The Environmental Factors and Embryonic Development Project was set up to investigate environmental exposures and behavioral factors responsible for embryonic dysplasia and gestational complications in pregnant women.

The Environmental Factors and Embryonic Development Project is about to recruit pregnant women from 16 cities, including Beijing, Guangzhou, Jinan, Nanjing, Hangzhou, Wuhan, Zunyi, Xiangyang, Nantong, Suizhou, Huangshi, Changzhou, Suqian, Shiyan, Xiaogan, and Huanggang. The project plans to recruit 6000-12000 participants in each city. Biological samples, questionnaires and data for embryonic dysplasia and gestational complications of pregnant women will be collected. The study includes four stages. In the first stage, the investigators will identify external environmental factors and behavioral factors that are associated with embryonic dysplasia and gestational complications in pregnant women based on external exposure monitoring strategies. In the second and third stages, the investigators will conduct several nested case-control studies based on our prospective cohort. Internal exposure monitoring will be applied to identify environmental endocrine disruptors which are associated with embryonic dysplasia and gestational complications in pregnant women in the second stage. In the third stage, the investigators will conduct genome-wide association study (GWAS) to screen susceptible genes or polymorphisms that are associated with embryonic dysplasia and gestational complications in pregnant women, identify any gene-environmental interactions with reference to the findings of the 1st and 2nd stages, and finally establish a comprehensive disease risk prediction model. In the fourth stage, the investigators will build animal models in order to identify the mechanisms how high-risk environmental exposures or behavioral factors as identified in the above stages may lead to embryonic dysplasia and gestational complications in pregnant women. The research team of the 16 cities are from Peking University (Beijing), Sun Yat-sen University (Guangzhou), Shandong University (Jinan), Chinese People's Liberation Army Eastern Theater General Hospital (Nanjing, Nantong, Changzhou, and Suqian), Zhejiang University (Hangzhou), Huazhong University of Science and Technology (Wuhan, Xiangyang, Suizhou, Huangshi, Shiyan, Xiaogan, and Huanggang), Zunyi Medical University (Zunyi), respectively. The core members of each research team are composed of experts from different disciplines in the field of public health.

Inclusion Criteria:

1. pregnancy within 13 weeks;
2. age between 20-45 years;
3. natural conception;
4. singleton pregnancy;
5. living in the local area for one year or more.

Exclusion Criteria:

1. pregnant women with serious chronic diseases and infectious diseases (such as cancer, chronic cardiovascular and cerebrovascular diseases, chronic renal failure, HIV infection);
2. have participated in other scientific research projects;
3. refuse to participate or are unwilling to sign informed consent.;
4. are unable to guarantee delivery in our designated hospitals.

Pregnant women attending their first routine antenatal examinations.