A systematic review and meta-analysis of the prevalence of human cytomegalovirus shedding in seropositive pregnant women

Abstract

The detection of human cytomegalovirus (HCMV) in an individual's bodily fluid by culture techniques or through HCMV DNA detection by polymerase chain reaction, is known as HCMV shedding. Human cytomegalovirus shedding has the potential to transmit HCMV infection, where an individual can become infected with HCMV through contact with the bodily fluid of another individual containing HCMV. Human cytomegalovirus shedding can occur in primary infection and in non-primary infection for individuals with prior infection (HCMV seropositive). Human cytomegalovirus infection causes few or no symptoms in a pregnant woman, but can cause significant harm to her foetus if congenital CMV (cCMV) infection occurs. The association between HCMV shedding in HCMV seropositive pregnant women and the vertical transmission of HCMV to result in cCMV infection is poorly investigated, challenged by a limited understanding of the distribution of HCMV shedding in HCMV seropositive pregnant women. We systematically reviewed the published literature to describe the prevalence of HCMV shedding in HCMV seropositive women during pregnancy up to delivery. This analysis identified nine studies that met our eligibility criteria. In these studies, the prevalence of HCMV shedding in any bodily fluid of HCMV seropositive women during pregnancy and at delivery ranged from 0% to 42.5%. A meta-analysis, performed on six of the nine studies with suitable sample sizes, estimated a pooled prevalence of 21.5% [95% CI 12.7%,30.3%]. To our knowledge, this is the first review to systematically search the literature to summarise the prevalence of HCMV shedding in HCMV seropositive pregnant women. These estimates can help in the development of disease burden models and therapeutic or preventative strategies against cCMV infection in the context of non-primary maternal HCMV infection.

Keywords: cytomegalovirus; pregnant; prevalence; seropositive; shedding.

FIGURE 1

Flow diagram of the identification of studies for the systematic review. Flow diagram of the identification of studies of the systematic review, adapted from PRISMA 2020 flow diagram for systematic review. Studies were identified according to the search strategy and inclusion criteria developed for the review from three databases: MEDLINE, Embase, and Web of Science Core Collection.

FIGURE 2

Forest plot displaying a random effects meta‐analysis of the prevalence of human cytomegalovirus (HCMV) shedding in any bodily fluid of HCMV seropositive pregnant women on selected studies. Forest plot displaying a random effects meta‐analysis of the prevalence of CMV shedding in any bodily fluid of CMV seropositive pregnant women on selected studies with suitable sample size. Each square represents the prevalence for each study included in the meta‐analysis, placed in position to the corresponding study on the y‐axis and the corresponding prevalence estimate on the y‐axis. The pooled estimate prevalence is marked by a diamond. The length of the line on either side of each square and diamond represents the extent of the prevalence 95% CI. The prevalence estimate and 95% CI for each study and for the pooled estimate are also displayed on the far right, including Higgins I² score for the pooled estimate displayed as I² to analyse heterogeneity across the studies.