What complication is most likely for a newborn whose mother had varicella-zoster virus shortly before delivery?

When a mother is infected with varicella-zoster virus (VZV) shortly before delivery, the most significant concern for the newborn is primarily related to the potential for neonatal varicella. This infection can lead to pneumonia in the newborn due to the mother's active chickenpox during the perinatal period. Neonatal varicella can be particularly severe and is associated with risks of complications, including pneumonia, which is a critical respiratory complication that can occur due to the maternal viral load being high just before and at the time of delivery.

While other complications can arise from maternal infection with VZV, such as CNS defects or limb anomalies, these are generally less directly linked to the timing of the infection compared to the risk of pneumonia, which is more immediate and severe in terms of neonatal impacts. Pneumonia may develop as the newborn's immune system is immature and they are exposed to the virus during delivery or shortly after birth. The presence of varicella lesions on the newborn, if they appear, can indicate potential varicella infection, further complicating the clinical picture and supporting the likelihood of pneumonia occurring as a critical complication in this scenario.