The four most common teratogens are tobacco, alcohol, medications and illegal drugs. Teratogens are substances that could harm a developing fetus by affecting growth and causing birth defects or death. The use of tobacco during pregnancy is dangerous because the smoke causes the blood vessels to constrict.
the teratogen, if it is to have any effect, will be so profound as to cause a spontaneous abortion. Some examples of teratogens known to cause human confirmation are listed in the table below. A few of the most common examples will be discussed below.
Pregnancy and Teratogens. Medically reviewed by Janine Kelbach, RNC-OB on March 4, 2016 — Written by the Healthline Editorial Team. Teratogens are drugs, chemicals, or even infections that can ...
What are the four most common teratogens? A: Quick Answer The four most common teratogens are tobacco, alcohol, medications and illegal drugs. Teratogens are substances that could harm a developing fetus by affecting growth and causing birth defects or death. Full Answer
Additionally, teratogens may also affect pregnancies and cause complications such as preterm labors, spontaneous abortions, or miscarriages. Teratogens are classified into four types: physical agents, metabolic conditions, infection, and finally, drugs and chemicals. The word teratogen originates from the Greek word for monster, teratos.
Reason low to moderate levels of a teratogen may cause no abnormalities to the embryo during the first 2 weeks of life. Still traveling down the fallopian tube to the uterus and has not, yet, embedded into the endometrial wall so there is not a connection between the maternal and fetal circulatory systems.
Start studying Chapter 6 Human Diseases. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Search. ... Tetralogy of Fallot has four congenital heart defects. What is the classic symptom of this defect either at birth or within the first several months? ... What are the most common teratogens? In any order ...
A teratogen is any agent that causes an abnormality following fetal exposure during pregnancy. Teratogens are usually discovered after an increased prevalence of a particular birth defect. For example, in the early 1960’s, a drug known as thalidomide was used to treat morning sickness. Exposure of the fetus during this early stage of development resulted in cases of phocomelia, a congenital ...
What are the most sensitive periods for teratogens in pregnancy? Once the egg is fertilized (conception), it takes about six to nine days for implantation (anchoring into the uterus) to occur. Once the fertilized egg is connected to the uterus, a common blood supply exists between the mother and the embryo.
Some teratogens are benign until they build to "threshold concentration" levels in the mother and then their effects are seen. Some teratogens are dangerous throughout a pregnancy and some are dangerous only at specific points of embryonic development. The only safe course of action is to actively avoid known teratogens before and during pregnancy.