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Teratogen

Any agent or stubstanch which can cause developmental abnormalities in the embryo or fetus

Teratogenicity

Capabiity of causing develomental abnormality

Types of teratogens

Pharmaceuticals
Alcohol
Smoking
Illegal drugs
Infection
Radiation
Maternal disease

Possible effects of a teratogen

No appaarent consequence
Altered growth
Abnormal growth in an organ system
Carcinogenesis
Embryonic/fetal death

Most notorious teratogen

Thalidomide

Thalidomide

Drug that was first invented and marketed as a sleeping pill and later prescribed topreven miscarriage. It was widely distribued in Europe and Australia

Abnormalities caused by thalidomide

Almost complete absence of limb development. Humerus/radius/ulna severely shortened and hands almost directly attached to shoulder joint

Drug that led to the passage of the FDA Pure Food and Drug Act of 1962

Thalidomide

Current drugs with known teratogenicity

Accutane
Tetracycline
Coumadin
Anti-depressants

Accutane

A vitamin A derivative used totreatesevere acne

Tetracycline

Antibiotic

Coumadin

Drug that inhibits or prevents clotting

Fetal alcohol syndrome (FAS)

General term for the collective disorders caused by alcohol consumption during pregnancy.

Clinical signs of FAS

Slowed growth
Mild to severe devoleopmental delays
Behavioral disturbances
Craniofacial abnormalities (eg, microecephaly and visual impairments)
Eyes may fail to develop (severe cases)

Direct effect of smoking during pregnancy

Oxygen delivery to embryo/fetus reduced

Reason oxygen delivered to embryo is reduced when mother smokes during pregnancy

The carbon monoxide in the smoke binds to the iron in hemoglobin ~300 times more strongly than oxygen

Increased risks to the baby from smoking during pregnancy

Miscarriages (spontaneous abortions)
Pre-term babies
Low birth weight
SIDS (sudden infant death syndrome)

Increased risks to mother from smoking during pregnancy

Abruptio placentae
Placenta previa

Abruptio placentae

Premature separation of the placenta from the wall of the uterus. This causes severe hemorrhage to both mother and fetus

Placenta previa

Abnormal placement of the placenta: Dangerously close to cervix or may completely overlap cervix

Optimal placement of placenta

Upper uterine wall

Risk of placenta close to or overlapping the cervix

Hemorraging

Effects to newborns from mothers smoking marijuana during pregnancy

Tremors
Increased startle reflex

Effects to mothers from using cocaine during pregancy

Vasoconstriction of the uterine smooth muscle

Risks from vasoconstriction of the uterine smooth muscle during pregnancy

Miscarriage
Abruptio placentae
Intrauterine growth retardation
Pre-term birth

Effects to newborns from mothers using cocaine during pregancy

Addiction to cocaine

Consequence of newborns born to mothers that used cocaine or herion during pregnancy

Brain damage
Various neurobehavioral abnormalities

Effects of microbes that infect embryos/fetuses

Micarriage
Premature birth
Congential defects
Growth retardation

Microbes most likely to harm embryos/fetuses in the US

Syphilis
Toxoplamosis
O
Rubella
Cytomegalovirus
Herpes simplex
Measels
Mumps

Effects of ionizing radiation to individuals

Damage to the genetic material of the individual

Ionizing radiation

Very high energy radiation

Types of ionizing radiation

X-rays
Gamma rays

Possible effect of high doses of ionizing radiation to embryos, fetuses, and newborns

Death

Possible effects of lower doses of ionizing radiation on developing babies

Congenital abnormalities
Growth retardation

Effects of radiation during embryonic and fetal development

Increased incidence of cancer during later life

Population that has a greater than normal incidence of childhood and other cancers

Survivors of radiation exposure

Reason ultraviolet radiation is not teratogenic

Does not possess enough energy

Effects of ultraviolet radiation

Sunburn and possible skin cancer for mother, not embryo/fetus

Diseases and conditions of the mother that could affect the developing embryo/fetus

Diabetes mellitus
Anemia
Heart disease
Vitamine deficiency

Most important vitamin for the embryo

Folic acid/folate

Folic acid/folate

Cofactor for DNA synthesis

Risk of folic acid/folate deficiency of mother on the baby

Neural tube defects

Effects of a neural tube that does not close

Spina bifida
Anecephaly
Menogocoele

Spina bifida

Spinal column doesn't close

Anecephaly

Embryo's brain fails to develop

Menigocoele

Meninges protrude from the skin

Period of pregnancy in which exposure to a teratogen is much less damaging

Very early or very late

Possible consequences of exposure to a teratogen during critical periods

Harm or kill embryo/fetus

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

Impact of high levels of teratogen often before the mother realizes she is pregnant

Prenatal death

Embryonic development during weeks 2-5 of pregnancy

Rapid development of central nervous and circulatory systems. Development of eye and limb buds

Impact of teratogens during weeks 2-5 of pregnancy

Major structural abnormalities and/or death

Systems and organs effected by teratogens during weeks 4-7 of pregnancy

Nervous system
Heart
Eyes
Ears
Limbs
Mouth/teeth

Systems and organs effected by teratogens during weeks 6-10 of pregnancy

CNS
Heart
Special senses
Limbs
Digestive system

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