At the end of lecture student should be able to know,
What is teratology?
Infectious agents effects.
Torch infections effects.
Chemical agents effects.
A teratogen is any infectious agent,drug,chemical or
radiation that alters fetal morphology or fetal function if
the fetus is exposed during a critical stage of
THE RESISTANT PERIOD
Week 1 of development.
Is the time when the
conceptus demonstrates the
’all or none’ phenomenon
THE MAXIMUM SUSCEPTIBILITY PERIOD
Week 3 to 8 embryonic period.
Is the time during which the embryo is most
susceptible to teratogens because all organs
morphogenesis occurs at this time.
THE LOWER SUSCEPTIBILITY PERIOD
Weeks 9 to 38 fetal period.
Time during which the fetus has a lower susceptibility to
teratogens because all organs
systems have already formed.
Teratogens expose generally results
in a functional derangement of an
May be viral or nonviral.
Viral infections may reach the fetus
via the amniotic fluid after vaginal infection transplacentally
via the bloodstream after maternal viremia,or by direct
contact during passage through an infected birth canal
Bacteria appears to be non teratogenic.
Transmitted to the fetus
Risk greatest during the first
month of pregnancy.
Fetal rubella infection results in
the classic triad of cardiac
septal defects),cataract,and low
The clinical manifestations
include intrauterine growth
involvement,osteitis,and sensorineural defects
Most common fetal infection.
Transmitted to the fetus transplacentally or by the virus
ascending from the cervix during recurrence.
Transmitted to perinates during passage through the
birth canal or through breast milk.
Clinical manifestations are
Sensorineural deafness,intrauterine growth
block,bluish purple lesions on yellow
Transmitted to the fetus transplacentally
Most commonly transmitted to the fetus by
contact during passage through an infected birth canal.
At 10 to 11days of age clinical manifestation.
Disease localized to skin,eye,mouth.
At 15 to 17days of age.
Untreated disease results in an 80%
mortality rate and
most survivors have neurologic
The only intervention to prevent infection is delivery by
cesarean section with in 4 to 6hours of ruture of
Transmitted to the fetus transplacentally.
Clinical manifestations of fetal varicella syndrome
Cicatricial(scarring) skin,digit hypoplasia,limb paresis,limb
Treatment of the neonate is by
HUMAN IMMUNODEFICIENCY VIRUS
HIV is transmitted to the fetus through
blood containing HIV or HIV infected lymphoid cells near
the time of delivery after 35days of gestation.
HIV infection does not appear to cause any congenital
malformation but results in chronic mutisystem
NON VIRAL INFECTIONS
Transmitted to the fetus
results in miscarriage,perinatal
Hydrocephalus encephalomyelitis with
Surviving infants are left with major neurological sequele(eg
mental retardation,seizure,spasticity,and visual dificits)
Infection acquired at birth
through contact with genital lesion in the birth canal.
Results in miscarriage,perinatal
blisters,nasal discharge with
rhinitis,maculopapular rash located in
erosions of the proximal medial tibia,saw tooth appearance
of metaphysis of long bones,abnormal teeth,and acute
syphilic leptomeningitis that may present as neck
stiffness,and chronic meningovascular syphilis(cranial nerve
Are caused by,
And other bacterial and viral infections that are grouped
together because they cause similar clinical and pathological
Prescribed for pregnanat women for morning sickness.
Drug cause limb reduction,ear and nasal
abnormalities,cardiac defects,lung defects,pyloris
Used in cancer chemotherapy.
Causes small stature,abnormal cranial ossification,ocular
hypertelorism,low set ears,cleft palate,myelomeningocele.
Are alkylating agents used in chemotherapy.
Cause cleft palate,eye defects,hydronephrosis,renal
agenesis,absence of toes,growth retardation.
Causes growth retardation,mental
retardation,microcephaly,craniofacial defects,nail and digit
TRIAZOLAM AND ESTAZOLAM
Are hypnotic drugs.
Causes cleft palate.
Causes stippled epiphysis,mental
atrophy in fetus.
Used in the treatment of severe acne.
Causes CNS abnormalities,external ear abnormalities,eye
abnormalities,facial dysmorphia,cleft palate.
Nonsteroid ovulatory stimulant used in women.
There are reports of birth anomalies.
Used to prevent spontaneous abortion.
Causes hypoplastic uteruspremature labour,and cervical
Causes masculinization of genitalia in female
embryo,hypospadias in males and cardiovascular
NORETHINDRONED AND LEVONORGESTROL
Are oral contraceptive.
Cause an increase of fetal abnormalities.
Particularly of VACTERL SYNDROME.
Delivered to the fetus through cigarette smokiong.
Causes intrauterine growth retardation,premature
delivery,low birth weight,and fetal hypoxia.
Causes fetal alcohol syndrome,which results in mental
Lysergic acid(LSD) has not shown to be teratogenic
Marijuana has not shown to be teratogenic.
Caffeine has not shown to be teratogenic.
Cocaine results in an increased
risks of congenital
abnormalities,still births,low birth
weight,and placental abruption.
Heroin has not shown to be teratogenic,it is the drugs
that are taken with heroin that produce congenital
anomalies.methadone used to replace heroin is not
teratogenic but is also associated with severe neonatal
ACUTE HIGH DOSE(over 250rads) of radiation results in
microcephaly,mental retardation,growth retardation,and
AFTER EXPOSURE TO GREATER THAN 25rads classic
fetal defects will be observed so that termination of
pregnancy should be offered as an option.
Radioactive iodine cocktails for organ visualization should be
avoided after 10 week of gestation because fetal thyroid
development can be impaired.
BRS(4th edition,ronald w dudek,james d fix)