A 28-year-old female in the 2nd trimester of pregnancy is diagnosed with primary Toxoplasma gondii infection. Her physician fears that the fetus may be infected in utero. Which of the following are associated with T. gondii infection in neonates?

Hydrocephalus, chorioretinitis, intracranial calcifications

Hutchinson’s teeth, saddle nose, short maxilla

Deafness, seizures, petechial rash

Patent ductus arteriosus, cataracts, deafness

Temporal encephalitis, vesicular lesions

A 27-year-old woman, gravida 2, para 1, at 36 weeks' gestation comes to the physician for a prenatal visit. She feels well. Fetal movements are adequate. This is her 7th prenatal visit. She had an ultrasound scan performed 1 month ago that showed a live intrauterine pregnancy consistent with a 32-week gestation with no anomalies. She had a Pap smear performed 1 year ago, which was normal. Vital signs are within normal limits. Pelvic examination shows a uterus consistent in size with a 36-week gestation. Her blood group and type is A negative. Which of the following is the most appropriate next step in management?

Transabdominal doppler ultrasonography

A 28-year-old primigravid woman at 36 weeks' gestation comes to the emergency department because of worsening pelvic pain for 2 hours. Three days ago, she had a burning sensation with urination that resolved spontaneously. She has nausea and has vomited fluid twice on her way to the hospital. She appears ill. Her temperature is 39.7°C (103.5°F), pulse is 125/min, respirations are 33/min, and blood pressure is 130/70 mm Hg. Abdominal examination shows diffuse tenderness. No contractions are felt. Speculum examination shows pooling of nonbloody, malodorous fluid in the vaginal vault. The cervix is not effaced or dilated. Laboratory studies show a hemoglobin concentration of 14 g/dL, a leukocyte count of 16,000/mm3, and a platelet count of 250,000/mm3. Fetal heart rate is 148/min and reactive with no decelerations. Which of the following is the most appropriate next step in management?

Administer intravenous ampicillin and gentamicin and induce labor

Administer oral azithromycin and induce labor

Administer intravenous ampicillin and gentamicin and perform C-section

A mother delivers in a rural area under the guidance of a skilled care attendant. Which of the following statements is incorrect regarding the care provided by the skilled care attendant at birth?

Start breastfeeding as early as possible

Clear the eyes with a sterile swab

Dry the baby thoroughly and stimulate breathing

A 34-year-old man with a 2-year history of rheumatoid arthritis is being evaluated on a follow-up visit. He is currently on methotrexate and celecoxib for pain management and has shown a good response until now. However, on this visit, he mentions that the morning stiffness has been getting progressively worse. On physical examination, both his wrists are erythematous and swollen, nodules on his elbows are also noted. Rheumatoid factor is 30 (normal reference values: < 15 IU/mL), ESR is 50 mm/h, anti-citrullinated protein antibodies is 55 (normal reference values: < 20). What is the next best step in the management of this patient?

Methotrexate and Corticosteroids

Maternal factors and neonatal infection risk for USMLE Step 3: High-Yield Pediatrics Lessons

Antenatal Factors - Womb Invaders

Infections transmitted transplacentally at any stage of gestation.
📌 TORCH: Toxoplasmosis, Other (Syphilis, VZV, Parvo B19), Rubella, Cytomegalovirus, Herpes simplex.

Agent	Key Maternal Feature	Key Neonatal Sign
Toxoplasma	Asymptomatic; mono-like illness	Triad: Chorioretinitis, hydrocephalus, diffuse intracranial calcifications
Rubella	Fever, postauricular lymphadenopathy, maculopapular rash	Triad: Cataracts, PDA, sensorineural deafness; 'blueberry muffin' rash
CMV	Asymptomatic; mono-like illness	Periventricular calcifications, microcephaly, sensorineural hearing loss
HSV	Genital vesicular lesions	Skin-Eye-Mouth (SEM) disease, encephalitis, disseminated sepsis
Syphilis	Chancre, rash on palms/soles	Snuffles, 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.

Continue reading on Oncourse

CONTINUE READING — FREE

or get the app

App Store|Google Play