Birth Defects and Prenatal Diagnosis, Embryology NOT FINISHED

The study of birth defects:

Teratology/dysmorphology

Birth defect is also known as:

Congenital malformation

Congenital anomaly

Congenital malformations can be:

Structural, behavioral, functional, and metabolic disorder at birth

Major structural anomalies occur in how many live-born infants?

3%

Birth defects are a leading cause of infant mortality, accounting for:

25% of infant deaths

Birth defects can be caused by:

1. Environmental (15%)

2. Genetic factors (30%)

3. Multifactorial (interaction of environmental and genetic + of unknown origin

Many malformations occur during the formation of structures like:

organogenesis (3rd-8th week)

Axis formation begins late in the 1st week at the blastocyst stage, which can cause:

a great variety of birth defects, can be caused by disruptions in cell signaling during specification of cranial-caudal and left-right axes

This results in morphologic alternations of already formed structures and are caused by destructive processes

Disruption

What can cause disruptions?

Vascular accidents leading to transverse limb defects and defects produced by amniotic bands

this can result for mechanical forces that mold a part of a fetus over prolonged period of time

Deformation

A birth defect that affects the limbs, loss of long bones:

Phocomelia

Cytomegalovirus can cause:

serious/fatal at birth, delayed hearing loss, visual impairment, intellectual disability

Herpes simplex virus can cause:

Severe illness or death

Varicella virus can cause:

scarring of skin, limb hypoplasia, defects of eyes and CNS

Zika virus can cause:

Severe microcephaly, thinning of cerebral cortex, microphthalmia, coloboma, joint contractures, neurologic sequelae

Toxoplasmosis (protozoan parasite) can cause:

brain damage, vision/hearing loss

what infectious agents can cause birth defects?

1. Rubella

2. CMV

3. Herpes simplex virus

4. Varicella virus

5. Zika virus

6. Toxoplasmosis

Why is radiation considered a potent teratogen?

Kills rapidly proliferating cells

Drugs and chemical agents that can cause birth defects:

1. thalidomide

2. Accutane

3. Seizure disorder medication

4. Antipsychotics/anti-anxiety agents

5. Antidepressants

6. Zofran

7. Opiod

Any treatment for infertility (chemical induction of ovulation or IFV):

is associated with risk for stillbirths, low birth weight and prematurity

Approaches for asessing growth and development of fetus in utero:

Ultrasound

Maternal serum screening

Amniocentesis

Chorionic villus sampling

Cordcentesis