Introductory Chapter: Environmental, Genetic, and Epigenetic Risk Factors in Adverse Pregnancy and Birth Outcomes

It is well established that pregnancy complications and adverse birth outcomes are important public health concerns in both developed and developing countries. Prenatal development refers to the process in which an embryo and later fetus develop during gestation. Each pregnancy can be divided into three trimesters of approximately 3 months each. A normal, full-term pregnancy lasts about 40 weeks. During the 40 weeks of pregnancy, the embryo and fetus are heavily influenced by environment (Figure 1).