Week 9 - Congenital Diseases and Teratogens

Questions and Answers

What is the primary effect of exposure during the pre-implantation and early embryonic stages of development?

Disruptions

Deformations

Either the conceptus is lost or non-affected cells replace and recover with no apparent effect (correct)

Malformations

What is the primary purpose of maternal AFP serum level screening?

To detect chromosomal abnormalities

To detect neural tube defects

To detect fetal growth and maturation disruptions

To detect all of the above (correct)

What is a characteristic of anencephaly?

Unable to feel pain

Blind and deaf

All of the above (correct)

Unaware of its surroundings

During which stage of development do malformations typically occur?

Late embryonic stage Signup and view all the answers

What is a failure of a space to close properly an example of?

Malformation Signup and view all the answers

What is the primary function of folic acid in preventing developmental diseases?

Preventing neural tube defects Signup and view all the answers

What is the primary difference between meningocele and myelomeningocele?

Myelomeningocele involves herniation of spinal tissue, while meningocele does not Signup and view all the answers

What is the term for the failure of an organ or body part to grow properly?

Hypoplasia Signup and view all the answers

What is the type of spina bifida that exposes nervous tissue without covering membranes?

Complete spina bifida Signup and view all the answers

What is the result of a failure of an embryologic structure to disappear properly? (MACA)

Thyroglossal duct cyst Signup and view all the answers

What is the term for a congenital defect resulting from failure of a tissue to divide?

Syndactyly Signup and view all the answers

What is the term for the congenital defect resulting from failure of a tissue or organ to form or develop properly?

All of the above Signup and view all the answers

What is the Potter Sequence an example of?

A cascade of events due to lack of amniotic fluid Signup and view all the answers

What is the primary effect of ionizing radiation on cells?

Direct change to molecules in cells Signup and view all the answers

What is the effect of irradiation before implantation?

Conceptus death Signup and view all the answers

What is Thalidomide, introduced in 1956?

A sedative that was never tested on pregnant women Signup and view all the answers

What type of radiation has been shown that normal light can affect development starting from the embryonic stage?

Nonionizing radiation Signup and view all the answers

What is the effect of irradiation during the later trimesters?

Deformation, fibrosis, miscarriage, and stillbirth Signup and view all the answers

What was thalidomide initially effective in treating? (MACA)

Coughs, colds, and headaches Signup and view all the answers

What is the recommendation for alcohol consumption during pregnancy?

No alcohol during pregnancy at all Signup and view all the answers

What is the effect of cigarette smoking during pregnancy on the fetus?

Increased risk of preterm delivery and low birth weight Signup and view all the answers

What is the main concern with the use of androgens during pregnancy?

Increased risk of birth defects and complications Signup and view all the answers

What is the effect of an absence of retinoic acid during fetal development?

Malformations affecting multiple organ systems Signup and view all the answers

What is the effect of valproic acid on the fetus?

Increased risk of malformations affecting multiple organ systems Signup and view all the answers

What is a major risk associated with tonic-clonic seizures during pregnancy?

Fetal hypoxia and ischemia Signup and view all the answers

What is a common cause of prematurity? (MACA)

Uterine abnormalities Signup and view all the answers

At what birth weight do premature babies have a 50% chance of survival?

< 1500g Signup and view all the answers

What is a characteristic of Neonatal Respiratory Distress Syndrome (NRDS)?

Lack of surfactant due to immature lungs Signup and view all the answers

What is the primary cause of death in neonates?

Prematurity and low birth weight Signup and view all the answers

What is the definition of Small for Gestational Age (SGA)?

Normal age but small weight Signup and view all the answers

What is a common complication of prematurity in the baby?

All the above Signup and view all the answers

What is the birth weight threshold for a baby to be considered Low Birth Weight?

< 2500g Signup and view all the answers

During which stage of development do disruptions typically occur?

Fetal stage Signup and view all the answers

What is the primary purpose of second-trimester ultrasound in relation to developmental diseases?

To detect neural tube defects Signup and view all the answers

What is the main identified deficiency associated with neural tube defects?

Folic acid deficiency Signup and view all the answers

What is anencephaly an example of?

Neural tube defect Signup and view all the answers

During which stage of development do malformations typically occur?

Late embryonic stage Signup and view all the answers

What is the estimated number of infants born with Fetal Alcohol Syndrome (FAS) every year in the US?

40,000 Signup and view all the answers

What is the primary concern with the use of thalidomide during pregnancy?

Neurological defects and phocomelia Signup and view all the answers

What is the effect of cigarette smoking during pregnancy on the fetus?

All of the above Signup and view all the answers

What is the effect of valproic acid on the fetus?

Increased risk of CNS and facial defects Signup and view all the answers

What was DES (Diethinylstilboestrol) initially used to treat?

Recurrent miscarriages Signup and view all the answers

What is the type of cancer that females who were exposed to diethylstilboestrol (DES) in-utero are at a higher risk of developing?

Clear cell adenocarcinoma of the vagina Signup and view all the answers

Which of the following is a characteristic of Congenital Rubella Syndrome?

Mild symptoms in the mother, but devastating effects on the embryo during the first trimester Signup and view all the answers

What is the primary mode of transmission of Herpes to the embryo or fetus?

Through the birth canal with active lesions of genital herpes Signup and view all the answers

Which of the following is a component of the TORCH syndrome?

All of the above Signup and view all the answers

What is the effect of Toxoplasmosis on the mother?

Mild problem Signup and view all the answers

What is a potential complication of a pre-diabetic mother's diabetes becoming more difficult to control during pregnancy?

Increased risk of hypertension Signup and view all the answers

What is a characteristic of toxemia of pregnancy?

Hypertension and albuminuria Signup and view all the answers

Which of the following is NOT a component of the TORCH syndrome?

Cystic fibrosis Signup and view all the answers

What is the effect of Cytomegalovirus on the developing embryo or fetus?

Can cause problems even in the third trimester Signup and view all the answers

What is a potential outcome of poor placental perfusion and poor trophoblastic invasion in toxemia of pregnancy?

Fetal growth restriction Signup and view all the answers

What is the effect of maternal infection on the developing embryo or fetus?

Can cause problems in the TORCH syndrome Signup and view all the answers

What is a characteristic of eclampsia?

Seizures in a woman with pre-eclampsia Signup and view all the answers

What is a potential complication of pre-existing hypertension during pregnancy?

Blood pressure management that may put her kidney function at risk Signup and view all the answers

What is a potential outcome of arteriolosclerosis of uterine arteries in a pre-diabetic mother?

Baby of a low birth weight Signup and view all the answers

What is the primary cause of hypoxia in a premature baby shortly after birth?

Impaired exchange of oxygen in the lungs due to immature lung development Signup and view all the answers

What is the purpose of measuring lecithin/sphingomyelin levels in amniotic fluid?

To determine the maturity of the fetus' lungs Signup and view all the answers

What is a common complication of prematurity in the cardiovascular system?

All of the above Signup and view all the answers

Why are premature babies more susceptible to bacterial sepsis?

Both a and b Signup and view all the answers

What is the approximate incidence of necrotizing enterocolitis in very low birth weight infants?

1 in 10 Signup and view all the answers

What is the primary cause of Retinopathy of Prematurity (ROP)?

Oxygen therapy Signup and view all the answers

What is a characteristic of Neonatal Respiratory Distress Syndrome (NRDS)?

Formation of a 'hyaline membrane' on the inside of the alveoli Signup and view all the answers

Why do premature babies experience more respiratory problems?

Because their lungs are not fully developed Signup and view all the answers

What is the main effect of ionizing radiation on cells?

Changes molecules in the cells directly or indirectly Signup and view all the answers

What is the effect of irradiation during the first trimester?

Miscarriage and major genetic and chromosomal abnormalities Signup and view all the answers

What is Thalidomide?

A chemical substance that causes congenital abnormalities Signup and view all the answers

What is the effect of nonionizing radiation on development?

Multifactorial and modulating effects on development Signup and view all the answers

What is the Potter Sequence an example of?

A deformation event due to lack of amniotic fluid Signup and view all the answers

What type of defect occurs when a fetus is affected by outside influences, usually during the last few weeks of pregnancy?

Deformation Signup and view all the answers

What is the consequence of a failure of a tissue to divide?

Syndactyly Signup and view all the answers

What is the type of spina bifida that involves herniation of the meninges and spinal tissue?

Myelomeningocele Signup and view all the answers

What is the term for the failure of an organ to end up in its proper position? (MACA)

Ectopia Signup and view all the answers

What is the result of a failure of an organ to mature properly?

Immaturity Signup and view all the answers

What is the consequence of a complete spina bifida?

All of the above Signup and view all the answers

What is a common way that a baby can contract gonorrhea?

By passage through an infected birth canal Signup and view all the answers

What is a possible complication of gestational diabetes for the baby?

Premature delivery with a large birth weight and potential breathing problems Signup and view all the answers

What is a characteristic of congenital syphilis?

All of the above Signup and view all the answers

How can a baby contract HIV?

All of the above Signup and view all the answers

What is a complication of gestational diabetes for the mother?

Risk of complications during pregnancy Signup and view all the answers

What is Ophthalmia Neonatorum?

An eye infection in newborns Signup and view all the answers

What is a possible long-term effect of congenital syphilis?

All of the above Signup and view all the answers

What is a major risk associated with tonic-clonic seizures during pregnancy?

Diaphragm spasm leading to hypoxia and ischemia for both mother and baby Signup and view all the answers

What is the definition of Low Birth Weight?

Less than 5 lbs or 2500g Signup and view all the answers

What is a common complication of prematurity in the baby?

Neonatal Respiratory Distress Syndrome (NRDS) Signup and view all the answers

What is a common cause of prematurity?

All the above Signup and view all the answers

What is the incidence of Low Birth Weight among black populations?

12% Signup and view all the answers

What is the primary consequence of a baby experiencing Neonatal Respiratory Distress Syndrome (NRDS)?

Formation of a "hyaline membrane" on the inside of the alveoli Signup and view all the answers

What is the test used to determine if the lungs of a fetus are mature?

Measuring the lecithin/sphingomyelin levels in the amniotic fluid Signup and view all the answers

What is a common cardiovascular problem in premature babies?

Patent ductus arteriosus (PDA) Signup and view all the answers

What is the term for the inflammatory disease that can occur in the intestines of premature babies?

Necrotizing enterocolitis Signup and view all the answers

Why do premature babies require ventilatory support?

Because their lungs are not mature enough to exchange oxygen properly Signup and view all the answers

What is a complication of therapeutic hyperoxygenation in premature babies?

Retinopathy of prematurity Signup and view all the answers

Study Notes

Developmental Diseases

Effects on different developmental stages:
- Pre-implantation (1-2 weeks) and early embryonic stage (2-3 weeks): conceptus is lost or non-affected cells replace and recover with no apparent effect (20% not surviving)
- Late embryonic stage (up to 8 weeks): formation of primitive organ systems → malformations
- Fetal stage (from 9th week after fertilization): growth and maturation → disruptions, deformations

Malformations

Failure of a space to close properly:
- Neural tube defects
  - Folic acid deficiency and B12
  - Second-trimester ultrasound and Alpha-fetoprotein screening for neural tube defects, Down syndrome, and other chromosomal abnormalities
- Anencephaly:
  - Usually blind, deaf, unaware of surroundings, and unable to feel pain
  - Born with a main brainstem, having almost all primitive reflexes of a newborn
- Spina bifida:
  - Spina bifida occulta: osseous defects only
  - Meningocele: herniation of meninges but not spinal tissue – no/minor neurological symptoms
  - Myelomeningocele: herniation of meninges and spinal tissue → neurological symptoms (sensory & motor loss from affected nerves), Arnold-Chiari malformation
  - Complete spina bifida: exposure of nervous tissue without covering membranes – as previous plus infections (meningitis)
Failure of a tissue to divide:
- Syndactyly
Failure of an embryologic structure to disappear properly:
- Thyroglossal duct cyst – from thyroid descent
- Meckel's diverticulum – from the vitelline duct or yolk stalk
Failure of a tissue or organ to form or develop properly:
- Agenesis
- Aplasia
- Hypoplasia
- Dysplasia

During the Fetal Period

Failure of an organ or body part to grow properly – hypoplasia
Failure of an organ to end up in its proper position – ectopia, dystopia
Failure of an organ to mature properly
Deformations – fetus affected by outside influences, usually occurring during the last few weeks of pregnancy when the fetus can be compressed by the uterine wall
Failure of the whole organism to grow: low birth weight baby

Teratogenic Agents Causing Congenital Abnormalities

Irradiation:
- Mostly ionizing radiation: penetrating high-energy radiation
- Direct action: changes molecules in cells
- Indirect action: causes formation of free radicals that damage cells
- Effects depending on exposure and timing of pregnancy
Chemical substances:
- Thalidomide:
  - Introduced in 1956 as a sedative, but not tested on pregnant women
  - Particularly effective antiemetic and morning sickness remedy
  - Neurological defects, limb abnormalities (phocomelia), 40% died in the first year
  - Taken off the market in November 1961, leading to the death of approximately 2,000 children and serious birth defects in >20,000 children
- Fetal Alcohol Syndrome (FAS):
  - Affects 1 in 100 live births, approximately 40,000 infants born every year
  - Leading known and preventable cause of mental retardation and birth defects
  - Effect is most likely seen with binge-drinking rather than low-level exposures, but the level at which this occurs is unclear
Infections (maternal):
- Cigarette smoking during pregnancy:
  - Higher likelihood of abnormalities of fingers and toes
  - Increases the risk of miscarriage
  - Increases the risk of complications
  - Increases the risk of preterm delivery
  - Increases the risk of having a low birth weight baby with increased risk of death
  - Increases the risk of the child developing behavioral problems
Maternal diseases:
- Renal disease:
  - Mostly growth restriction and vasculitis/arteriolosclerosis of the baby's blood vessels

Pediatric Diseases

Age distinctions and causes of death:
- Neonatal, birth – 1 month: prematurity, low birth weight, congenital abnormalities, complications at or around birth (mother & placenta), sepsis, NRDS, hypoxia/asphyxia
- Infancy, 1 month – 1 year: congenital abnormalities, SIDS, prematurity & low birth weight, infections, NRDS
- Early childhood, 1 – 5 years old: accidents, congenital abnormalities, assault, neoplasm
- Late childhood, 5 – 9 years old: accidents, neoplasm, congenital abnormalities, assault, infections

Prematurity and Intrauterine Growth Retardation

Definitions:
- Low Birth Weight: less than 5 lbs or 2500g
- Prematurity: less than 37 weeks of pregnancy
- AGA: appropriate for gestational age, may be of low weight due to prematurity
- SGA: small for gestational age, may be normal age but small weight
Incidence of low birth weight: 12% in blacks, majority are SGA
Prognosis:
- 500-600g (1.5 lbs): 2% survive
- 1% < 1500g (3 lbs) VLBW: 50% survive
- 1250g > 2 ½ lbs: 90% survive

Developmental Diseases

Effects of exposure to toxins/substances on different developmental stages:
- Pre-implantation (1-2 weeks) and early embryonic stage (2-3 weeks): conceptus is lost or non-affected cells can recover with no apparent effect (20% not surviving)
- Late embryonic stage (up to 8 weeks): formation of primitive organ systems → malformations
- Fetal stage (from 9th week after fertilization): growth and maturation → disruptions, deformations

Malformations

Failure of spaces to close properly:
- Neural tube defects
  - Folic acid deficiency is a major risk factor
  - Second-trimester ultrasound and Alpha-fetoprotein screening can detect neural tube defects, Down syndrome, and other chromosomal abnormalities
Specific malformations:
- Anencephaly: usually blind, deaf, unaware of surroundings, and unable to feel pain
- Phocomelia: limb abnormalities
- 40% mortality rate in the first year

Fetal Developmental Disorders

Fetal Alcohol Syndrome (FAS):
- Affects 1 in 100 live births (approximately 40,000 infants/year)
- Leading known and preventable cause of mental retardation and birth defects
- Characteristics: impulse control issues, disconnection of cause-effect, and mental retardation
Fetal Alcohol Effects (FAE): milder symptoms than FAS, but still present
No safe level of alcohol consumption during pregnancy

Other Teratogens

Cigarette smoking during pregnancy:
- Increases risk of abnormalities in fingers and toes
- Increases risk of miscarriage, complications, preterm delivery, and low birth weight
- Increases risk of behavioral problems in the child
Androgens (anabolic steroids/steroids): teratogenic effects
Valproic acid (antiepileptic): teratogenic effects
Retinoic acid (derivative of vitamin A):
- Malformations affecting multiple organ systems in cases of absence
- CNS, cardiac, and facial defects in cases of excess
DES (Diethinylstilboestrol): increased risk of clear cell adenocarcinoma of the vagina, cervical abnormalities, and breast cancer in females; epididymal cysts in males

Maternal Infections

TORCH syndrome:
- Toxoplasmosis: contracted through cat litter, affects fetus after 4th month
- Rubella: causes devastating effects in the embryo, especially during the first trimester
- Cytomegalovirus: can infect the embryo or fetus, causing problems even in the third trimester
- Herpes: can infect the embryo through the mother's blood or during passage through the birth canal
Components of TORCH syndrome:
- Microcephaly
- Hepatosplenomegaly, anemia, jaundice
- Petechiae, purpurae
- Chorioretinitis or conjunctivitis

Maternal Complications

Pre-diabetic mother:
- At risk for developing complications associated with pregnancy
- Baby at risk for congenital abnormalities, miscarriage, and premature delivery
Pre-existing hypertension:
- Mother at risk for developing complications associated with pregnancy
- Blood pressure management may put kidney function at risk
Toxemia of pregnancy:
- Pre-eclampsia: characterized by high blood pressure, proteinuria/albuminuria, and abnormal placental development
- Eclampsia: onset of seizures in a woman with pre-eclampsia

Congenital Abnormalities

Born with a main brainstem, having almost all the primitive reflexes of a newborn, including auditory, vestibular, touch, and pain
Spina bifida:
- Spina bifida occulta: osseous defects only
- Meningocele: herniation of meninges but not spinal tissue, with minor or no neurological symptoms
- Myelomeningocele: herniation of meninges and spinal tissue, leading to neurological symptoms and Arnold-Chiari malformation
- Complete spina bifida: exposure of nervous tissue without covering membranes, leading to infections and other symptoms
Cardiac abnormalities: ASD or VSD
Failure of tissue to divide:
- Syndactyly
- Failure of embryologic structure to disappear properly:
  - Thyroglossal duct cyst (from thyroid descent)
  - Meckel's diverticulum (from the vitelline duct or yolk stalk)

Fetal Development Abnormalities

Failure of a tissue or organ to form or develop properly:
- Agenesis
- Aplasia
- Hypoplasia
- Dysplasia
Failure of an organ or body part to grow properly:
- Hypoplasia
- Ectopia or dystopia (failure of an organ to end up in its proper position)
Deformations:
- Fetus affected by outside influences, usually occurring during the last few weeks of pregnancy when the fetus can be compressed by the uterine wall
- Example: The Potter Sequence, a cascade of events due to lack of amniotic fluid
Failure of the whole organism to grow: Low birth weight baby

Teratogenic Agents

Irradiation:
- Mostly ionizing radiation (penetrating high-energy radiation)
- Direct action: changes molecules in cells
- Indirect action: causes formation of free radicals that damage cells
- Effects depend on exposure and timing of pregnancy
Drugs and chemicals:
- Thalidomide
Infections (maternal):
- Syphilis:
  - Fetal syphilis from mother with secondary syphilis (blood disseminated)
  - Neonate has secondary syphilis (before 2 years old)
  - Late syphilis (after 2 years old): tertiary syphilis
- HIV:
  - Contracted across the placenta
  - Contracted by exposure to blood during labor and delivery
  - Contracted in breast milk
- Gonorrhea:
  - Contracted by passage through an infected birth canal
  - Causes Ophthalmia Neonatorum
Maternal diseases:
- Diabetes mellitus:
  - Gestational diabetes (develops in the last trimester of pregnancy and goes away after birth)
  - Affects 4% of pregnancies in the US
- Renal disease:
  - Mostly growth restriction and vasculitis/arteriolosclerosis of the baby's blood vessels

Pediatric Diseases

Age distinctions and causes of death:
- Neonatal (birth to 1 month): prematurity, low birth weight, congenital abnormalities, complications at or around birth, sepsis, NRDS, hypoxia/asphyxia
- Infancy (1 month to 1 year): congenital abnormalities, SIDS, prematurity, low birth weight, infections, NRDS
- Early childhood (1 to 5 years old): accidents, congenital abnormalities, assault, neoplasm
- Late childhood (5 to 9 years old): accidents, neoplasm, congenital abnormalities, assault, infections
Prematurity and intrauterine growth retardation:
- Definitions:
 - Low birth weight: less than 5 lbs or 2500g
 - Prematurity: less than 37 weeks of pregnancy
 - AGA: appropriate for gestation age
 - SGA: small for gestational age
- Incidence: 12% in blacks, mostly SGA
- Prognosis:
 - 500-600g (1.5 lbs): 2% survive
 - 1% < 1500g (3 lbs): 50% survive
 - 1250g (2 ½ lbs): 90% survive
Premature birth:
- Causes:
  - Premature rupture of membranes
  - Maternal illness, including intrauterine infections
  - Uterine abnormalities
  - Placenta abnormalities
  - Fetal disorders
  - Multiple gestation
  - Unknown
- Associated diseases in the baby after birth due to immaturity of organs:
  - Neonatal respiratory distress syndrome (NRDS)
  - Cardiovascular problems
  - Bacterial sepsis
  - Necrotizing enterocolitis

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Description

This quiz covers the effects of developmental diseases and teratogens on different stages of development, from pre-implantation to late embryonic stage. Learn how exposure to teratogens can result in malformations and other effects on the fetus.