Source:Brown ZA, Wald A, Morrow RA, et al. Effect of serologic status and cesarean delivery on transmission rates of herpes simplex virus from mother to infant.

Investigators from the University of Washington evaluated the risk factors for perinatal transmission of herpes simplex virus (HSV) in a prospective multicenter study between 1982 and 1999. Viral cultures of genital secretions of enrolled pregnant women were performed within 48 hours of delivery. Maternal serologic status for HSV was determined at delivery or antepartum obstetric visit. HSV serology and culture results were used to define the type of maternal infection. Positive culture for HSV-1 or 2 without concurrent HSV antibodies was defined as primary infection; positive HSV culture and heterologous positive HSV type serology was non-primary first-episode (eg, HSV-1 isolate, HSV-2 antibodies); and positive culture with positive homologous serology was defined as reactivation maternal HSV infection (eg, HSV-2 isolate, HSV-2 antibodies). There were 58,362 live births during the study and 18 cases of neonatal HSV infection (1/3,200 live births): 8 by HSV-1 (4 each with primary and reactivation infection) and 10 by HSV-2 (7 with primary or non-primary first episode infection and 3 with reactivation). HSV cultures were obtained within 48 hours of delivery in 69% (40,023) of the women and HSV was isolated in 202 (0.5%). Ten of the 202 HSV-culture-positive women transmitted the infection to their neonate and this was a major risk factor for developing neonatal HSV infection (OR=346; 95% CI, 125–956). Three of 3 women with primary HSV-1 infection, 1 (17%) of 6 with HSV-2 primary infection, 4 (25%) of 16 with non-primary first episode HSV-2 infection, and 2 (18%) of 11 with reactivation HSV-1 infection transmitted the infection to their neonates. None of the 140 women with reactivation HSV-2 infection transmitted the infection to their infants. Of the 202 women with positive cultures, 9 (7.7%) of 117 infants who were delivered vaginally and 1 (1.2%) of 85 who were delivered by C-section developed HSV infection (OR=0.14; 95%, CI, 0.02–1.08; P=.047). Of the 10 HSV-infected infants, 4 were born to 102 women with a history of genital HSV and 6 to the 100 women without such a history. Women without a history of genital HSV were more likely to shed subclinically than those with a history of HSV infection (87 versus 41; P<.001). Lack of maternal antibodies to the homologous virus was associated with an increased risk of neonatal transmission (OR=33.1; 95% CI, 6.5–168).

Little progress has been made to hasten the diagnosis and improve the therapeutic outcome of neonatal HSV infections.1,2 Most clinicians have a high index of suspicion; many newborns are being cultured for HSV and many are empirically treated with acyclovir. However, the diagnosis is still made at about 10 days of age.2 This study clearly demonstrates the protective effect of C-section in mothers with active genital lesions, a confirmation of current recommendations and practice. The data also suggest that a rational use...

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