Short-chain fatty acids (SCFAs) are carboxylic acids with carbon atom numbers less than 6, which are important metabolites of gut microbiome. Existing research shows that SCFAs play a vital role in the health and disease of the host. First, SCFAs are the key energy source for colon and ileum cells, and affect the intestinal epithelial barrier and defense functions by regulating related gene expression. Second, SCFAs regulate the function of innate immune cells to participate in the immune system, such as macrophages, neutrophils and dendritic cells. Third, SCFAs can also regulate the differentiation of T cells and B cells and the antigen-specific adaptive immunity mediated by them. Besides, SCFAs are raw materials for sugar and lipid synthesis, which provides a theoretical basis for studying the potential role of SCFAs in regulating energy homeostasis and metabolism. There are also studies showing that SCFAs inhibit tumor cell proliferation and promote apoptosis. In this article, we summarized in detail the role of SCFAs in immunity, inflammation and metabolism, and briefly introduced the role of SCFAs in tumor cell survival. It provides a systematic theoretical basis for the study of SCFAs as potential drugs to promote human health.

Pregnancy is a complicated and delicate process, the maternal body undergoes changes on hormones, immunity, and metabolism during pregnancy to support fetal development. Microbiomes in the human body mainly live in the intestine, and the human gut microbiomes are complex, which composed of more than 500 to 1500 different bacteria, archaea, fungi, and viruses. Studies have shown that these microbiomes are not only involved in the digestion and absorption of food but also indispensable in regulating host health. In recent years, there has been increasing evidence that microbiomes are important for pregnant women and fetuses. During pregnancy, there will be great changes in gut microbiomes. Regulating gut microbiomes is beneficial to the health of the mother and the fetus. In addition, many complications during pregnancy are related to gut microbiomes, such as gestational diabetes, obesity, preeclampsia, digestive disorders, and autoimmune diseases. Moreover, the microbiomes in mother's milk and vagina are closely related to the colonization of microbiomes in the early life of infants. In this review, we systematically review the role of maternal microbiomes in different gestational complications, and elucidate the function and mechanism of maternal microbiomes in the neural development and immune system of offspring. These will provide a clear knowledge framework or potential research direction for researchers in related fields.