The purpose of this study is to assess the risk of congenital cytomegalovirus (cCMV) infection in newborns born to seropositive women.

This study will be conducted at several Maternal and Child Health Hospitals (MCHHs) in China and the research activities will be integrated with routine medical services during pregnancy at the study sites.The investigators will build a perspective cohort study enrolling ~8000 pregnant women elder than 18 and following up their newborns at specific MCHHs.As a first step, The investigators will work with these hospitals to recruit the subjects. After being informed, the participants' remaining blood and urine samples (after their medical examinations) at their early, medium and late stages of pregnancy will be collected , and their newborns' urine and saliva samples will be collected after delivery. The aim of this study is to enroll 5000 series mother-newborns.

Inclusion Criteria:

• Females aged 18 and older
• Pregnancy confirmed by ultrasound
• Come to MCHHs for "Pregnancy Registry" within 24 weeks of pregnancy

Exclusion Criteria:

• Not capable of complying with study procedures, or having a psychosis, two-stage affective psychosis, or have a tendency to suicide
• Having any autoimmune diseases (include systemic lupus erythematosus, rheumatoid arthritis), immunodeficiency (e.g. AIDS), chronic disease history such as cancers

This study will enroll ~8000 pregnant women aged 18 years and above at MCHHs. Pregnant women who meet the inclusion/exclusion criteria will be enrolled. All inclusion and exclusion criteria will be reviewed by investigators or qualified designees to ensure that each subject is qualified for the study. In general, those whose newborns (including early birth, any congenital anomaly) are successfully followed up remain in the study population. However, those with adverse pregnancy outcomes captured in the MCHHs, such as abortion and still birth, etc., will also be the investigators' subjects even though we cannot have newborns' urine/saliva samples.