Correlations fetal environment

What all these technical details mean for us can be briefly stated in plain English We know enough about the detailed development of the human brain to expect it to be highly vulnerable to impacts on the fetal environment. Neuroscientists are not surprised by correlations between impacts on the fetal environment and later behavior and cognitive performance. The purpose of this chapter has been to explain this lack of surprise. 

The most important general idea about the fetal environment is that any impact that results in physiological stress for the fetus can be a risk factor for adverse developmental and health outcomes. This is clear only from animal experiments. For humans, on whom comparable experiments are not possible, we must depend on empirical data, on correlations, and on deductions. Moreover, because the physiology, chemistry, hormone profile, and so on of the embryo and fetus are continually changing during gestation, the developmental consequences of an environmental impact depend on when it occurs, and on its duration, severity, and type. 

Definitely not. The similar environments in these studies is the postnatal environment. The prenatal environment is never considered in the analysis. For twins reared in similar postnatal environments, we don t know if the higher twin-pair IQ correlations for MZ twins are due to identity of genes or similarity of fetal environments. It is certainly possible that the fetal environments (including reactions to impacts) of identical twins are always more similar than the fetal environments of fraternal twins. We don t know enough yet about human twin biology to discount that possibility. 

Washino N, Saijo Y, Sasaki S, Kato S, Ban S, Konishi K, Ito R, Nakata A, Iwasaki Y, Saito K, Nakazawa H, Kishi R (2009) Correlations between prenatal exposure to perfluorinated chemicals and reduced fetal growth. Environ Health Perspect 117 660-667... 

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