The long-term goal of the Human Genes and Microbiota in Early Life (HuGME) is to explore the short- and long-term effects of maternal microbiota during pregnancy and the microbiota colonization of their offspring early in life and their interaction with the host on maternal-offspring health consequences in later life in the born in Guangzhou cohort study in China. Identification of the effect of microbiota in early life, as well as environmental factors and microbe-host interaction, will lead to a better understanding of disease pathogenesis and provide a foundation for targeted mechanistic investigation into the consequences of microbial-host crosstalk for long-term health. It also can result in new strategies to predict and prevent diseases in later life.

Prenatal and early postnatal life represent critical windows for growth and cognitive and immune system development. In addition to genetics and host biology, the environment plays a critical role in the health of a child. One key player in this process is the maternal and infant gut microbiomes. The establishment and progression of the intestinal microbiota from birth to childhood are dependent on a range of factors, including maternal microbiota, diet, environment, and medical exposures. The host-microbial crosstalk during this time is thought to be involved in the pathobiology of later-life diseases, such as allergic disease, obesity, and neurodevelopmental delay. Although the microbiome and its importance for health have been extensively studied, it remains unclear how maternal microbiota-fetal interaction, the establishment, and progression of microbiota in infant adaptation to postnatal environmental exposures, and microbial-host crosstalk affect the health of the children in later life.

Hypotheses:

1. Maternal microbiota-fetal interaction has an essential effect on fetal immune system development and adverse pregnancy outcomes.
2. Host genes can shape infant gut microbial assembly and metabolism.
3. Early-life interactions between host genes and microbiota have an impact on immune system development and atopic disease in later life.
4. Co-metabolism of the gut microbiome and metabolites in the host affects childhood obesity
5. Early-life interactions between the host and microbiota have an impact on the neurodevelopment of the children.
6. Maternal microbiota influence the metabolism of the mother during pregnancy and postpartum.

Inclusion Criteria:

Pregnant women with < 20 weeks of gestation Pregnant women intended to eventually deliver in Guangzhou Women and Children's medical center Permanent residengts of families intended to remain in Guangzhou with their child for ≥3 years

Exclusion Criteria:

Refuses to have blood and stool samples stored at Born in Guangzhou cohort study Biobank.

Pregnant women attending their first routine antenatal examinations (usually around week 16) and their partners and offsrping