londonchinatown.org Bookshelf. A organization of the nationwide Library of Medicine, nationwide Institutes that Health.
You are watching: Which of the following statements is true regarding the impact of teratogens?
Genetic Alliance; ar of Columbia department of Health. Knowledge Genetics: A district of Columbia guide for Patients and also Health Professionals. Washington (DC): genetic Alliance; 2010 Feb 17.
Understanding Genetics: A district of Columbia overview for Patients and Health Professionals.Show details
A teratogen is any agent that causes an abnormality following fetal exposure duringpregnancy. Teratogens are usually uncovered after an enhanced prevalence that a particularbirth defect. For example, in the early on 1960’s, a drug well-known as thalidomide to be usedto treat morning sickness. Exposure the the fetus during this early on stage of developmentresulted in instances of phocomelia, a congenital malformation in which the hands and feet areattached to abbreviated arms and also legs.
Teratogens can additionally be uncovered at house or the workplace. The result is associated to kind ofagent, dose and duration and also time of exposure. The very first half of pregnant is the mostvulnerable. Teratogenic agents include infectious agents (rubella, cytomegalovirus,varicella, herpes simplex, toxoplasma, syphilis, etc.); physics agents (ionizing agents,hyperthermia); maternal health components (diabetes, maternal PKU); ecological chemicals(organic mercury compounds, polychlorinated biphenyl or PCB, herbicides and also industrialsolvents); and drugs (prescription, over- the-counter, or recreational). In general, ifmedication is required, the lowest dose possible should be offered and mix drugtherapies and an initial trimester exposures need to be avoided.
The species or severity of abnormalities brought about by a teratogenic agent is additionally dependent ~ above thegenetic susceptibilities carried by the mother and fetus. Because that example, sports in maternalmetabolism that a certain drug will identify what metabolites the fetus is exposed to andthe expression of exposure. The genetic susceptibility that the fetus come a particularteratogenic certified dealer will likewise have an result on the last outcome.
Two the the leading preventable reasons of birth defects and also developmental disabilities arealcohol and smoking. Alcohol use in pregnancy has far-ranging effects top top the fetus and also thebaby. Alcohol can pass from the mother’s blood stream with the placenta to thefetus. Because alcohol is damaged down an ext slowly in a fetus 보다 in an adult, alcohol levelstend to continue to be high and also stay in the baby’s body longer. Bear defects associatedwith prenatal exposure to alcohol can occur in the an initial three to eight main of pregnancy,before a woman even knows the she is pregnant.
Fetal alcohol syndrome is a group of abnormalities in babies born to mothers who consumealcohol during pregnancy. It is the most common known non-genetic (non-inherited) reason ofmental retardation in the U.S. Number of educational materials in English and also Spanish areavailable from the CDC at http://www.cdc.gov/ncbddd/fas/faspub.htm.
In 2001, the approximated prevalence that smoking during pregnancy for every U.S. Women was 11.4%,ranging from 3.9% in DC come 26.2% in West Virginia. Smoking almost doubles a woman’srisk of having actually a short birth-weight baby as a an outcome of poor growth prior to birth, pretermdelivery or a combination of both. Premature and low birth-weight babies challenge an increasedrisk of significant health problems during the child period, chronic lifelong disabilities(e.g., cerebral palsy, psychological retardation) and possibly death. An ext recent research studies havesuggested a feasible link between prenatal smoking exposure and behavioral difficulties in laterchildhood and adolescence.
See more: Servants/Peasant: Medieval Engineers Servants /Peasant: Medievalengineers
In addition, virtually three percent of pregnant women usage illicit medicine such together marijuana,cocaine, Ecstasy and other amphetamines, and also heroin. These drugs can cause low birth-weight,withdrawal symptoms, bear defects, or learning or behavioral problems.