Obstetric Topic 37. Infectious diseases in pregnancy. Viral infections

I. TORCH Viral Infections

Rubella

• Virus: rubella virus; TORCH "R"; fetal risk is highest in 1st trimester.
• Maternal effects: mild fever, maculopapular rash, lymphadenopathy, arthralgia/arthritis.
• Fetal effects: congenital rubella syndrome → PDA, cataract/blindness, deafness, microcephaly/intellectual disability.
• Diagnosis: serology (IgM/seroconversion) and PCR if needed.
• Treatment: supportive; no fetal curative treatment.
• Prevention: MMR/MMRV live vaccine before pregnancy or postpartum; contraindicated during pregnancy.

Cytomegalovirus

• CMV: TORCH "C"; most common congenital viral infection.
• Maternal effects: usually asymptomatic or mild flu/mononucleosis-like illness.
• Fetal effects: stillbirth, IUGR, microcephaly, periventricular calcifications, chorioretinitis and sensorineural hearing loss.
• Diagnosis: serology; fetal diagnosis by amniotic-fluid PCR when indicated.
• Treatment: no standard fetal-specific treatment; symptomatic newborns may receive antivirals in specialist care.
• Prevention: hand hygiene and avoidance of saliva/urine exposure from young children; no vaccine.

Varicella-Zoster Virus

• VZV: TORCH "other"; primary infection causes chickenpox.
• Maternal effects: fever and vesicular rash; pneumonia is the major severe complication in pregnancy.
• Fetal effects: congenital varicella syndrome with limb hypoplasia, eye defects and CNS defects.
• Peripartum infection near delivery → severe neonatal varicella risk.
• Diagnosis: clinical rash; PCR from lesion if uncertain.
• Treatment: acyclovir/valacyclovir; IV acyclovir for pneumonia or severe disease.
• Post-exposure prophylaxis: VZIG/VariZIG for susceptible pregnant patient after significant exposure.
• Prevention: varicella vaccine before pregnancy or postpartum; live vaccine contraindicated during pregnancy.

Herpes Simplex Virus

• HSV-2 is classic for genital herpes; TORCH "H"; transmission is mainly intrapartum.
• Maternal effects: painful grouped genital vesicles/ulcers, dysuria, tender nodes; recurrent disease may be mild.
• Fetal/neonatal effects: prematurity/stillbirth, vesicular skin lesions, keratoconjunctivitis/blindness, encephalitis/meningoencephalitis, disseminated disease.
• Diagnosis: PCR or viral culture from lesion; Tzanck smear is older/less specific.
• Treatment: acyclovir/valacyclovir.
• Prevention: suppressive acyclovir/valacyclovir from 36 weeks for recurrent genital HSV.
• Delivery: cesarean if active genital lesions or prodromal symptoms at labor; vaginal delivery acceptable if no lesions/prodrome.

II. Other Important Viral Infections

Parvovirus B19

• Virus: parvovirus B19; TORCH "other".
• Maternal effects: often mild or asymptomatic; rash, fever, arthralgia.
• Fetal effects: severe fetal anemia → high-output heart failure → hydrops fetalis or fetal death.
• Diagnosis: maternal IgM/IgG serology; PCR when needed.
• Treatment: intrauterine blood transfusion for severe fetal anemia/hydrops; otherwise monitoring.

Hepatitis B Virus

• Transmission: mainly peripartum exposure to infected blood/body fluids.
• Neonatal effect: chronic HBV infection.
• Diagnosis/screening: HBsAg screening at first prenatal visit.
• Maternal treatment: supportive for acute disease; tenofovir may be used for very high viral load to reduce transmission.
• Delivery: cesarean is not indicated solely for HBV.
• Newborn prevention: HBIG + hepatitis B vaccine soon after birth, then complete vaccine series.
• Breastfeeding: allowed if newborn receives appropriate immunoprophylaxis.

Human Immunodeficiency Virus

• Transmission: transplacental, intrapartum and breastfeeding.
• Without prophylaxis: vertical transmission about 15-25%; effective ART markedly lowers risk.
• Diagnosis/screening: routine HIV Ag/Ab screen early in pregnancy; RT-PCR/viral load for monitoring.
• Treatment: combination antiretroviral therapy for mother; neonatal ART prophylaxis after birth.
• Delivery: viral-load based; vaginal delivery if suppressed, scheduled cesarean if viral load high or unknown near delivery.
• Prevention: routine maternal screening, ART, avoid invasive intrapartum procedures when possible, and avoid breastfeeding in many European/Hungarian exam settings.