What should be done if a pregnant woman has a negative IgG titer for VZV following exposure?

If a pregnant woman has a negative IgG titer for Varicella-Zoster Virus (VZV) following exposure, the most appropriate step is to administer Varicella-Zoster Immunoglobulin (VZIG) within 96 hours of exposure. This immunoglobulin provides passive immunity and can help prevent or lessen the severity of chickenpox if administered promptly.

A negative IgG titer indicates that the woman is not immune to VZV, making her susceptible to infection. Given the risks associated with varicella infection during pregnancy, which can lead to complications such as congenital varicella syndrome or pneumonia, prompt administration of VZIG is crucial.

While antiviral therapy can be effective in treating varicella in non-pregnant individuals or those at high risk, it is not the standard immediate course of action after exposure in a pregnant woman without confirmed infection. Instead, the focus should be on providing prophylaxis through VZIG. Routine prenatal care remains important but does not address the acute risk of VZV infection following known exposure. Encouraging bed rest does not provide any specific benefit related to the exposure or infection risk. Thus, the administration of VZIG is the critical response in this scenario.