Five RCTs (799 women) were included.
Four RCTs reported an estimation of sample size, but none reached the minimum estimated sample size. One RCT did not report adequate allocation concealment. Four RCTs reported analysis on an intention-to-treat basis.
Acyclovir significantly reduced clinical HSV recurrence at the time of delivery (4% versus 15% for controls). The OR was 0.25 (95% CI: 0.15, 0.40). No statistically significant heterogeneity was detected (P=0.19).
Acyclovir significantly reduced Caesarean section delivery for clinical HSV recurrence (4% versus 14.6% for controls). The OR (random-effects model) was 0.30 (95% CI: 0.13, 0.67). Statistically significant heterogeneity was detected (P=0.02). Acyclovir also significantly reduced Caesarean section delivery for any indication (OR 0.61, 95% CI: 0.43, 0.86). No statistically significant heterogeneity was detected (P=0.86).
Acyclovir significantly reduced the detection of HSV at delivery using viral culture (0% versus 5% for controls). The OR (4 RCTs) was 0.11 (95% CI: 0.04, 0.31). No statistically significant heterogeneity was detected (P=0.99).
Acyclovir significantly reduced asymptomatic shedding at delivery. The OR (4 RCTs) was 0.09 (95% CI: 0.02, 0.39). No statistically significant heterogeneity was detected (P=0.94).
Similar results were obtained for clinical recurrence at delivery when analysing only studies with adequate blinding. The results were similar for both dosing regimens of acyclovir and by type of disease. These results were reported.
None of the studies reported any cases of neonatal herpes.
The funnel plot suggested a low possibility of publication bias.