Background Breach of neonatal skin by obstetric procedures during delivery increases risk of neonatal herpes among infants of women with genital HSV infections. We hypothesised that knowledge of genital HSV infection by clinical history or antibody tests (GH/HSV-2) prior to delivery would result in reduced use of invasive obstetric procedures, and we explored whether use of invasive procedures in infected women on suppressive antiviral therapy was similar to use in women without infection.

Methods We reviewed 750 consecutive deliveries at an academic medical center in 2006; routine prenatal testing included HSV-1 and HSV-2 serostatus. The primary outcome was a composite of invasive delivery procedures (fetal scalp electrodes, artificial rupture of membranes, intrauterine pressure catheter, vacuum extraction or forceps extraction) among women with vs without GH/HSV-2. Women with planned c-sections, multiple gestation pregnancy, or genital herpes lesions at term were excluded.

Results 453 women, including 35 with a history of genital herpes (24 with HSV-2, 11 with HSV-1) and 59 with HSV-2 antibody but no history of genital herpes, were included in the analysis. Of the 94 women with GH/HSV-2, 56 (59.6%) received suppressive antiviral therapy. Among the 38 women with GH/HSV-2 not on suppressive therapy, 15 (39.5%) had an invasive obstetric procedure at delivery compared with 204 (57%) of 359 women without GH/HSV-2 (OR=0.50; 95% CI: 0.25 to 0.98). In contrast, no difference in unplanned c-sections was observed by GH/HSV-2 status (29% vs 28%). Among the 56 women with GH/HSV-2 treated with antiviral therapy, the risk of invasive procedures was similar to that of women without GH/HSV-2, 62.5% vs 57% (OR=1.27; 95% CI 0.71 to 2.26).

Conclusion Women with known genital herpes or HSV-2 positivity are less likely to undergo invasive procedures that increase the risk of neonatal herpes. However, obstetricians do not appear to avoid these procedures in women who are on suppressive therapy. These data suggest physicians who know their patients' HSV-2 status in pregnancy alter their behaviour to maintain the integrity of neonatal skin. Given the frequency of breakthrough HSV-2 shedding on suppressive antiviral therapy, and the occurrence of neonatal herpes in infants born to women on suppressive therapy, the high frequency of invasive procedure use among women on antiviral therapy is concerning.