Brown ZA, Wald A, Morrow RA, Selke S, Zeh J, Corey L. JAMA 2003;289:203-209.
Comment in:
JAMA. 2003;289:2208; author reply 2208-2209.
JAMA. 2003;289:2208; author reply 2208-9.

CONTEXT: Neonatal herpes most commonly results from fetal exposure to infected maternal genital secretions at the time of delivery. The risk of transmission from mother to infant as it relates to maternal herpes simplex virus (HSV) serologic status and exposure to HSV in the maternal genital tract at the time of labor has not been quantified. Furthermore, no data exist on whether caesarean delivery, the standard of care for women with genital herpes lesions at the time of delivery, reduces HSV transmission. OBJECTIVE: To determine the effects of viral shedding, maternal HSV serological status and delivery route on the risk of transmission of HSV from mother to infant. DESIGN: Prospective cohort of pregnant women enrolled between January 1982 and December 1999. SETTINGS: A university medical centre, a US Army medical centre, and 5 community hospitals in Washington State. PATIENTS: A total of 58 362 pregnant women, of whom 40 023 had HSV cultures obtained from the cervix and external genitalia and 31 663 had serum samples tested for HSV. MAIN OUTCOME MEASURE: Rates of neonatal HSV infection. RESULTS: Among the 202 women from whom HSV was isolated at the time of labour, 10 (5%) had neonates with HSV infection (odds ratio [OR], 346; 95% confidence interval [CI], 125-956 for neonatal herpes when HSV was isolated versus not isolated). Caesarean delivery significantly reduced the HSV transmission rate among women from whom HSV was isolated (1 [1.2%] of 85 caesarean versus 9 [7.7%] of 117 vaginal; OR, 0.14; 95% CI, 0.02-1.08; P = 0.047). Other risk factors for neonatal HSV included first-episode infection (OR, 33.1; 95% CI, 6.5-168), HSV isolation from the cervix (OR, 32.6; 95% CI, 4.1-260), HSV-1 versus HSV-2 isolation at the time of labour (OR, 16.5; 95% CI, 4.1-65), invasive monitoring (OR, 6.8; 95% CI, 1.4-32), delivery before 38 weeks (OR, 4.4; 95% CI, 1.2-16), and maternal age less than 21 years (OR, 4.1; 95% CI, 1.1-15). Neonatal HSV infection rates per 100 000 live births were 54 (95% CI, 19.8-118) among HSV-seronegative women, 26 (95% CI, 9.3-56) among women who were HSV-1-seropositive only, and 22 (95% CI, 4.4-64) among all HSV-2-seropositive women. CONCLUSION: Neonatal HSV infection rates can be reduced by preventing maternal acquisition of genital HSV-1 and HSV-2 infection near term. They can also be reduced by caesarean delivery and limiting the use of invasive monitors among women shedding HSV at the time of labour.