What are the effects of parvovirus B19 infection in pregnancy?

Parvovirus B19 (which causes 'slapped cheek'/fifth disease) can infect the fetus and suppress fetal red cell production, causing severe fetal anaemia.

This can lead to hydrops fetalis (high-output heart failure) and fetal death, especially with infection in the first half of pregnancy. Management involves fetal monitoring (for anaemia/hydrops) and intrauterine blood transfusion if needed.

Clinical relevance. Recognising that parvovirus B19 causes fetal anaemia/hydrops directs fetal surveillance and intrauterine transfusion, often allowing recovery.

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Parvovirus B19 in pregnancy

Parvovirus B19 can cause fetal anaemia and hydrops.

The virus

• Parvovirus B19 - causes erythema infectiosum ('slapped cheek'/fifth disease) in children; transmitted via respiratory droplets.

Fetal effects

• The virus is tropic for fetal red cell precursors - suppressing erythropoiesis -> severe fetal anaemia.
• Severe anaemia -> high-output cardiac failure -> hydrops fetalis, and potentially fetal death/miscarriage (highest risk with infection in the first half of pregnancy).
• Does not typically cause congenital malformations (unlike rubella/CMV).

Management

• Fetal surveillance after maternal infection - ultrasound for hydrops and middle cerebral artery Doppler for fetal anaemia.
• Intrauterine (fetal) blood transfusion for severe fetal anaemia (often allowing recovery, as it is usually self-limiting).