Events at the earliest stages of life can have long-term effects. Obesity, heart disease, diabetes, cancer, hypertension, and other adverse health outcomes in adulthood have been linked to exposure to poor nutrition before birth. When small size at birth and in infancy is followed by rapid growth and being overweight in early childhood, risk of developing chronic diseases later in life is further increased. Similarly, when slow linear growth in utero is followed by failure to thrive during infancy and childhood, risk is increased for coronary disease and stroke.

How does this effect work? When the body’s organs and regulatory systems are forming, poor nutrition and too few or too many calories can permanently alter their structure and function. These changes are possible because, for each organ or system, a period of plasticity occurs during critical windows of development, making it possible for environmental influences to permanently affect gene expression and program developmental pathways.

Developmental plasticity makes it possible for organ systems to adjust their development in response to the nature and the timing of nutrition and other cues from the intrauterine environment. Such adjustments favor survival if similar conditions prevail after birth. For example, insufficient calories and nutrients in utero may trigger adaptive physiological mechanisms that encourage maximal use of available nutrients, conferring an adaptive advantage in the womb. However, if food is abundant in post-natal life, the same adaptations can be detrimental for weight control.

Maternal weight before pregnancy is a strong predictor for childhood obesity in offspring. Obese women have higher rates of large-for-gestational-age births, which increases a child’s risk for becoming obese. High-calorie intake early in life can affect fat cell development as well as how the brain regulates appetite, resulting in childhood obesity. When the obese child becomes an obese parent, the cycle continues.

The higher prevalence of obesity among women in lower socioeconomic groups suggests how health disparities can be initiated in the prenatal period. The evidence for the developmental origins of obesity presents a strong case for public health interventions that target the nutrition and health of young children, girls, and women through the child-bearing years, especially those from disadvantaged populations. The results of these efforts will influence the health and health equity of current and future generations.

Elizabeth Adams, PhD, RD, is an assistant professor in the Department of Public Health and Preventive Medicine and Susan Bagby, MD, is professor of medicine and physiology/pharmacology at Oregon Health & Science University in Portland, Oregon.