BACKGROUNDAntenatal mental disorders are associated with maternal and fetal adverse events. Previous studies have been focused on the postpartum period, rather than pregnancy, yet the association of risk factors with prenatal depression and anxiety through pregnancy has been rarely reported. This study aimed to identify the risk factors of prenatal depression and anxiety, and access their potential roles in developing mental disorders during pregnancy.METHODSThis is a prospective study in 6470 participants from the Tianjin Birth Cohort in China (TJBC). The degree of prenatal depression and anxiety was evaluated using a questionnaire of Self-Rating Depression scale (SDS) and Self-Rating Anxiety Scale (SAS), which was given to pregnant women at 15-27 (Stage-2), and 28-41 (Stage-3) gestational weeks. The questionnaire also collected demographic, personal, and lifestyle information. The association of different factors with SDS/SAS score was examined by logistic regression analysis.RESULTSWe observed an overall depression rate of 12.4 % and an overall anxiety rate of 7.7 % during pregnancy in the TJBC. In the Stage-2, the depression rate was 14.5 % and the anxiety rate was 9.5 %. In the Stage-3, the depression rate dropped to 9.7 % while the anxiety rate dropped to 5.3 %. With univariate analysis, we found that age, education, social support, marriage satisfaction, secondhand smoke (SHS), sleeping time and stress were common factors of prenatal mental health. Working status, family income, gravidity, smoking, electronic using, recreational activities were associated with depression risk, whereas BMI, disease history, changing eating habits, and feeding animal were associated with anxiety risk. Using logistic regression, we found that low education level, low social support, low marriage satisfaction, thyroid disfunction, Stage-2(second trimester), and stress were related to prenatal mental health.CONCLUSIONThe prevalence anxiety and depression in Tianjin is normal as national level. Age appropriateness, a good education level, sufficient social support, marital satisfaction, normal thyroid function, and absence of stress are associated with relieving depression and anxiety during gestation. However, due to individual difference, expectant mothers should seek professional support and guidance to address their mental health needs during gestation.