Prenatal risk factors and postnatal central nervous system function

Abstract

Risk factors prior to birth can be subdivided according to timing, duration, dosage of exposure, and their mode of action; these variables determine which tissues/organs in the offspring are affected and to what extent. The central nervous system (CNS) as the most complex human organ is frequently affected. Sometimes exposures cause gross damage to the brain, but subtle effects due to exposures to single and frequently multiple risk factors are much more common. Multiple risk factors with small effects are difficult to unravel and trace back to their individual effect.In the preconception phase, the parental haploid genomes can harbor genetic polymorphisms and molecular genetic or chromosomal aberrations that are associated with variations in CNS functioning of the offspring. Depending on the developmental gene regulation, structural and/or functional damage to the CNS ensues pre or postnatally. The extent to which functionally relevant epigenetic alterations are transmitted via the germ lines is currently a subject of scientific debate. After conception, short or longer acting risk factors can affect brain function via diverse mechanisms including epigenetic modifications of specific genes. Drugs can cross the placenta and exert their detrimental effect by binding to the respective receptors in the developing brain; such receptors are frequently already expressed in the embryonic stage. The reduction of placental blood flow as a consequence of the exposure to specific risk factors-like alcohol, nicotine and/or cannabis use-is one example of a mechanism that may indirectly impact offspring CNS function.The prenatal period typically refers to the time from conception to birth, during which a host of maternal exposures to for example drugs, medications, toxins, infectious agents, radiation as well as maternal psychological factors can directly or indirectly influence the offspring's brain structure and/or function. Due to the rapid development from zygote to term newborn within approximately 270 days, the timing at which an embryo (first 8 weeks after conception) or fetus is exposed to nongenetic risk factors is crucial; particularly early exposure can entail substantial CNS structural aberrations or even lead to intrauterine death. Maternal malnutrition and other factors associated with poverty represent examples of risk factors, which continuously impinge on the embryo/fetus. Unfortunately, it is not uncommon for multiple risk factors (genetic and non-genetic) to be present at the same time. Thus, pregnant women who drink alcohol frequently also smoke; their genetic makeup and social environment predispose them to stress, depression, violence and poor nutrition both prior to and during pregnancy. Such interrelated exposures to a range of risk factors entail serious methodological problems for determining the effects of any single factor; this is even more so the case, because the same risk factors can remain operative postnatally. According to the dual hit hypothesis, a risk factor during intrauterine developmen...

Aktueller Stand und zukünftige Entwicklung der prä- und postnatalen Vorsorge- bzw. Screeninguntersuchungen – Evidenz tut Not

“…Interdisziplinäre Kooperation Bei den Mutterschafts-und Kinderrichtlinien erschiene eine wechselseitige Bezugnahme hilfreich. Die Bedeutung pränataler Risikofaktoren für eine gesunde körperliche und seelische Entwicklung wird zunehmend evident [31]; umso wichtiger ist es, den Brückenschlag zwischen der Prä-und Postnatalperiode bestmöglich zu gestalten. Kinder-und Jugendmediziner und -psychiater und Gynäkologen sollten an Überarbeitungen der Mutterschafts-bzw.…”

Neuropsychological analysis of the features of mental development in school age children with mild perinatal hypoxic damage of the nervous system in their anamnesis

“…In the medical literature there are descriptions of a number of studies (Naeye & Peters, 1987;Salova, 2009;Calvigioni & Hurd, 2014;El Marroun, White, Verhulst, & Tiemeier, 2014;Hebebrand & Verhulst, 2014;Sayal, Heron, Draper, Alati, Lewis, Fraser,…, & Gray, 2014;Tiesler & Heinrich, 2014), proving the negative impact of intrauterine hypoxia, including of toxic origin, on the child's mental ontogenesis, even in cases of favorable outcome. Medical research cannot replace the psychological study of the issue.…”