Teratogenicity and Birth Defects

Study Notes

Most common cause of birth defects in children is multifactorial.
First month of pregnancy (preimplantation) exposure causes embryonic lethality.
Pre-organogenesis (end of 1-2 months) causes morphological defects.
Fetal second and third trimester cause functional disorders, growth retardation, and carcinogenesis.
Folic acid deficiency can cause neural tube defects.
Anticonvulsants, hyperthermia, trimethoprim, and valproic acid can cause developmental problems.
Corticosteroids can result in cleft palate and adrenal atrophy.
Diabetes mellitus may cause polycythemia, cardiomyopathy, and hypoglycemia.
Tetracycline can lead to enamel dysplasia.
Warfarin can cause nasal hypoplasia.
Systemic lupus can cause congenital heart block.
Rubella, phenylketonuria, and lithium can cause mental retardation and patent ductus arteriosus.
Syphilis and retinoids can cause hydrocephalus.
Rubella can cause microcephaly (but not macrocephaly).
Streptomycin can cause deafness.
Anti-epileptics like sodium valproate can cause neural tube defects.
Thalidomide causes phocomelia.
Diabetes mellitus can cause respiratory distress syndrome.
Anti-parasitics like metronidazole are generally safe during the second and third trimesters.
Varicella zoster (chicken pox) can cause developmental issues.

Very low birth weight is less than 1500 grams.
Low birth weight is less than 2.5 kg.
Apgar score of 7 or higher in the 5th minute indicates healthy condition.
Case studies illustrating varying conditions (heart rate, response to stimuli, etc.) and corresponding Apgar scores.
Large for gestational age: baby's weight above 90th percentile.
Post-term newborn: gestational age more than 42 weeks.
Low birth weight: weight below 2500 grams.
Average birth weight: at the 50th percentile.
Small for gestational age: weight below 10th percentile.
Preterm newborns: born before 37 weeks.
Neonatal examination includes reflexes like tonic neck reflex, important risk factors (e.g., intraventricular hemorrhage), Erb's palsy, cephalhematoma, and primitive reflexes.

Reflex development in the first month is crucial.
Tonic neck reflex.
Critical risk factors, like intraventricular hemorrhage, can cause severe complications.
Erb's Palsy, associated with phrenic nerve damage, can lead to weakness in the affected arm.
Cephalhematoma, caused by bleeding between the skull bones, typically resolves within a few weeks.
Asymmetric Moro reflex is indicative of one-sided damage.
Positive Moro reflex, in full-term newborns, suggests normal development.
Positive Moro and primitive reflexes are seen in infants with appropriate development.
Head overlapping of the skull bones is normal for facilitating delivery.
Respiratory distress is a common cause of mortality in premature infants.
Abnormal findings in healthy full-term babies, like intra-cranial hemorrhage, are critical.

Treatment for hypothermia includes kangaroo care.
Normal newborn temperature ranges from 36.5 to 37.5 degrees Celsius.
Infants lose heat rapidly due to a larger surface area to body mass ratio.
Axillary and rectal temperatures are used for measurement.
Moderate hypothermia ranges from 32 to 36 degrees Celsius.
Management of hypothermia involves radiant warmers, servo-control, and maintaining proper body temperature.
Hypoglycemia is a common issue in hypothermic infants.
Infection is a frequent cause of hyperthermia in infants.