explain the pre Natal and post natal factors the affect the human development
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Answer:
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.
Taken together, these considerations render a special issue of European Child and Adolescent Psychiatry devoted to current knowledge of prenatal risk factors, their effects on brain structure/function, and their behavioral and cognitive implications, timely. The issue includes a total of ten reviews and original articles for a selected number of pre-pregnancy and prenatal risk factors to illustrate their overall importance and to provide an insight into potentially underlying mechanisms:
1.
Prenatal alcohol exposure is one of the most prevalent, modifiable risk factors for physical (in particular neurological), behavioral, and cognitive problems in the offspring. In Great Britain, for example, 75 % of females reported having consumed alcohol at least once during pregnancy. The most severe effect of prenatal alcohol exposure on offspring, the fetal alcohol syndrome, was described for the first time in 1968. It has subsequently become apparent that milder forms of this disorder exist which have been termed fetal alcohol spectrum disorders. These may affect up to 2–5 % of children in developed countries. As mental health professionals, we are particularly confronted with their problems including hyperactivity, impulsivity, inattention, reduced cognitive functioning, and conduct problems; upon careful physical and psychological examinations, features can be delineated that help to distinguish these children from those with attention deficit/hyperactivity disorder and conduct disorders not related to prenatal alcohol exposure. It is currently unknown to what extent low levels of alcohol exposure in utero impinge on behavioral and cognitive functioning of a child; on the other hand, particularly maternal binge drinking entails substantial risks as a result of high blood alcohol concentrations. Polymorphisms in the offspring´s genes for alcohol dehydrogenases predispose to lower IQ as a consequence of prenatal alcohol exposure through specific gene–environment interactions. Prenatal alcohol exposure exerts its negative effects via different mechanisms which include direct effects on the offspring’s central nervous system via passage through the placenta and a reduced utero-placental blood flow [1].
2.
Furtado et al. [2] identified socio-demographic, psychological and social maternal risk factors associated with fetal alcohol spectrum disorders in their systematic literature review. Mothers of affected children tended to be older, less educated, and more frequently had relatives with alcohol use disorders. Importantly, older siblings of children with fetal alcohol spectrum disorders may also be affected. This finding stresses the need for early identification of fetal alcohol spectrum disorders to prevent prenatal alcohol exposure in subsequent pregnancies.
3.
Sayal et al. [3] studied the effects of episodic maternal binge drinking during pregnancy on both mental health and academic outcomes in offspring at age eleven in the Avon Longitudinal Study of Parents and Children. Eighty-five percent of all pregnant females resident in the Avon area with an expected delivery date between April 1991 and December 1992 agreed to participate in the study. Questionnaires filled in at gestation week 18 were used to determine maternal alcohol consumption during the first trimester; at 32 weeks of gestation more than half of the women again provided information on alcohol intake during pregnancy. At both 18 and 32 weeks the number of days during which at least four units of alcohol had been consumed over the last 4 week period were assessed. In addition, the frequency of drinking was also assessed thus allowing adjustment to determine effects of binge drinking. Child mental health was measured with the Strengths and Difficulties Questionnaire; academic outcomes were operationalized by use of standardized, age-adjusted total scores of the school examination taken during the final year at primary school. The analyses were adjusted for both maternal and offspring confounders including maternal mental health, preterm birth, and the child’s gender and birth weight.