Updated 01/18/2006 by Juliana Leite, MD

Original text 05/27/1999 Philippe Jeanty, MD, PhD & Sandra R Silva, MD

Synonyms: None.

Definition: Prenatal infection by the herpes simplex virus type II, rarely the type I.

Incidence: Unknown.

Etiology/Pathogenesis: Transplacental or transcervical passage of the virus. Almost all neonatal herpes simplex virus infections are the results of a first-episode maternal infection near the time of labour, when the birth occurs before the development of protective maternal antibodies. It is clear that the majority of newborns acquire the virus by contact with infected genital secretions. Since the majority of cases of first episode genital herpes during pregnancy are asymptomatic or unrecognized in 60% to 80% of women, the prevention of neonatal transmission will depend upon the identification of the HSV serologically discordant couple. The herpes simplex type I transforms the HB-1 human cell line by association with the human gene for adenylate kinase-1 (on chromosome 9).Women with primary genital herpes simplex infection lesions (symptomatic or asymptomatic) who deliver vaginally have a high risk (33-50%) of transmitting infection to their neonates. With recurrence disease, the risk of transmission during a vaginal delivery is much lower (<2-5%).

Diagnosis: Growth restriction, microcephaly, hydranencephaly, cerebellar necrosis, chorioretinitis, cataract, and microphthalmia. Hepatosplenomegaly can also be present.

Genetic anomalies: None.

Associated anomalies: Inguinal hernias, aplasia cutis.

Differential diagnosis: Other TORCH infections.

Recurrence risk: Unknown; no sibs have been reported to have been infected.

Prognosis: A majority of these babies are born prematurely. There is a high mortality and morbidity rates, even though an effective antiviral therapy is now available.

Management: Isolation of the virus in amniotic fluid culture does not necessarily mean infection of the fetus. Treatment with acyclovir and vidarabine may be attempted. Studies of acyclovir use among pregnant women suggest that acyclovir treatment orally, near term, reduces the rate of abdominal deliviery in women who have frequent recurrences because of a decrease on the incidence of active lesions at delivery. Cesarean delivery is indicated for all women with active genital lesions at the time of the delivery.

Prevention: Couples should be educated about the natural history of genital herpes simplex infection. Susceptible pregnant women should avoid sexual contact during the last 6-8 weeks of gestation if they partners have active genital infection.

 
References
1: Nahmias AJ.Neonatal HSV infection Part I: continuing challenges. Herpes 2004;11(2):33-7
2: Rouse DJ, Stringer JS. An appraisal of screening for maternal type-specific herpes simplex virus antibodies to prevent neonatal herpes. Am J Obstet Gynecol 2000;183(2):400-6
3: Brown ZA. HSV-2 specific serology should be offered routinely to antenatal patients. Rev Med Virol 2000;10(3):141-4