[4] Maternal risk factors for neonatal HSV-1 include: White non-Hispanic race,[9] young maternal age (<25), primary infection in third trimester,[10] first pregnancy, HSV (1&2) seronegativity,[8][11] a discordant partner,[12] gestation <38 weeks,[10] and receptive oral sex in the third trimester.

[13] Neonatal HSV-2 maternal risk factors: Black race,[14] young maternal age (<21),[8][10] a discordant partner, primary or non-primary first episode infection in the third trimester,[15] four or more lifetime sexual partners,[14] lower level of education,[14] history of previous STD, history of pregnancy wastage, first viable pregnancy, and gestation <38 weeks.

[6] Swabs are generally taken from the mouth, nose, throat, eyes, and anus, for HSV culture an PCR.

[4] Other tests include a lumbar puncture and medical imaging of the brain; MRI, CT scan, ultrasound.

[3] Bacterial sepsis, viral hepatitis, and other infections including cytomegalovirus, toxoplasmosis, syphilis, rubella may mimic the disseminated type.

[24] A recent large-scale retrospective study found disseminated NHSV patients least likely to get timely treatment, contributing to the high morbidity/mortality in that group.

[25] Harrison's Principles of Internal Medicine recommends that pregnant women with active genital herpes lesions at the time of labor be delivered by caesarean section.

Approximately 22% of pregnant women in the U.S. have had previous exposure to HSV-2, and an additional 2% acquire the virus during pregnancy, mirroring the HSV-2 infection rate in the general population.

This in part is due to the transfer of a significant titer of protective maternal antibodies to the fetus from about the seventh month of pregnancy.

A study in the United States from 2003 to 2014 using large administrative databases showed increasing trends in incidence of neonatal HSV from 7.9 to 10 cases per 100,000 live births and mortality of 6.5%.

Babies of decreased gestational age and those of African American race had higher incidences of neonatal HSV.

[29] A three-year study in Canada (2000–2003) revealed a neonatal HSV incidence of 5.9 per 100,000 live births and a case fatality rate of 15.5%.