Global prevalence of herpes simplex virus among pregnant women: a systematic review and meta-analysis

Herpes simplex virus (HSV) infection in pregnancy poses important risks for mothers and newborns. We synthesised global evidence on HSV prevalence in pregnant women, stratified by virus type (HSV‑1, HSV‑2), immunoglobulin class (IgG, IgM), diagnostic method, and biological specimen Herpes simplex virus (HSV) infection during pregnancy poses risks for neonatal transmission, particularly when primary infection occurs near delivery. We synthesized global evidence on HSV markers among pregnant women to inform clinical risk stratification and evidence-based management. We systematically searched PubMed, Embase, Web of Science, and Scopus from January 2000 to June 2024 for observational studies reporting HSV prevalence in pregnant women. Two reviewers independently screened studies, extracted data, and assessed quality using standardized tools. Random-effects meta-analysis was performed on logit-transformed proportions using Python-based statistical tools (due to logistical constraints, Python libraries including pandas, numpy, and scipy were utilized for all meta-analytical computations), with heterogeneity quantified using I² statistics and prediction intervals. Temporal trends were explored via meta-regression. This review was registered on PROSPERO (CRD42023395041). We identified 200 studies comprising 120,536 pregnant women from 56 countries. HSV-1 IgG seroprevalence was 79.1% (95% CI: 73.3–83.9%; I² = 97.0%) across 48 studies, indicating widespread prior exposure. HSV-2 IgG seroprevalence was 28.6% (95% CI: 25.6–31.9%; I² = 97.7%) across 150 studies, with marked geographic variation (6–55%). Acute infection markers were uncommon: HSV-1 IgM 1.9% (95% CI: 1.0–3.6%) and HSV-2 IgM 4.7% (95% CI: 2.8–7.9%). PCR detected HSV DNA in 9.4% of cervico-vaginal specimens but 0% of amniotic fluid samples (4,383 tests). Meta-regression revealed declining HSV-1 (− 14 points/decade, p = 0.034) and rising HSV-2 (+ 7.7 points/decade, p = 0.016). Low IgM seroprevalence suggests primary HSV infection during pregnancy is likely uncommon and High HSV IgG seroprevalence reflects widespread prior exposure and indicates protective maternal immunity, more than an infection risk. based on our findings Management should remained focused on: (1) suppressive antivirals from 36 weeks for women with known recurrent genital herpes; (2) recognizing primary infection during pregnancy; and (3) clinical assessment at delivery. Our findings are not consistent with Universal screening and do not support the routine use of PCR testing for amniotic fluid. Prior estimates of HSV seroprevalence in pregnant women are fragmented and region-specific, limiting global understanding of disease burden. Uncertainty exists regarding the true incidence of primary HSV infection during pregnancy (the highest-risk scenario for neonatal transmission), and whether universal serologic screening should be recommended. Guidelines from WHO, CDC, and ACOG exist but lack comprehensive evidence synthesis specific to pregnant populations. This is the largest global meta-analysis (200 studies, 56 countries, > 120,000 pregnant women) establishing that HSV-1 seroprevalence is 79% and HSV-2 is 29%, with marked geographic variation. Critically, we demonstrate that acute infection markers (IgM) are rare (HSV-1: 1.9%; HSV-2: 4.7%), confirming that primary infection during pregnancy is likely uncommon. We provide a comprehensive evidence that amniotic fluid PCR testing has limited clinical utility (0% positivity across 4,383 samples), and temporal trends show declining HSV-1 but rising HSV-2 globally. These findings directly support evidence-based guidelines recommending against universal HSV screening in pregnancy. High seroprevalence indicates protective immunity, rather than infection risk. Clinical practice should focus on suppressive antivirals for women with known recurrent genital herpes, clinical recognition of primary infection, and assessment at delivery more than serology alone. For policy and research, our data highlight the need for genital-specific HSV-1 surveillance (not serology), as distinct trends in genital versus oral acquisition may impact prevention strategies in younger, seronegative populations.