Congenital Rubella Infection

Summary

 Rubella infection during pregnancy, particularly in the first trimester, can lead to miscarriage or congenital rubella syndrome, characterized by cardiac, auditory, and ocular defects. Universal vaccination and herd immunity remain the most effective preventive measures, and early recognition is essential for counseling and management.

Epidemiology

 Congenital rubella infection is now extremely rare due to widespread maternal immunization. Outbreaks are uncommon in countries with high vaccine coverage. Primary maternal infection poses the greatest risk to the fetus, especially during the first trimester.

Pathogen

Rubella virus, a single-stranded RNA virus, is transmitted via airborne droplets. Vertical transmission occurs transplacentally from an infected mother.

Transmission and Risk

• Maternal infection: Typically via respiratory droplets from close contact.

• Fetal infection: Risk depends on gestational age:

  • 1–12 weeks (organogenesis): Highest risk of congenital rubella syndrome (CRS) and miscarriage.

  • 12–20 weeks: Very low risk.

  • >20 weeks: No documented CRS cases.

Clinical Features

Intrauterine Infection

Miscarriage, preterm birth, and fetal growth restriction, particularly with first-trimester infection.

Congenital Rubella Syndrome (CRS)

Diagnosis

• Maternal/Newborn: PCR for rubella RNA (throat swab, CSF), serology (IgM/IgG), viral culture.

• Fetal: IgM antibody or PCR on chorionic villi or amniotic fluid.

Management

• Maternal infection <16 weeks: Counseling regarding potential maternal-fetal transmission and pregnancy termination.

• Maternal infection >16 weeks: Symptomatic therapy (e.g., antipyretics) and reassurance.

• CRS: Supportive care tailored to individual manifestations and monitoring for late-onset complications.

Prevention

• Immunization of seronegative women prior to pregnancy is the cornerstone of prevention.

• Rubella vaccination is contraindicated during pregnancy due to theoretical teratogenic risk.

• Congenital rubella syndrome is nationally notifiable.
  
  

Antenatal Considerations

• Routine prenatal screening is no longer standard in countries with high vaccine coverage but may include maternal IgG/IgM testing in selected cases.

• First-trimester infections warrant referral to a fetal medicine specialist for counseling and possible prenatal diagnosis via PCR of amniotic fluid.