Perinatal Infection Exposures: Newborn Management
The first-hours playbook for newborns exposed to maternal infection
Hepatitis B and C
Universal birth dose. Every medically stable newborn weighing ≥2,000 g receives hepatitis B vaccine within 24 hours of birth; infants under 2,000 g born to HBsAg-negative mothers get their first dose at 1 month or at discharge.
- HBsAg-positive mother: hepatitis B vaccine plus hepatitis B immune globulin (HBIG) at separate sites within 12 hours, whatever the birth weight.
- Unknown status: vaccine within 12 hours while the mother is tested; if she is positive, HBIG within 7 days. Infants under 2,000 g get HBIG within 12 hours if maternal status cannot be confirmed.
- Preterm infants under 2,000 g: a birth dose does not count toward the series, so three more doses follow.
Follow-up. Exposed infants have post-vaccination testing for HBsAg and anti-HBs at 9–12 months, not earlier, because passive anti-HBs from HBIG can persist and late infection may be missed. HBsAg positivity means infection and referral; anti-HBs <10 mIU/mL with negative HBsAg means nonresponse and revaccination. Breastfeeding is allowed. Mothers with high HBV DNA levels receive tenofovir in the third trimester to lower transmission further.
Hepatitis C. Breastfeeding is also allowed unless the nipples are cracked or bleeding. Because maternal antibody persists, exposed infants are tested with HCV RNA at 2–6 months rather than with antibody tests.
HIV-exposed infants
Prophylaxis by risk. Maternal antiretroviral therapy with a suppressed viral load reduces transmission to below 1%. Infant antiretrovirals start as soon as possible, ideally within 6 hours and no later than 12. A low-risk infant (mother on ART, adherent, suppressed near delivery) receives zidovudine for 2–6 weeks. A high-risk infant (no antepartum ART, detectable viral load near delivery, or acute maternal HIV) receives presumptive three-drug therapy such as zidovudine, lamivudine, and nevirapine or raltegravir.
- BirthStart prophylaxis; nucleic acid test (NAT) now if high risk.
- 14–21 daysHIV RNA or DNA PCR.
- 1–2 monthsNAT, ideally 2–6 weeks after prophylaxis ends; negative NATs at ≥14 days and ≥4 weeks presumptively exclude infection.
- 4–6 monthsNAT; negatives at ≥1 month and ≥4 months definitively exclude infection.
Never use antibody tests to diagnose infant HIV: maternal IgG can keep them positive for 18–24 months.
Other care. Trimethoprim-sulfamethoxazole prophylaxis against Pneumocystis starts at 4–6 weeks unless infection has already been presumptively excluded. In the US, formula feeding removes postnatal transmission risk, and breastfeeding by a mother with sustained viral suppression on ART is supported through shared decision-making.
Neonatal herpes simplex
Transmission. Most infections are acquired during delivery; risk is highest when the mother has a primary infection near term, and most mothers of infected infants have no known history of herpes. Cesarean delivery is offered when genital lesions or prodromal symptoms are present at labor.
Three forms. Skin-eye-mouth disease appears in the first 2 weeks with vesicles or keratoconjunctivitis. Disseminated disease, around the second week, resembles bacterial sepsis with hepatitis, DIC, and pneumonitis. CNS disease presents at 2–3 weeks with seizures, lethargy, poor feeding, and fever. Vesicles are absent in a large share of CNS and disseminated cases, so a febrile or seizing neonate with high transaminases or CSF pleocytosis needs HSV testing.
Workup and treatment. Obtain surface swabs (conjunctiva, mouth, nasopharynx, rectum) plus blood and CSF HSV PCR and an ALT. IV acyclovir 60 mg/kg/day is given for 14 days for skin-eye-mouth disease and 21 days for CNS or disseminated disease, with a repeat CSF PCR that must be negative before stopping. Six months of oral acyclovir suppression follows and improves neurodevelopmental outcome after CNS disease.
Congenital syphilis
Maternal treatment decides the workup. Treatment is adequate only if a stage-appropriate penicillin regimen was begun at least 30 days before delivery. No treatment, a non-penicillin drug, undocumented therapy, or treatment within 30 days of delivery leaves the infant at risk. The infant's serum (not cord blood) is tested with the same nontreponemal test used for the mother; treponemal tests are uninterpretable in infants because maternal IgG crosses the placenta.
Clinical signs. Early congenital syphilis causes rhinitis ("snuffles"), a desquamating maculopapular rash including the palms and soles, hepatosplenomegaly, jaundice, lymphadenopathy, anemia or thrombocytopenia, and osteochondritis or periostitis that makes the infant refuse to move a limb (pseudoparalysis). Untreated disease later produces Hutchinson teeth, saddle nose, saber shins, interstitial keratitis, and sensorineural deafness.
| Situation | Evaluation | Treatment |
|---|---|---|
| Proven or highly probable: abnormal exam or infant titer ≥4× maternal | CSF VDRL, cell count, protein; CBC with platelets; long-bone films; others as indicated | IV aqueous penicillin G for 10 days |
| Possible: normal exam, titer <4× maternal, but maternal treatment absent, inadequate, or <30 days before delivery | CSF, CBC, long-bone films | IV aqueous penicillin G for 10 days; alternatively a single IM dose of benzathine penicillin G 50,000 units/kg if the full evaluation is normal and follow-up is certain |
| Less likely: normal exam, titer <4× maternal, adequate penicillin ≥30 days before delivery | None required | Single IM dose of benzathine penicillin G |
Neonatal conjunctivitis and chlamydial pneumonia
| Cause | Onset | Features | Management |
|---|---|---|---|
| Chemical | Day 1 | Mild irritation from prophylaxis (classically silver nitrate) | Resolves in 24–48 hours |
| Neisseria gonorrhoeae | Days 2–5 | Hyperacute purulent discharge, lid edema, chemosis; corneal perforation risk; gram-negative intracellular diplococci | Hospitalize; single dose of ceftriaxone (cefotaxime if hyperbilirubinemic), saline irrigation, look for disseminated infection, test for chlamydia |
| Chlamydia trachomatis | Days 5–14 | Watery to mucopurulent discharge, lid swelling, sometimes pseudomembranes; NAAT of conjunctival scrapings | Oral erythromycin 14 days or azithromycin 3 days; treat the mother and partners |
| Herpes simplex | First 2 weeks | Keratoconjunctivitis ± vesicles | IV acyclovir plus ophthalmology |
Prophylaxis. Erythromycin 0.5% ointment applied soon after birth prevents gonococcal but not chlamydial ophthalmia. Infants of mothers with untreated gonorrhea receive ceftriaxone even without symptoms.
Why chlamydia is treated orally. Topical agents do not clear nasopharyngeal carriage, which seeds pneumonia at 4–12 weeks: an afebrile infant with tachypnea, a repetitive staccato cough, crackles, hyperinflation with interstitial infiltrates, and peripheral eosinophilia; about half had conjunctivitis earlier. Macrolides given in the first weeks of life increase the risk of hypertrophic pyloric stenosis, so parents are told to report projectile vomiting.
Varicella exposure
The dangerous window. When maternal chickenpox begins between 5 days before and 2 days after delivery, the infant receives virus without the protective maternal IgG that takes several days to cross, and severe disseminated neonatal varicella can follow. The infant receives VariZIG as soon as possible (within 10 days; IVIG if VariZIG is unavailable), and IV acyclovir if disease develops.
No VariZIG is needed for maternal zoster or for chickenpox that began more than 5 days before delivery, because antibody has already reached the infant. Maternal infection in the first 20 weeks instead risks congenital varicella syndrome (scarring skin lesions, limb hypoplasia, chorioretinitis, microcephaly).