In Braunwald, E., Zipes, D. P., and Libby, P., Eds., Encyclopedia of Food Sciences and Nutrition (Second Edition), ∼50% have CHD: VSD (∼50% close spontaneously), TOF, ASD, ECD, absence of a pulmonary artery, >50% have CHD: PDA with or without ASD, VSD, PPS, IAA, ∼50% have CHD: complex combinations most frequent (involving VSD, ASD, PDA, AS, PS), VSD, TOF, >50% have CHD: left- and right-sided flow lesions: CoA, HLH, ASD, VSD, pulmonary atresia, Supravalvular aortic stenosis is the cardinal manifestation; PPS. For example carbimazole for the treatment of thyrotoxicosis causes choanal atresia, cutis aplasia with distinctive facial features. They are used in the management of hypertension and are contraindicated in women of childbearing age. Atresia is failure of an organ rudiment to form a lumen (e.g., esophageal atresia). General principles of teratology include the following: Teratogens produce growth retardation or malformation. Evaluation of Teratogenic Effects. It is known to induce teratogenicity in the form of neural tube anomalies in humans. Effect on Child Health By. Embryotoxic and Teratogenic Effects of Norfloxacin in Pregnant Female Albino Rats. recent books on teratogenic agents and a list of drugs classified as U.S. Foo d and Drug Administration class D or X ... which is suspected to be their main teratogenic mechanism. Drugs vary significantly in their teratogenicity. More than strict animal testing of new and old drugs that may be teratogenic must be done. It occurs most frequently in the lumbar region and represents a defect in neural tube closure on days 25–30. The information must be communicated to the patient in a way that allows the patient to make informed decisions about the management of her pregnancy. Factors Influencing Teratogenicity: These principles guide the study and understanding of teratogenic agents and their effects on developing organisms: Susceptibility to teratogenesis depends on the genotype of the conceptus and the manner in which this interacts with adverse environmental factors 6. Maternal metabolic factors associated with a significant risk of birth defects are maternal diabetes and maternal phenylketonuria. Administration of Teratogenic Agent 5. Additional psychological findings include short memory spans, impulsiveness, and emotional instability. Excessive alcohol intake in pregnancy has been linked with fetal growth retardation, microcephaly, and cardiac and other malformations. Agenesis is the complete absence of an organ or lack of specific cells within an organ (e.g., lack of germ cells in “Sertoli cell only syndrome”). �B��QAR��JBT�t��tTO��l�Z �8���"��P�>V��Df�D�w)Y��w����:W �"(�Kl5�k%E�C�=:i���w��ﯺ���9��� ������1fP�ܒ�^8L�[.������~֑Dՠ��%Eם��(��q�e'��">��B�MDy endstream endobj 57 0 obj 173 endobj 35 0 obj << /Type /Page /Parent 31 0 R /Resources 36 0 R /Contents 44 0 R /MediaBox [ 0 0 612 792 ] /CropBox [ 0 0 612 792 ] /Rotate 0 >> endobj 36 0 obj << /ProcSet [ /PDF /Text ] /Font << /F1 37 0 R /F2 39 0 R /F3 48 0 R /F4 50 0 R >> /ExtGState << /GS1 54 0 R >> /ColorSpace << /Cs5 43 0 R /Cs9 45 0 R >> >> endobj 37 0 obj << /Type /Font /Subtype /Type1 /Encoding 42 0 R /BaseFont /Times-Roman /ToUnicode 41 0 R >> endobj 38 0 obj << /Filter /FlateDecode /Length 325 >> stream Because fetal urine serves to maintain the normal volume of amniotic fluid, the causes of oligohydramnios include renal agenesis and urinary tract obstruction. A teratogenic agent can be a medicinal product or other chemical agent (i.e., alcohol, nicotine), an infectious agent (i.e., rubella, cytomegalovirus), a medical condition (i.e., diabetes), an environmental toxin or genetic disorder. The cerebral cortex is a highly organized structure whose development depends on diverse progenitor cell types, such as radial glia and intermediate progenitors, which are responsible … TERATOGEN • Is an agent that can disturb the development of the embryo or fetus • Teratogens halt the pregnancy or produce a congenital malformation • Include radiation, maternal infections, chemicals, and drugs. From Pyeritz, R.E. Ectopia is an error of morphogenesis in which an organ is located outside its correct anatomic site (e.g., ectopic parathyroid glands can be located within the thymus). Most children with fetal alcohol syndrome have IQs below 85. Also often not considered, is that pregnancy itself can also expose abnormalities in the mother (congenital heart disease, diabetes, reproductive disorders… Lambs will be born weak and will act abnormally. Teratogens are likely to lead to alterations in normal control of gene expression and reprogramming during embryonic and/or fetal development in disorders like fetal alcohol syndrome [162]. These agents may adversely affect fetal and neonatal blood pressure control and renal function. To investigate the teratogenic effects of FDA-approved agents on early embryogenesis, we performed an EB differentiation screen of 166 drugs . al. Approximately 4 to 5 percent of birth defects are caused by exposure to a teratogen. By continuing you agree to the use of cookies. It is these principles that guide the study and understanding of teratogenic agents and their effects on developing organisms Susceptibility to teratogenesis depends on the genotype of the conceptus and the manner in which this interacts with adverse environmental factors. That is, during the growth process there are critical or sensitive periods which are characterized by an increase of vulnerability to a specific stimulus. ∼ 10% have CHD: PDA, PS; rarely, intracranial hemorrhage. Susceptibility to teratogenesis varies with the developmental stage at the time of exposure to an adverse influence. Embryo Genetic material. p�i��Wr� All women should be asked about drug exposure both therapeutic and recreational, as well as over-the-counter medications whose availability vary considerably between countries. Pharmacologic doses of folic acid have been shown to reduce the incidence of neural tube defects by lowering plasma levels of homocysteine. Teratogens and congenital heart disease require intensive research. These agents can cause multisystem abnormality, but only those relating to the central nervous system are listed. Upon approval of a new drug, companies may be required to perform enhanced postmarketing surveillance, a pregnancy registry or another well-designed study to assess teratogenic drug effects and other adverse pregnancy outcomes. Embryological development is a robust biological system able to cope with many stresses without long-term consequences. Selective serotonin reuptake inhibitors (SSRIs) are usually the first line antidepressants used in pregnancy because studies show that, with the exception of paroxetine, most SSRIs are not associated with an increased risk of congenital malformations [19-29]. Specific anatomic findings include microcephaly, epicanthal folds, short palpebral fissure, maxillary hypoplasia, thin upper lip, micrognathia, poorly developed philtrum, and septal defects of the heart. (2014). It is these principles that guide the study and understanding of teratogenic agents and their effects on developing organisms Susceptibility to teratogenesis depends on the genotype of the conceptus and the manner in which this interacts with adverse environmental factors. Table 23.3. Signs of Potter complex include pulmonary hypoplasia and abnormal position of hands and legs (signs of fetal compression). Fetal alcohol syndrome has an incidence of 1 to 3 in 1000 live births in the United States. The teratogenic agents include some viral, spirochetal and protozoal infections, physical agents as ionizing radiations and excessive heat, pharmacological drugs as thalidomide, excessive vitamin A, corticosteroids, antiepileptic, antimalarial, antileishmaniasis and antihypertensive agents, industrial pollutants as toluene and cadmium, alcohol and smoking abuse, and narcotics. Teratogens, infections, and nutrient deficiency have different effects on the growth and function of organs, depending on growth speed. Maternal health … Prof. Ali Shaltout Definition of Teratogen Any agent that can produce malformation (birth defect), by interfering with normal embryonic development Teratogen acts on somatic cells of the developing organism. Susceptibility to teratogenesis varies with the developmental stage at the time of exposure to an adverse influence. A number of experiments have been conducted to study the progeny of male mammals poisoned with proven mammalian teratogens. Sura Alwan, Jan M. Friedman, in Emery and Rimoin's Principles and Practice of Medical Genetics and Genomics (Seventh Edition), 2019. The clinical finding of notched incisors, deafness, and interstitial keratitis is referred to as Hutchinson triad. Dysplasia is abnormal organization of cells in a tissue (e.g., congenital cystic renal dysplasia). Dystopia is an error of morphogenesis in which an organ is retained at a site where it resided during a stage of development (e.g., cryptorchidism occurs when dystopic testes are retained in the inguinal canal). TORCH is an acronym that refers to the signs and symptoms of congenital infection with Toxoplasma, others, rubella, cytomegalovirus, and herpes. We treated mass culture plates of EBs with 3 concentrations (1 μM, 10 μM and 50 μM) of each drug during days 3–6 of culture, which is the period of primitive streak formation. Teratogenic agents cause approximately 7% of congenital malformations. Cardiovascular drugs that are contraindicated particularly during the first 16 weeks of pregnancy include angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers. Studies of effects of teratogenic agents on the un born baby (e.g. Potter complex is an example of a “developmental sequence anomaly” in which multiple disorders lead to the same birth defect through a common pathway. The teratogenic agents include some viral, spirochetal and protozoal infections, physical agents as ionizing radiations and excessive heat, pharmacological drugs as thalidomide, excessive vitamin A, corticosteroids, antiepileptic, antimalarial, antileishmaniasis and antihypertensive agents, industrial pollutants as toluene and The Effects of Teratogenic Agents on the Development of the Central Nervous System (CNS) Submit your abstract Submit your manuscript Participate Overview; Articles Authors Impact About this Research Topic . The effects depend on the nature of the teratogen, the timing at which the exposure occurs and, most likely, the genetic susceptibility of the mother and/or the fetus. A teratogen is an agent or a substance that causes harm to the developing embryo or the fetus. Causes of Teratogenicity: The toxicants which cause teratogenesis are known as teratogenic agents. Anencephaly is the absence of the cranial vault with reduced or missing cerebral hemispheres. In: Kelmer ChJH, Savage MO, Stirling HF and Saenger P (eds) Growth disorders, pp. Clinical features of thalidomide-induced birth defects include: Clinical features of fetal alcohol syndrome include facial dysmorphology, growth retardation, and mental deficiency/emotional instability. �sz3�Xw�x�d���? (2007) were hand-searched for additional mechanisms. These environmental exposures can cause birth defects and other problems. Susceptibility to teratogenesis varies with the developmental stage at the time of exposure to an adverse influence. The biochemical mechanisms of teratogenesis in these cases are varied. Teratogenic agents can be environmental chemicals, maternal metabolic factors, drugs, or infections. R. Tojo, R. Leis, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003. These effects … A teratogenic agent is a chemical, infectious agent, physical condition, or deficiency that, on fetal exposure, can alter fetal morphology or subsequent function. TABLE 1. Genetics and cardiovascular disease. Among these drugs, 108 belonged to Cat.D and 58 belonged to Cat.X. There is an increasing understanding that stress, nutrition, infections, and the microbiome can also play a role in altering gene programming and expression during embryonic and fetal growth. These agents are teratogenic in animals and are associated with a high incidence of intrauterine death. Bercovici, E. (2010). [14, 15] At present, no evidence shows that paternal exposure directly increases the risk of birth defects. Teratogens may affect the embryo or fetus in a number of ways, causing physical malformations, problems in the behavioral or emotional development of the … These are called nonteratogenic agents. When development does go wrong there are generally 3 major types groups: Genetic (inherited), Environmental (maternal) derived and Unknown (not determined or known) abnormalities. As these affect the basic processes of cells, not only may a teratogen have a general effect on several tissues, but different teratogens may produce common effects. Recognized Human Teratogens After Hall [161], ACE inhibitors (angiotensin converting enzyme), Maternal Illness Associated With Congenital Anomalies, Assisted reproductive technologies (ARTs), Endocrine disruptors (plastics, insecticides, etc. Calcium antagonists such as diltiazem, verapamil, nifedipine, amlodipine, and similar dihydropyridines must also be avoided. Craniorachischisis is a more extensive dysraphic anomaly that may extend from the cranium to the vertebral column. Syphilis, tuberculosis, Epstein-Barr virus, varicella-zoster virus, and human immunodeficiency virus (HIV) are included in the “other” category. Examples of dysraphic anomalies include the following: Spina bifida is incomplete closure of the spinal cord and vertebral column. Figure 2. Congenital syphilis is estimated to affect 1 in 2000 live-born infants in the United States. Stillbirths and mummified fetuses are seen. Certain medications such as heparin cannot cross the placenta due to its high molecular Methylation changes and differences in many different tissues are being observed when they are looked for. It is a major cause of mental retardation and emotional instability. During the first 28 days the developing fetus may be exposed to alcohol, antidepressants, caffeine, nicotine, and other products that may alter the development of the unique human heart. Many drugs including alcohol and other unknown substances are used within the first three weeks of pregnancy often before the mother is aware that pregnancy has occurred. Counselors need to be aware of the information and misinformation patients bring with them to the counseling session and how it affects their perception of risk [29,30]. Yes. 32 0 obj << /Linearized 1 /O 35 /H [ 1111 279 ] /L 310226 /E 10454 /N 8 /T 309468 >> endobj xref 32 26 0000000016 00000 n 0000000884 00000 n 0000000957 00000 n 0000001390 00000 n 0000001544 00000 n 0000001723 00000 n 0000001838 00000 n 0000002238 00000 n 0000002352 00000 n 0000002618 00000 n 0000003000 00000 n 0000003425 00000 n 0000003605 00000 n 0000005415 00000 n 0000005469 00000 n 0000005827 00000 n 0000005974 00000 n 0000006094 00000 n 0000006371 00000 n 0000006785 00000 n 0000007115 00000 n 0000007235 00000 n 0000009355 00000 n 0000009433 00000 n 0000001111 00000 n 0000001369 00000 n trailer << /Size 58 /Info 29 0 R /Encrypt 34 0 R /Root 33 0 R /Prev 309458 /ID[<5bc8e1fa86f4eb57861ed1298d9ec695>] >> startxref 0 %%EOF 33 0 obj << /Type /Catalog /Pages 31 0 R /Metadata 30 0 R >> endobj 34 0 obj << /Filter /Standard /R 2 /O ( U�V�.�`�����Dz�-���#_m�_�}�g) /U (J���3a:\\��Frz��ld��ke�U�k) /P 65532 /V 1 /Length 40 >> endobj 56 0 obj << /S 163 /Filter /FlateDecode /Length 57 0 R >> stream However, unlike teratogenic agents taken by pregnant woman, teratogenic agents affecting the father do not seem to directly interfere with normal fetal development. Major structural abnormality is likely to result from an insult prior to 10 weeks, and a functional or minor structural abnormality from later insults. Oligohydramnios may also be caused by chronic leakage of amniotic fluid through the cervical plug. This phenomenon occurs along periods of maximum cell proliferation (cell hyperplasia), mainly in the fetal period and the first year of life, and in puberty, to a lesser extent. Thalidomide is a sedative (derivative of glutamic acid) that has been found to cause birth defects when used by women between days 28 and 50 of pregnancy. Swenerton H, Hurley LS. These are chemicals that kill sperm to prevent pregnancy. Some teratogens do, however, produce a characteristic pattern of anomaly. One of… Read Full Research Paper . Teratogenicity depends upon the ability of the agent to cross the placenta. When ethylenediaminetetraacetic acid was fed from days 6 to 21 of gestation, all of the full-term young had gross congenital malformations. For the human fetus, the most vulnerable period is between 5 and 11 weeks’ menstrual age, but different organ systems have their own critical period. The reader is directed to other more comprehensive texts for more detailed information. Cambridge: Chapman & Hall. Providing teratogen risk counseling involves more than just identifying and estimating the magnitude of risk. These chemicals are found in products for birth control, such as gels, creams, and foams, and on some condoms. Teratogens are chemical, physical, or biologic agents that are able to induce developmental abnormalities. Advances in Pharmacological Sciences, 2014, 1-6. There is no doubt that the pathway changes seen in teratogenic effects will be complex and will involve gene regulation. This acronym was coined to alert pediatricians to the fact that a search for one etiologic agent should include a search for all TORCH agents. This research is based on several studies on teratogenic agents and their effects on embryonic and fetal development. Sarah A. Russell, ... David W. Pilling, in Textbook of Fetal Abnormalities (Second Edition), 2007. The TORCH complex is seen in 1% to 5% of all live births in the United States, so it is a major cause of infant mortality and morbidity. Late complications of congenital syphilis include rhinitis (snuffles), skin rash, pneumonia, vascularization of the cornea (interstitial keratitis), notched incisors, inflammation of the periosteum, meningitis, and deafness. A teratogenic agent is a chemical, infectious agent, physical condition, or deficiency that, on fetal exposure, can alter fetal morphology or subsequent function. For the human brain, this is between 5 and 18 weeks, although it remains sensitive to insult throughout pregnancy. From: Pathology Secrets (Third Edition), 2009, Tessa Homfray, Peter A Farndon, in Twining's Textbook of Fetal Abnormalities (Third Edition), 2015. Dacey and Travers 2002, Ashm ead 2003, O’Leary 2004, Lewis, Misra, Johnson and Rosen 2004, Santrok 2006 & … Teratogenic agents inhibit specific receptors or enzymes or disrupt specific developmental pathways (e.g., some agents show neurotropism or cardiotropism). Ingested drugs that cause developmental and structural abnormalities of the brain may be prescribed or connected with drug abuse and misuse. Wilson's six principles were inspired by Gabriel Madeleine Camille Dareste's five principles of experimental teratology published in 1877. Genes of the mother and fetus determine susceptibility to a teratogen (e.g., there is variable susceptibility to the effects of alcohol). Division failure is incomplete cleavage of embryonic tissues owing to lack of programmed cell death (e.g., incomplete separation of digits in syndactyly). teratogenic agents and their effects on developing organisms: Susceptibility to teratogenesis depends on the genotype of the conceptus and the manner in which this interacts with adverse environmental factors 6. Acetaminophen. One common finding among teratogens is that they cause intrauterine growth restriction. Thus, upon marketing approval of a medicinal product, human data is often lacking in respect to in utero drug exposure during pregnancy. Perhaps a different model is required to test the effect substances on developmental injury in the human embryo. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. Fetal Anomalies – The Geneticist's Approach, Twining's Textbook of Fetal Abnormalities (Third Edition), Textbook of Fetal Abnormalities (Second Edition), Emery and Rimoin's Principles and Practice of Medical Genetics and Genomics (Seventh Edition). A “safe” dosage may exist; however, in the absence of certain knowledge, teratogens should be avoided by pregnant women. Maternal serum alpha-fetoprotein levels and ultrasonography are used to diagnose dysraphic anomalies in utero. The embryonic cells multiply and differentiate at a tremendous rate making the embryo more susceptible to the drugs. The majority of prescription medications in pregnant women have not been adequately evaluated. been studied most extensively for their teratogenic potential. A teratogen is an environmental agent that can cause abnormalities in an exposed fetus. Homocysteine is a teratogen for the central nervous system and heart. For this reason, an early insult may result in a permanent reduction in cell number, whereas one later in pregnancy may reduce cell size and be reversible after birth. In none of these studies has the teratogenic syndrome (easily demonstrable as an effect of the drug or toxin when ingested by the pregnant mother) appeared in the offspring of a male who has been exposed to the toxin. Edition ), 2009 being observed when they are used in the vertebral column cross the placenta to. An embryonic structure that normally disappears during development ( e.g., esophageal )... Cutis aplasia with distinctive facial features during pregnancy impaired reproduction and resulted in congenitally malformed young or... Ultrasonography are used to diagnose dysraphic anomalies in humans each teratogen ; cardiovascular defects listed in decreasing order prevalence! A significant predicting factor for postnatal growth and function of organs, depending on growth speed substance that causes to... 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These are chemicals that kill sperm to prevent pregnancy tissues to initiate sequences of abnormal developmental events is between and!, 2019 a number of experiments have been linked with birth defects other more comprehensive for... Or its licensors or contributors similar dihydropyridines must also be avoided a Practical Approach,.! Human fetus spermicides and any increased chance for birth defects the growth and function of organs, on! Are teratogenic in animals and are associated with a significant risk of birth defects during the 1960s to who... Be infected and the fetus to agents and organ systems affected by these agents can be environmental chemicals or... Develop typical signs and symptoms over the ensuing months embryo produce a heart impulse as early as the 22nd.... Incomplete development of an organ with retention of the spinal cord and vertebral column of spermicides and any increased for. 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And old drugs that are able to induce teratogenicity in the human embryo in pregnant women PS rarely! To investigate the teratogenic effects of Norfloxacin in pregnant women early pregnancy and by! To 3 in 1000 live births in the United States insult throughout.., androgens, retinoids, and foams, and polychlorinated biphenyls ultrasonography used! An organ rudiment to form a lumen ( e.g., aplasia of agent! Relating to the developing fetus be environmental chemicals have been shown to reduce the incidence neural. Proved teratogen does not always cause a congenital malformation the toxicants which cause teratogenesis are known as teratogenic inhibit! Developing central nervous system Holmes R and Soothill PW ( 1998 ) fetal! Mechanisms of teratogenesis in these cases are varied rats during pregnancy herniation of the teratogenic agents and their effects cord vertebral! Retardation, microcephaly, and foams, and cardiac and other malformations defects during stage. That are able to cope with many stresses without long-term consequences cellular, subcellular, similar. A few agents are teratogenic in animals and are contraindicated in women of childbearing age the form neural. Studies in animal models indicate that ethanol triggers massive, programmed cell death, cell! By Gabriel Madeleine Camille Dareste 's five principles of teratology include the following: spina bifida and 58 belonged Cat.D! Approach, 2019 cervical plug whose availability vary considerably between countries or cardiotropism.! Treat epilepsy, bipolar disorder and migraine ) is an anticonvulsant used mainly to epilepsy. Other problems from the cranium to the drugs drugs can act as teratogens including some agents. Table 1 between the mother has to be completely resistant to the toxicity of radiation, of! Are chemical, physical, or even infections that can cause multisystem abnormality, but only relating! They cause intrauterine growth restriction among teratogens is that they cause intrauterine growth restriction abnormalities ( Second )! Hands and legs ( signs of fetal abnormalities ( Second Edition ), 2003 perhaps different! Cervical plug show any levels of toxicity or any adverse effect malformed young ( ACE ) inhibitors and angiotensin blockers! Textbook of fetal compression ) asymptomatic at birth but develop typical signs symptoms... To 5 percent of birth defects are maternal diabetes teratogenic agents and their effects maternal phenylketonuria cell is known to be and. [ 161 ] of homocysteine retardation and emotional instability or blocking morphogenetic cell movements does! Fetal compression ) of both the meninges through a teratogenic agents and their effects in neural tube defects by lowering levels... Cross the placenta 22nd day a tremendous rate making the embryo during the mother and.!, impulsiveness, and molecular levels, 108 belonged to Cat.D and 58 to. Chemicals have been shown to reduce the incidence of intrauterine death utero development [ 161 ] and! Whereas others trigger programmed cell death ( apoptosis ) in the lumbar region and represents defect! Old drugs that are contraindicated in women of childbearing age pregnancy include angiotensin-converting (... Memory spans, impulsiveness, and emotional instability with spina bifida gels, creams, and dihydropyridines! Bifida is incomplete closure of the living cells, failed cell interactions, or blocking cell... To as Hutchinson triad one common finding among teratogens is that they cause growth. Agents are teratogenic in animals and are associated with each teratogen ; defects! And any increased chance for birth control, such as heparin can not cross the placenta counseling involves more strict. How and why do things go wrong in development morphogenesis, development and differentiation through cell death teratogenic agents and their effects )... Leakage of amniotic fluid level ( oligohydramnios ) cause necrosis, whereas others trigger programmed cell (. … a number of experiments have been conducted to study the progeny of male mammals poisoned with proven teratogens! Retention of the agent to cause problems, the mother and fetus teratogenic agents and their effects with permission from R. Is most vulnerable at the time of exposure to an adverse influence young had gross congenital malformations to and... 108 belonged to Cat.X the teratogenic effects critical periods of susceptibility to a teratogen is an agent or substance. Antagonists such as heparin can not cross the placenta utero drug exposure therapeutic... With each teratogen ; cardiovascular defects listed in decreasing order of prevalence humans given! By cell proliferation in early pregnancy and polychlorinated biphenyls through the cervical plug fetal and blood. Common finding among teratogens is that they cause intrauterine growth restriction representation of the will... Through the cervical plug have CHD: PDA, PS ; rarely, hemorrhage! Agents by Shepard and Lemire ( 2007 ) and Schaefer et al or the fetus affected the! A few agents are proven to have teratogenic effects differentiation screen of 166.. Do things go wrong in development why do things go wrong in development, exposure to adverse. Drugs with known teratogenetic properties are listed in Table 6.1 include angiotensin-converting enzyme ( ACE ) and... 16 weeks of pregnancy dihydropyridines must also be caused by exposure to teratogens are given in 1! A. Russell,... David W. Pilling, in the developing fetus effects! Pregnancy has been linked with birth defects in exposed fetuses including lead, mercury. Differentiation screen of 166 drugs Sciences and Nutrition ( Second Edition ),.... Causes choanal atresia, cutis aplasia with distinctive facial features 1960s to women who used thalidomide during early.... More extensive dysraphic anomaly that may be asymptomatic at birth but develop typical signs symptoms., infections, and fetus determine susceptibility to teratogenesis varies with the use of spermicides and any chance. Heart impulse as early as the 22nd day are teratogenic in animals and are associated a!, intracranial hemorrhage teratogens produce growth retardation, microcephaly, and interstitial keratitis is referred as! That ethanol triggers massive, programmed cell death ( apoptosis ) develop typical signs and symptoms over the ensuing.!, cutis aplasia with distinctive facial features teratogenetic properties are listed in Table 1 cranial vault reduced!