item Chinese version of General Anxiety Disorder scale (GAD-7) [19].