Maternal factors and neonatal infection risk

Maternal factors and neonatal infection risk

Maternal factors and neonatal infection risk

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Antenatal Factors - Womb Invaders

  • Infections transmitted transplacentally at any stage of gestation.
  • 📌 TORCH: Toxoplasmosis, Other (Syphilis, VZV, Parvo B19), Rubella, Cytomegalovirus, Herpes simplex.
AgentKey Maternal FeatureKey Neonatal Sign
ToxoplasmaAsymptomatic; mono-like illnessTriad: Chorioretinitis, hydrocephalus, diffuse intracranial calcifications
RubellaFever, postauricular lymphadenopathy, maculopapular rashTriad: Cataracts, PDA, sensorineural deafness; 'blueberry muffin' rash
CMVAsymptomatic; mono-like illnessPeriventricular calcifications, microcephaly, sensorineural hearing loss
HSVGenital vesicular lesionsSkin-Eye-Mouth (SEM) disease, encephalitis, disseminated sepsis
SyphilisChancre, rash on palms/solesSnuffles, saber shins, Hutchinson teeth, rhagades

Exam Favourite: Cytomegalovirus (CMV) is the most common congenital infection worldwide.

Intrapartum Factors - Birth Canal Gauntlet

  • Primary Threat: Ascending infection from maternal genital tract post-rupture of membranes.
  • Key Pathogens: Group B Streptococcus (GBS), E. coli, Listeria monocytogenes.
  • Major Risk Factors:
    • Prolonged Rupture of Membranes (PROM): > 18 hours
    • Maternal intrapartum fever (Chorioamnionitis): Temp ≥ 38°C
    • Preterm delivery: < 37 weeks
    • Maternal GBS colonization, especially with heavy rectovaginal load.

⭐ Adequate intrapartum antibiotic prophylaxis (IAP) for GBS is defined as receiving IV Penicillin G or Ampicillin for at least 4 hours before delivery.

Postnatal & Systemic Factors - Beyond Delivery

  • Postnatal Exposure & Environment
    • Nosocomial Infections (NICU): Risk ↑ with invasive lines, ventilation, and prolonged stay. Common pathogens: Staphylococcus aureus, Klebsiella, Pseudomonas, Candida.
    • Community/Home: Poor hand hygiene, overcrowding, contaminated water/formula.
  • Maternal Systemic Illness
    • Diabetes Mellitus: Poor glycemic control impairs neonatal neutrophil function, increasing susceptibility.
    • Immunodeficiency: Conditions like HIV or use of immunosuppressive drugs.
  • Feeding Method
    • Formula Feeding: Lacks protective antibodies; risk of contamination.
    • Breastfeeding: Confers passive immunity.

⭐ Breast milk is rich in secretory IgA, lactoferrin, and lysozymes, which provide crucial protection against gut and respiratory pathogens.

High-Yield Points - ⚡ Biggest Takeaways

  • Group B Streptococcus (GBS) is the leading cause of early-onset neonatal sepsis.
  • Intrapartum antibiotic prophylaxis (IAP), typically with IV Penicillin G, is critical for GBS-positive mothers.
  • Prolonged Rupture of Membranes (PROM >18 hours) significantly elevates sepsis risk.
  • Maternal intrapartum fever is a cardinal sign of chorioamnionitis.
  • Preterm birth (<37 weeks) is the single most significant risk factor for neonatal infection.
  • Untreated maternal UTIs or other infections are also key risk factors.

Practice Questions: Maternal factors and neonatal infection risk

Test your understanding with these related questions

A 6-year-old boy and his parents present to the emergency department with high-grade fever, headache, and projectile vomiting. The boy was born at 39 weeks gestation via spontaneous vaginal delivery. He is up to date on all vaccines and is meeting all developmental milestones. Past medical history is noncontributory. He has had no sick contacts at school or at home. The family has not traveled out of the area recently. He likes school and playing videogames with his younger brother. Today, his blood pressure is 115/76 mm Hg, heart rate is 110/min, respiratory rate is 22/min, and temperature is 38.4°C (101.2°F). On physical exam, the child is disoriented. Kernig’s sign is positive. A head CT was performed followed by a lumbar puncture. Several aliquots of CSF were distributed throughout the lab. Cytology showed high counts of polymorphs, biochemistry showed low glucose and elevated protein levels, and a gram smear shows gram-positive lanceolate-shaped cocci alone and in pairs. A smear is prepared on blood agar in an aerobic environment and grows mucoid colonies with clearly defined edges and alpha hemolysis. On later evaluation they develop a ‘draughtsman’ appearance. Which one of the following is the most likely pathogen?

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Flashcards: Maternal factors and neonatal infection risk

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What is the first type of immunoglobulin produced in a neonate? _____

TAP TO REVEAL ANSWER

What is the first type of immunoglobulin produced in a neonate? _____

IgM

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