Chapter 17 - Hormones in Pregnancy and the Developmental Origins of Health and Disease

Summary

The Developmental Origins of Health and Disease (DOHaD), also termed developmental programming, refers to adaptations during development that predispose an individual or a population towards later life noncommunicable disease (NCD) conditions or chronic diseases. The developmental trajectory of an individual is determined broadly by the interaction between that individual’s genes and the environment. “Environment” in this sense may include maternal or paternal factors, influences such as nutritional status before or during pregnancy, stress and exposure to contaminants, drugs or alcohol; and maternal diseases of pregnancy that influence transport of substrates and nutrients across the placenta (e.g., preeclampsia, placental insufficiency); and pre-term birth; factors that occur before or around the time of conception, during gestation or in the period after birth; the so-called First 1,000 Days. The interactions between genes and environment determine not only the developmental processes of the fetus and placenta leading to short term morbidity (low birth weight) and mortality, but also long term morbidity of multiple systems including neurodevelopmental disorders such as learning difficulties, poor developmental trajectories and cognitive development, mental health and behavioral disorders in children, and metabolic disorders such as obesity and diabetes. In later life, developmental programming contributes to heart disease such as hypertension and coronary heart disease, type II diabetes, obesity, immune, behavioral, and neurological disorders.

The mechanisms underlying developmental programming can result from structural changes in tissues or organs, effects on germ cells or stem cells, alterations in the microbiome, or in core inflammatory and immunological processes. There are clear sex differences in these responses, strong intergenerational effects, and variable vulnerability across the life course. Many adjustments occur as adaptive fetal responses to adversity or stress, such as hypoxemia or inappropriate nutrient supply, to ensure survival. The placenta plays a critical role in developmental programming, both in regulating the impact of maternal influences on the fetus, and through its direct impact on fetal development.