ObjectiveTo compare mental distress and COVID-19-related family environment changes among pregnant women before and during the pandemic. MethodsIn a survey-based study in Lishui City, Zhejiang, China, pregnant women were recruited before (March-December, 2019; n = 2657) and during (January-August, 2020; n = 689) the COVID-19 pandemic. They completed the Symptom Check List-90 Revised (SCL90-R) questionnaire and Pittsburgh Sleep Quality Index (PSQI), and were asked about their families via the Family Environment Scale (FES). ResultsHigher SCL90-R scores of somatization (P = 0.003), depression (P = 0.043), anxiety (P = 0.041), hostility (P = 0.009), and others (P = 0.025) were reported by women during the COVID-19 pandemic. Sleep disorder also occurred more frequently among pregnant women during the pandemic (P = 0.002). Social environmental characteristics of families showed impaired family cohesion, and increased levels of conflict and independence during the pandemic (all P < 0.05). The FES score for family cohesion was negatively related with obsessive-compulsive, depression, anxiety, and hostility symptoms, whereas that for conflict was positively related with these symptoms (all P < 0.001). ConclusionThe mental health, sleep, and family environment of pregnant women was impaired during the COVID-19 pandemic. Potential protective factors including increased social support might help to mitigate long-lasting negative consequences. The mental health and sleep of pregnant women was impaired during the COVID-19 pandemic, and they experienced more stressful family events over the crisis.