Chickenpox in Pregnancy

Pregnant women in the tropics like India are more susceptible to varicella zoster infection due to the lower seroprevalence of varicella as compared to temperate regions. Seronegative pregnant women are highly susceptible following a significant exposure owing to the high secondary attack rate of the virus. Fetal transmission could happen transplacentally while neonatal transmission occurs through close contact post partum. Maternal VZV infection could be severe (particularly varicella pneumonia) with high mortality if untreated. Congenital varicella syndrome has an incidence of about 1-2% and is more likely if maternal symptoms occur between 5th and 24th week of pregnancy. Susceptible pregnant women with a significant contact should be administered VZIG not later than 10 days of exposure. Women presenting with the typical rash of VZV infection should be prescribed oral aciclovir. The mainstay of diagnosis of fetal varicella syndrome is detailed ultrasound scanning starting 4 weeks after the onset of maternal rash. Prenatal diagnosis of varicella can be achieved by varicella PCR of the amniotic fluid at least 6 weeks after maternal infection. However, presence of the virus in the amniotic fluid does not necessarily imply progression to fetal varicella syndrome. If the mother contracts primary infection at term, her delivery should be delayed by at least 5-7 days after the onset of the rash if possible. Neonatal varicella zoster immunoglobulin should be administered to prevent neonatal infection if delivery cannot be postponed. Obstetrician should be aware of the prophylactic and treatment strategies in the event of exposure/infection.