Stemming from this belief, some pregnant women of the early to mid 20th century consumed in drinking of alcohol, ingesting of medications, and smoked cigarettes.
Since Barker's initial findings, the results have been replicated in diverse populations of Europe, Asia, North American, Africa, and Australia.
Essentially, all transmissions entering the placenta act as "postcards" giving the fetus clues as to the outside world, preparing its physiology appropriately.
[2] This can be an adaptive mechanism, when fetal conditions accurately represent the world of birth; alternatively, it can be a harmful mechanism, when fetal conditions of plenitude or scarcity do not match the world of birth and the child has been physiologically predisposed to inhabit an environment where expected resources are drastically different from reality.
[citation needed] The thrifty phenotype hypothesis proposes that a low availability of nutrients during the prenatal stage followed by an improvement in nutritional availability in early childhood causes an increase risk of metabolic disorders, including Type II diabetes, as a result of permanent changes in the metabolic processing of glucose-insulin determined in utero.
[5] This predominantly affects poor communities, where maternal malnutrition may be rampant, in turn causing fetuses to be biologically programmed to expect sparse nutritional environments.
This difference between expected nutritional deficits and actual food surplus results in obesity and eventually Type II Diabetes.
[6] Janet Rich-Edwards, an epidemiologist at Harvard Medical School, initially set out to disprove the fetal origins theory with her database of over 100,000 nurses.
Instead, she found that the results hold: a strong relationship exists between low birth weight and later coronary heart disease and stroke.
[2] The same economic researcher, Douglas Almond, has investigated other historical situations affecting particular cohorts of fetuses: children born during or immediately following the Chernobyl nuclear disaster explosion, and China's Great Leap Forward (which resulted in a deadly famine).
[2] Such outcomes can have lasting impacts on the productivity and economic security of a society for an entire generation of individuals, and perhaps even continue to affect future descendants through changes in gene expression.
The metabolic nature of the children was completely different, despite being born to the same mother, supporting the idea that the gestational environment strongly influences future outcomes.
[2] In discussing the epigenetics findings of fetal origins, Princeton University's Janet Currie says, "The long-vaunted distinction between nature and nurture is therefore outdated and unhelpful.
Certain historical events provide epidemiological support for the Developmental Origins of Health and Disease, including the Dutch Hunger Winter and the Holocaust.
In a study conducted in Uganda it was concluded that exposure to the fast, early in a pregnancy effectively doubles the likelihood of a person having a cognitive disorder of some kind.
When compared to Jewish families who were living outside of affected areas of Europe, the findings continued to stand: "The gene changes in the children could only be attributed to Holocaust exposure in the parents.
Beate Ritz, a professor at UCLA, found significantly higher rates of heart malformations and valve defects in the children born to women living in highly polluted areas of Los Angeles.
Pregnant women who firsthand experienced the devastation of the World Trade Center attack on September 11, 2001 were studied to observe the effects of PTSD (post-traumatic stress disorder) on their child's future health.
Based on the findings that there was a trimester distinction in strength, conclusions can be drawn that the development of a vulnerability to stress was due at least in part to environment in utero.
Women in New Orleans at the time who reported enduring multiple severe disaster experiences also had a significantly higher chance of delivering early or low birth weight children.
[19][22] Besides birth weight, mental health, and reduced cortisol levels, effects of stress during pregnancy have also been linked to impaired cognitive development in children as seen in the maternal population exposed to a severe snowstorm in Canada.
[23] Women who experienced the most stressful storm related events had children with detriments in cognitive, language, behavioral, and attention outcomes.
Working long hours, having temporarily employment, or reporting physically demanding job tasks showed "significant and strong" associations with poorer later birth outcomes.
[2] However, some research has found that moderate amounts of stress and cortisol passed on to a developing fetus are actually beneficial, perhaps acting to give organs a "workout" prior to birth.
[2] Further cementing the theory that maternal emotional state can impact child development are the sound research findings that women who are clinically or slightly depressed during pregnancy are more likely to have children with low birth weight, putting them at risk for future health concerns of their own.
Such interventions could instead have increased negative effects,[29] until the specific mechanisms and processes are more deeply understood by which birth and early childhood weight determine development.
As stated in "Killing Me Softly: The Fetal Origins Hypothesis", "Such pre-emptive targeting would constitute a radical departure from current policies that steer nearly all healthcare resources to the sick, i.e. the "pound of cure" approach.
Because the demonstrated effects range from dramatic to subtle in the wide spread areas of educational achievement, emotional stability, career trajectory, life expectancy, disease prognosis, and psychological disorders, interventions addressing the gestational period could potentially have significant impact on individual and societal levels.