Abstract: Objective To explore the effect and critical period of pregnancy-related anxiety on internalization behavior of offspring. Methods A total of 3 474 pregnant women enrolled in Ma’anshan Birth Cohort （MABC） from May 2013 to September 2014 were included in follow-up study subjects. The information about demographic characteristics of pregnant was collected in early, second and third trimester of pregnancy. Used the completed self-made scale of pregnancy-related anxiety to assess pregnancy-related anxiety in each period, and the strength and difficulty questionnaire （SDQ） was used to assess internalization behavior of 4-year-old children. Results The detection rates of pregnancy-related anxiety in early, second and third trimester of pregnancy and internalization behavior of 4-year-old children were 19.9%（351/1 761）, 23.2%（559/2 410）, 22.6%（535/2 368） and 7.4%（185/2 513）, respectively. Student’s t-test analysis showed that internalization behavior score of offspring was significantly higher in the second and third trimester pregnancy-related anxiety group than that in the non anxiety group （both P<0.01）. Logistic regression analysis showed that pregnancy-related anxiety in third trimester of pregnancy was a risk factor for internalization behavior of offspring（OR=1.573）. Conclusion Pregnancy-related anxiety in third trimester of pregnancy is a risk factor for internalization behavior of offspring.

Key words: Pregnancy-related anxiety, Offspring, Children and adolescents, Mental health, Internalization behavior