teratogens and other influences on development. scenario

Teratogens and Other Teratogens and Other Influences on DevelopmentInfluences on Development

ScenarioScenario

You return after class one day to find a message in your You return after class one day to find a message in your voice mail from your cousin’s husband, who is obviously voice mail from your cousin’s husband, who is obviously upset. He has called to tell you that your cousin, Karen has upset. He has called to tell you that your cousin, Karen has just given birth more than 2 months early to a little boy who just given birth more than 2 months early to a little boy who weighs slightly less than 4 pounds. weighs slightly less than 4 pounds.

Karen’s pregnancy had been planned and completely Karen’s pregnancy had been planned and completely normal and she had followed her doctor’s advice to the normal and she had followed her doctor’s advice to the letter, so this outcome comes as a complete shock. The letter, so this outcome comes as a complete shock. The baby has been moved to the neonatal intensive care unit. baby has been moved to the neonatal intensive care unit. You’re very close to Karen and know that she will want to You’re very close to Karen and know that she will want to see you as soon as possible. see you as soon as possible.

When you visit her in the hospital, Karen tells you that the When you visit her in the hospital, Karen tells you that the baby is in stable condition but that she’s deeply worried baby is in stable condition but that she’s deeply worried about what the future holds for him and for the family. She about what the future holds for him and for the family. She shares her fear that he will never have a normal life. shares her fear that he will never have a normal life.

From what you’ve learned about pre-natal development in From what you’ve learned about pre-natal development in your child development class, what can you tell Karen about your child development class, what can you tell Karen about her new son’s chances for normal development? If she her new son’s chances for normal development? If she asks for your advice, what would you tell her?asks for your advice, what would you tell her?

Teratogens and Other Teratogens and Other Influences on DevelopmentInfluences on Development

Pregnancy and AlcoholPregnancy and Alcohol

TerminologyTerminology

Teratogen: any environmental agent that Teratogen: any environmental agent that causes damage to the fetus during causes damage to the fetus during prenatal period.prenatal period.– viruses, drugs, chemicals, and radiationviruses, drugs, chemicals, and radiation– others categories?others categories?


95% of all newborns are born without problematic 95% of all newborns are born without problematic developments. developments. Of the remaining 5%, Of the remaining 5%, – 3% have mild, temporary or reversible defects. 3% have mild, temporary or reversible defects. – only 2% having continuing effects.only 2% having continuing effects.

Effect- What happens- Effect- What happens- the developmental outcome or the developmental outcome or consequence of exposure to a teratogenconsequence of exposure to a teratogen– variation in the development of the embryo, fetus, or child.variation in the development of the embryo, fetus, or child.

Mechanism- How it happens- Mechanism- How it happens- the physiological or the physiological or biological processes that explains the cause or how biological processes that explains the cause or how specific events occurspecific events occur


Sensitive Period-Sensitive Period- That broad period of time That broad period of time when, if an insult occurs, there are likely to be when, if an insult occurs, there are likely to be consequences.consequences. – insults may occur over a broad period of time or in a insults may occur over a broad period of time or in a

number of ways number of ways e.g., the neurobehavioral effects due to exposure of alcohol e.g., the neurobehavioral effects due to exposure of alcohol during last trimesterduring last trimester

Critical Period-Critical Period- A A specificspecific period of time during period of time during which, if an insult occurs, a particular which, if an insult occurs, a particular consequence consequence willwill happen happen– Malformation of ears due to thalidomide exposure on Malformation of ears due to thalidomide exposure on

days 34-38 of PND.days 34-38 of PND.

Characteristics and Effects of TeratogensCharacteristics and Effects of Teratogens

Time of exposureTime of exposure– Worst effects= period when a body part or organ Worst effects= period when a body part or organ

system is developing. system is developing. – When is this? When is this?

Susceptibility to harm variesSusceptibility to harm varies– Not all embryos or fetuses are affected in the same Not all embryos or fetuses are affected in the same

way by the same exposure. way by the same exposure. Characteristics of the fetus influence the effects Characteristics of the fetus influence the effects Studies with identical twins frequently show that one twin Studies with identical twins frequently show that one twin has impairment from a teratogen while the other doesn’t.has impairment from a teratogen while the other doesn’t.Research on FAS shows that ½ ounce/day can cause Research on FAS shows that ½ ounce/day can cause neurobehavioral problems in some children, while some neurobehavioral problems in some children, while some children born to alcoholic mothers don’t get FASchildren born to alcoholic mothers don’t get FAS


Different teratogens can cause the same Different teratogens can cause the same defect (equifinality)defect (equifinality)

– For example: ADHD may be caused byFor example: ADHD may be caused bychronic stress experienced by the mother during chronic stress experienced by the mother during pregnancypregnancy

exposure to drugs during pregnancyexposure to drugs during pregnancy

exposure to alcohol during pregnancyexposure to alcohol during pregnancy


Single teratogen may cause more than 1 Single teratogen may cause more than 1 defect (multifinality)defect (multifinality)

– Rubella may cause blindness, deafness, Rubella may cause blindness, deafness, and mental impairmentsand mental impairments

– Exposure to alcohol may cause physical Exposure to alcohol may cause physical malformations, growth retardation, and malformations, growth retardation, and mental retardation.mental retardation.


Dose Response (more is worse than less)Dose Response (more is worse than less)– FAS- Fetal Alcohol SyndromeFAS- Fetal Alcohol Syndrome

Associated with heavy drinking throughout pregnancyAssociated with heavy drinking throughout pregnancy

Results- much more severe: physical malformations, Results- much more severe: physical malformations, major mental retardationmajor mental retardation

– FAE- Fetal Alcohol EffectsFAE- Fetal Alcohol EffectsAssociated with binge drinking, or occasional drinking- Not Associated with binge drinking, or occasional drinking- Not as heavy, not as oftenas heavy, not as often

Results: Behavioral/emotional effectsResults: Behavioral/emotional effects


Father’s exposure to teratogens also Father’s exposure to teratogens also increases riskincreases risk

WHY??????WHY??????– Because sperm take 72 hours to mature and during Because sperm take 72 hours to mature and during

this period the sperm are susceptible to this period the sperm are susceptible to malformations due to environmental exposuresmalformations due to environmental exposures

– Tetracycline (discolors the enamel of the infant’s Tetracycline (discolors the enamel of the infant’s teeth). teeth).

Typically associated with mom, but it is also true if dad Typically associated with mom, but it is also true if dad takes it.takes it.


Long-term outcomes can be mediated by Long-term outcomes can be mediated by postnatal experiencepostnatal experience

– ““Effect” may be a susceptibilityEffect” may be a susceptibility– Long term high quality care and enriched Long term high quality care and enriched

environment helps OVERCOME or minimize environment helps OVERCOME or minimize bad startbad start

– HIV Babies with parents who were drug and HIV Babies with parents who were drug and alcohol users did better than non. WHY??alcohol users did better than non. WHY??

The SpecificsThe Specifics

DiseasesDiseases

Rubella-German Measles- “Timing” is keyRubella-German Measles- “Timing” is key– 1st Trimester is likely to cause more serious impairments1st Trimester is likely to cause more serious impairments

Heart defects- 1st 8 weeks (germinal/embryonic)Heart defects- 1st 8 weeks (germinal/embryonic)Cataracts-Cataracts- “ ““ “Deafness- last half of 1st trimesterDeafness- last half of 1st trimester

– Risk of having impairments (as well as the severity of them) Risk of having impairments (as well as the severity of them) decreases with time-decreases with time-

60-85% have impairments if exposed in the first 8 weeks60-85% have impairments if exposed in the first 8 weeks50% if exposed in the 3rd month50% if exposed in the 3rd month16% if exposed in the 2nd trimester16% if exposed in the 2nd trimester

– 2nd Trimester2nd TrimesterMinor mental deficienciesMinor mental deficienciesMotor impairmentsMotor impairmentshearing impairmenthearing impairment

DiseasesDiseasesToxoplasmosis –Beware of the Toxoplasmosis –Beware of the household pet!!!household pet!!!

– 1st trimester1st trimesterSevere CNS damageSevere CNS damage

Damage to the eyes and visual systemDamage to the eyes and visual system

– Later trimestersLater trimestersincreased miscarriageincreased miscarriage

jaundice- problem with liver functioning- used to jaundice- problem with liver functioning- used to be major cause of MRbe major cause of MR

pneumonia- inflammation of the lungspneumonia- inflammation of the lungs

myocarditismyocarditis

STDsSTDs

Syphilis (treatment matters!!!)Syphilis (treatment matters!!!)– 1st and 2nd trimester (<18 weeks) No effect if 1st and 2nd trimester (<18 weeks) No effect if

treatment clears infection.treatment clears infection.– Why?Why?

The organism cannot cross the placenta < 18 The organism cannot cross the placenta < 18 weeksweeks

– 2nd and 3rd trimester (>18 weeks)- impairs organs 2nd and 3rd trimester (>18 weeks)- impairs organs after they developafter they develop

Lesions of the eyes, optic nerve atrophyLesions of the eyes, optic nerve atrophyProblems with the liver functioningProblems with the liver functioningBone malformationsBone malformationsHeart malformationsHeart malformations

– If present at birth, CNS impairment and If present at birth, CNS impairment and gastrointestinal tract problemsgastrointestinal tract problems

STDs (read on own)STDs (read on own)

Chlamydia (timing doesn’t seem to Chlamydia (timing doesn’t seem to matter)matter)

– Infected mothers are more likely to miscarry Infected mothers are more likely to miscarry or have stillborn infantsor have stillborn infants

– If the disease is transmitted to the infant at If the disease is transmitted to the infant at birth, results in pneumonia and/or birth, results in pneumonia and/or conjunctivitis- Both “easily” treatedconjunctivitis- Both “easily” treated

STDs(read on own)STDs(read on own)

Genital Herpes (23% of all adults have HSV 2, only Genital Herpes (23% of all adults have HSV 2, only 1/10 know they have it)1/10 know they have it)

– 700,000 new cases each year700,000 new cases each year– >350,000 new cases are women each year>350,000 new cases are women each year– 80,500 women who are pregnant each year have new cases 80,500 women who are pregnant each year have new cases

of HSVof HSV– 1/15,000 births- neonatal HSV infection1/15,000 births- neonatal HSV infection– infected infants (EFFECTS): infected infants (EFFECTS):

1/3 of infants die1/3 of infants die1/3 have permanent & moderate to severe brain damage1/3 have permanent & moderate to severe brain damage1/3 have mild impairments including liver probs, cns impairment, 1/3 have mild impairments including liver probs, cns impairment, respiratory functionrespiratory function

– C-Section is recommended if infection is known pre-birthC-Section is recommended if infection is known pre-birth

HIV (read in your text, p. 99)HIV (read in your text, p. 99)

HIVHIV– Can be latent for years (10-15 if you are in Can be latent for years (10-15 if you are in

otherwise good shape)otherwise good shape)– Transmitted from mother to fetus either prenatally, Transmitted from mother to fetus either prenatally,

at birth, or through the mothers milk (postnatally)at birth, or through the mothers milk (postnatally)– 30% of pregnant women with HIV have babies who 30% of pregnant women with HIV have babies who

become infected.become infected.– 8% transmission when mother uses AZT treatment 8% transmission when mother uses AZT treatment

during pregnancy and for the infant after birthduring pregnancy and for the infant after birth– In twin studies where a vaginal delivery occurs, the In twin studies where a vaginal delivery occurs, the

first infant is 5X more likely to become infected- first infant is 5X more likely to become infected- Why?Why?

– Cesarean section is recommendedCesarean section is recommended

HormonesHormones

Oral ContraceptivesOral Contraceptives– Cardiovascular problemsCardiovascular problems

– 3-6 months off BEFORE pregnancy- Longer 3-6 months off BEFORE pregnancy- Longer if you’ve been on the pill for a long timeif you’ve been on the pill for a long time

Depo ProveraDepo Provera– 6-18mo6-18mo– Bone lossBone loss

MedicationsMedications

DES (dielthystilbestrol)- Used to prevent DES (dielthystilbestrol)- Used to prevent miscarriages and premature deliveriesmiscarriages and premature deliveriesIf prenatal exposure:If prenatal exposure:

– Increased risk of cervical cancer in Increased risk of cervical cancer in daughters- can be born with no uterus or daughters- can be born with no uterus or fallopian tubesfallopian tubes

– Increased risk of fetal feminization (one Increased risk of fetal feminization (one testicle, recessed testes) or hypospadias testicle, recessed testes) or hypospadias

– Higher rate of reproductive problems for Higher rate of reproductive problems for both sons and daughtersboth sons and daughters

MedicationsMedications

– Thalidomide- drug used to stop morning Thalidomide- drug used to stop morning sicknesssickness

Not pre-tested on pregnant humansNot pre-tested on pregnant humans

34-38 days malformations of the ears34-38 days malformations of the ears \\

38-46 days- malformations of the arms38-46 days- malformations of the arms

40-46 days- malformations of the legs40-46 days- malformations of the legs //

Direction of development?Direction of development?

Good ex of cephal

Environmental TeratogensEnvironmental Teratogens

What are they?What are they?

Methyl mercury- Pollutant found in fish Methyl mercury- Pollutant found in fish (very high quantities in some areas of (very high quantities in some areas of Japan, Puget Sound???)Japan, Puget Sound???)

– Increased birth weight Increased birth weight C-Sections C-Sections– Neurobehavioral effects (ADD, ADHD, Neurobehavioral effects (ADD, ADHD,

Learning disorder)Learning disorder)

Lead Poisoning- found in old paint and Lead Poisoning- found in old paint and water pipeswater pipes

– Anemia- treatableAnemia- treatable– Encephalopathy- abnormal development of Encephalopathy- abnormal development of

the brain & MRthe brain & MR– Young children and infants who are lead Young children and infants who are lead

poisoned can get MR-Method of ingestion?poisoned can get MR-Method of ingestion?

Environmental TeratogensEnvironmental Teratogens

Social DrugsSocial Drugs

Alcohol- 43% of alcoholic mothers have FAS kids Alcohol- 43% of alcoholic mothers have FAS kids (other 57% have FAE)(other 57% have FAE)

– Full blown FAS:Full blown FAS:early exposure (specifically days 19-23)- results in facial early exposure (specifically days 19-23)- results in facial dysmorphology- Diagnostic criteriadysmorphology- Diagnostic criteria– wide set eyes (small eyes)wide set eyes (small eyes)– thin upper lipthin upper lip– flat filtrumflat filtrumrepeated exposure, throughout pregnancy (early/late)repeated exposure, throughout pregnancy (early/late)– microencephalymicroencephaly– mental retardation (mild to severe)mental retardation (mild to severe)– growth retardation (<10% on growth charts)growth retardation (<10% on growth charts)Late exposure (last trimester)Late exposure (last trimester)– Decreased birth weightDecreased birth weight– HyperactivityHyperactivity– Emotional lability (inability to control emotions/lots of emotional Emotional lability (inability to control emotions/lots of emotional

outbursts)outbursts)

FASFAS

Social Drugs- AlcoholSocial Drugs- Alcohol

MECHANISM- How does it work?MECHANISM- How does it work?– Mom’s ability to metabolize alcohol is reduced Mom’s ability to metabolize alcohol is reduced

during pregnancy- decreases as pregnancy during pregnancy- decreases as pregnancy advancesadvances

– breakdown of alcohol uses extra oxygen- reduces breakdown of alcohol uses extra oxygen- reduces the amount that is available to the developing the amount that is available to the developing organismorganism

– Alcohol can cross the placenta which impairs Alcohol can cross the placenta which impairs embryonic and fetal developmentembryonic and fetal development

– Fetus’s ability to metabolize alcohol is 50% of Fetus’s ability to metabolize alcohol is 50% of mom’s (so alcohol remains longer at the end of mom’s (so alcohol remains longer at the end of pregnancy)pregnancy)

Video- FAEVideo- FAE


Smoking (nicotine)Smoking (nicotine)– EffectsEffects

Decreased birthweightDecreased birthweightDecreased heart rateDecreased heart rateincreased spontaneous abortionsincreased spontaneous abortionsincreased perinatal mortalityincreased perinatal mortalityincreased hyperactivity, ADHD, ADDincreased hyperactivity, ADHD, ADDPatch??Patch??

– MechanismMechanismreduced oxygen available to the developing fetus-different reduced oxygen available to the developing fetus-different waysways

Increased heart rate and blood pressureIncreased heart rate and blood pressure


Caffeine- Caffeine- – Not as much known. Studies have Not as much known. Studies have

conflicting results. conflicting results. – Increases heart rateIncreases heart rate– Increases blood pressureIncreases blood pressure– Constricts blood vesselsConstricts blood vessels– Dehydrates, so probably reduces the Dehydrates, so probably reduces the

oxygen supplyoxygen supply

Illegal DrugsIllegal Drugs

Marijuana- small numbers of studies- Marijuana- small numbers of studies- WHY?????WHY?????

– Moms who smoke during pregnancyMoms who smoke during pregnancyAttention may be impairedAttention may be impairedbabies are smallerbabies are smaller

– Moms who smoke during pregnancy:Moms who smoke during pregnancy:have better parent-infant relationship at 1 month of agehave better parent-infant relationship at 1 month of agehave calmer babieshave calmer babiesHave better social interactions with the infantHave better social interactions with the infant

– Problem with the internal validity. Why??Problem with the internal validity. Why??Self-selected groupSelf-selected group may have more “relaxed” view of the may have more “relaxed” view of the world, so therefore have more “lax” relationship with the world, so therefore have more “lax” relationship with the childchild

Illegal DrugsIllegal Drugs

CocaineCocaine– Effects:Effects:

Decreased gestational ageDecreased gestational ageIncreased low birth weightIncreased low birth weightPlacental abruptionPlacental abruptionIncreased rates of birth defects- Malformations of the Increased rates of birth defects- Malformations of the heart, CNS, gastrointestinal tractheart, CNS, gastrointestinal tractIncreased hyperactivity, ADD at school age.Increased hyperactivity, ADD at school age.

– Mechanism?Mechanism?reduced oxygen supplyreduced oxygen supply

– Study with 300 exposed & 300 non-exposed, Study with 300 exposed & 300 non-exposed, controlling for SES found that Low SES had a controlling for SES found that Low SES had a greater effect on the infant development than greater effect on the infant development than cocaine.cocaine.

Low B-W and Pre-term- PrematureLow B-W and Pre-term- Premature

Low birth weight and pre-term birthLow birth weight and pre-term birth– Low birth weight= < 2500g or 5.5 lbsLow birth weight= < 2500g or 5.5 lbs– Pre-term birth = < 35 weeks (post conception)- Not Pre-term birth = < 35 weeks (post conception)- Not

necessarily badnecessarily bad– Small for dateSmall for date– Influences on the size of the infantInfluences on the size of the infant

Mother’s ht, wtMother’s ht, wtMother’s ageMother’s ageMother’s weight at birthMother’s weight at birthEnvironmental variables (teratogens?)Environmental variables (teratogens?)NutritionNutritionBirth orderBirth order

Gestational weight, Birth weight, Gestational weight, Birth weight, and Survivaland Survival

Low Birth weight & survivalLow Birth weight & survivalWeight at birthWeight at birth % survival% survival1 – 1 ½ lbs1 – 1 ½ lbs 33%33%1 ¾ - 2 lbs1 ¾ - 2 lbs 67%67%2 ¼ - 3 lbs2 ¼ - 3 lbs 84%84%3 – 3 ½ lbs3 – 3 ½ lbs 91%91%>5 ½ lbs>5 ½ lbs 98%98%

Pre-term birth & survival to 1 yearPre-term birth & survival to 1 yearGestational age @ birthGestational age @ birth

<24 weeks<24 weeks 35%35%24-25 weeks24-25 weeks 63%63%26-29 weeks26-29 weeks 86%86%30-32 weeks30-32 weeks 93%93%33-36 weeks33-36 weeks 98%98%37-40 weeks37-40 weeks 99.3%99.3%41+ weeks41+ weeks 99.4 %99.4 %

Birth weightBirth weight

<14 or >40, increased risk<14 or >40, increased risk

Babies BW

14 40 Maternal Age (in years)

teratogens and other influences on development. scenario

Documents

pregnancy slide

development slide

alcohol slide

pregnancy exposure

development pregnancy

alcohol pregnancy

exposure of alcohol

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