The objective of this study is to research the relationship between maternal exposure to environmental factors and fetal congenital heart disease in a community-based case-control study.

This is a community-based case-control study in SHANGHAI,a municipality in CHINA. Cases will be identified from maternity centers. Matched controls will be accrued from the same region as the case came from. Pregnant cases and their controls are women (18-45 years). Cases are gravidas with fetal congenital heart disease diagnosed by echocardiography in 16th-29nd of gestational weeks. Controls are pregnant women without fetal congenital heart disease diagnosis. Only gravidas who are willing to have complete pregnancy checks and finally delivery or abortion in the hospital are interviewed are eligible for the study. About 2 controls matched by year of birth and region will be allocated to each case. A standardized questionnaire will be used for all cases and controls. Field investigations are also conducted for them by quantitative measurement of some chemical, physical and nutritional factors related indicators may affect fetal cardiovascular development. Study participants will be asked for their informed consent.

Inclusion Criteria:

1. Gravida with singleton pregnancy taking fetal echocardiography in 16th-29nd of gestational weeks.
2. Complete pregnancy check in the hospital, and finally delivery or abortion in the hospital.
3. On the basis of informed consent，willing to cooperate with our group.

Exclusion Criteria:

1. Pregnant women with serious pregnancy complications .
2. Pregnant women suffering from mental illness, can't take care of themselves. 3) Fetus diagnosed with chromosomal abnormalities in pregnant women .

4）Repeated explanation does not cooperate in pregnant women.

Gravidas with singleton pregnancy living in SHANGHAI