Intrauterine infection with varicella zoster virus after maternal varicella, N Engl J Med. 1986 Jun 12;314(24):1542-1546.) percent-had neonates with congenital varicella syndrome. he highest risk was between 13 and 20 weeks, during which time seven of 351 exposed fetuses-2 percent-had evidence of congenital varicella. Mter 20 weeks' gestation, the researchers found no clinical evidence of congenital infection. Ahn and colleagues (2016) recently described similar findings. hat said, sporadic reports have described CNS abnormalities and skin lesions in fetuses who developed congenital varicella in weeks 21 to 28 of gestation (Lamont, 2011 a; Marin, 2007).
If the fetus or neonate is exposed to active infection just before or during delivery, and therefore before maternal antibody has been formed, the newborn faces a serious threat. Attack rates range from 25 to 50 percent, and mortality rates approach 30 percent. In some instances, neonates develop disseminated visceral and CNS disease, which is commonly fatal. For this reason, varicella-zoster immune globulin (VZIG) should be administered to neonates born to mothers who have clinical evidence of varicella 5 days before and up to 2 days ater delivery.
Maternal varicella is usually diagnosed clinically. Infection may be confirmed by NAA T of vesicular fluid, which is very sensitive. The virus may also be isolated by scraping the vesicle base during primary infection and performing a Tzanck smear, tissue culture, or direct luorescent antibody testing. Congenital varicella may be diagnosed using NAA T analysis of amnionic luid, although a positive result does not correlate well with the development of congenital infection (Mendelson, 2006). A detailed anatomical sonographic evaluation performed at least 5 weeks after maternal infection may disclose abnormalities, but the sensitivity is low (Mandelbrot, 2012).
Maternal Viral Exposure. Several aspects of maternal VZV exposure and infection in pregnancy afect management. Exposed gravidas with a negative history for chickenpox should undergo VZV serological testing. At least 70 percent of these women will be seropositive, and thus immune. Exposed pregnant women who are susceptible (seronegative) should be given varicella-zoster immune globulin (VariZIG). Although best given within 96 hours of exposure, its use is approved for up to 10 days to prevent or attenuate varicella infection (Centers for Disease Control and Prevention, 2012, 2013d). Passive immunization appears to be highly efective Qespersen, 2016). In women with known history of varicella, VariZI G is not indicated.
Maternal Infection. Any patient dianosed with primay varicella inection or herpes zoster should be isolated rom pregnant women.
Because VZV pneumonia often presents with few symptoms, a chest radiograph is recommended by many. Most women require only supportive care, but those who require intravenous (IV) luids and especially those with pneumonia are hospitalized. IV acyclovir therapy is given to women requiring hospital ization-500 mg/mror 10 to 15 mg/kg every 8 hours.
Vaccination. An attenuated live-virus vaccine is recommended for nonpregnant adolescents and adults with no history of vari cella. Two doses of Varivax are given 4 to 8 weeks apart, and the seroconversion rate is 98 percent (Marin, 2007). Importantly, vaccine-induced immunity diminishes over time, and the (Chaves, 2007).