Not true about thalidomide:

Has no antiangiogenesis action against tumour

Still has restricted clinical use

Not tested in pregnant animals before introduction

An infant presents with hepatosplenomegaly and thrombocytopenia. Neuroimaging with CT shows periventricular calcifications. What is the most likely diagnosis?

Congenital cytomegalovirus infection

Congenital herpes simplex virus infection

Which of the following drugs is given during pregnancy, resulting in fetal abnormalities such as cleft lip and central nervous system defects?

Retinoic acid (Vitamin A derivative)

A 7 weeks pregnant lady has 1 accidental exposure to x-ray. Which of the following should be done?

Continue the pregnancy with monitoring

Perform chromosome analysis if needed

Conduct pre-invasive diagnostic testing if indicated

Consider termination of pregnancy

24 yr old mother with 7 week POG presents to ANC OPD with accidental low-dose radiation exposure. What is the most appropriate immediate management?

Reassure and continue pregnancy

Perform detailed fetal anomaly scan

Advise medical termination of pregnancy

Advise genetic counseling and testing

Environmental Influences on Development for NEET-PG: High-Yield Anatomy Lessons

Teratogens: Principles & Timing - Bad News Bearers

Teratogen: Agent (e.g., drug, infection, radiation) causing congenital anomalies (structural/functional).
Key Principles (Wilson's):
- Susceptibility: Varies (maternal/fetal genotype, developmental stage).
- Critical Periods: Organ-specific vulnerability windows (e.g., CNS continuous; Heart: wks 3-6; Limbs: wks 4-7).
- Dose-Response: ↑dose generally → ↑effect severity; threshold may exist.
- Specific Mechanisms: Unique pathways leading to defined outcomes.
- Outcomes: Death, malformation, growth restriction, functional deficits.
Significance of Timing:
- Pre-implantation (<2 weeks post-conception): "All-or-none" effect (embryo death or normal development).
- Embryonic Period (3-8 weeks): Peak susceptibility; major structural anomalies.
- Fetal Period (>8 weeks to birth): Functional defects, minor structural anomalies, growth issues.

⭐ The first 2 weeks post-conception are often considered an 'all-or-none' period for teratogenic effects.

Infectious Teratogens: TORCH - Tiny Trouble Makers

📌 TORCH complex: Key group of congenital infections causing significant neonatal morbidity. Early maternal diagnosis & intervention are crucial.

Agent	Key Manifestations	Notes/Prevention
Toxoplasmosis	Triad: Chorioretinitis, hydrocephalus, intracranial calcifications	Avoid raw meat, cat litter.
Other: Syphilis	Hutchinson's triad (keratitis, teeth, deafness), saddle nose	Maternal screen (VDRL/RPR) & penicillin.
Other: VZV	Limb hypoplasia, skin scars, microcephaly	Pre-pregnancy vaccine; VZIG if exposed.
Other: Parvo B19	Hydrops fetalis, severe anemia	Supportive; IUT for severe anemia.
Rubella	Deafness, cataracts, cardiac (PDA), "blueberry muffin" rash	MMR vaccine (pre-pregnancy).
CMV	Hearing loss (commonest), periventricular calcifications, microcephaly	Hand hygiene. Ganciclovir if symptomatic.
HSV	Skin vesicles, encephalitis, keratoconjunctivitis	C-section (active lesions); Acyclovir.

TORCH Syndrome: Causes, Symptoms, Transmission

Chemical & Drug Teratogens - Potions & Poisons

Key teratogens, critical exposure periods, and primary effects:

Teratogen	Critical Period (Gestation)	Primary Effects
Thalidomide	Weeks 4-8	Phocomelia, limb defects
Alcohol (FAS)	Throughout	Microcephaly, facial dysmorphism. 📌 FAS Craniofacial, AIUGR, Neuro
Valproate	1st trimester (esp. <30d)	Neural Tube Defects (NTDs), cardiac/limb defects
Phenytoin	Throughout	Fetal Hydantoin Syndrome (craniofacial, hypoplastic nails)
ACE Inhibitors	2nd/3rd trimester	Renal dysgenesis, oligohydramnios
Isotretinoin	Weeks 2-5	CNS, craniofacial, cardiac defects. Highly teratogenic.
Warfarin	Weeks 6-9	Nasal hypoplasia, stippled epiphyses
Lithium	1st trimester (<8wks)	Ebstein's anomaly (cardiac)
Lead	Throughout	Neurodevelopmental deficits, miscarriage
Mercury (Organic)	Throughout	Minamata disease (severe CNS damage)

Teratogens and fetal development timeline

Physical & Maternal Factors - Womb Worries

Radiation Exposure:
- Teratogenic, esp. organogenesis (2-8 weeks).
- CNS most sensitive: microcephaly, intellectual disability (ID).
- Risk if > 5-10 rads (0.05-0.1 Gy).
Hyperthermia:
- Maternal fever > 38.9°C (1st trimester).
- Linked to Neural Tube Defects (NTDs), cardiac defects, facial clefts.
Maternal Metabolic Conditions:
- Diabetes (Pre-gestational): Poor control → caudal regression, cardiac defects, NTDs, macrosomia.
- Phenylketonuria (PKU): ↑ Phenylalanine → microcephaly, ID, Congenital Heart Disease (CHD). Strict diet vital.
- Nutritional Deficiencies:
  - Folic Acid: Deficiency → NTDs (spina bifida, anencephaly).
  - Iodine: Deficiency → cretinism.

⭐ Maternal folic acid supplementation significantly reduces the risk of neural tube defects.

High‑Yield Points - ⚡ Biggest Takeaways

TORCH infections (Toxoplasmosis, Rubella, CMV, HSV, Syphilis) are key causes of congenital anomalies.

Fetal Alcohol Syndrome shows characteristic facial dysmorphism, growth retardation, and CNS defects.

Thalidomide is linked to phocomelia (severe limb reduction defects).

Valproic acid exposure significantly ↑ risk of neural tube defects.

ACE inhibitors in 2nd/3rd trimesters cause renal dysgenesis and oligohydramnios.

Maternal diabetes links to macrosomia, cardiac defects, and caudal regression syndrome.

Radiation exposure (especially 8-15 weeks gestation) causes microcephaly and intellectual disability.

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