Systematic review: fetal death reporting and risk in Zika‐affected pregnancies

Abstract

Objectives Zika virus is linked to several adverse pregnancy outcomes. We assessed whether Zika infection during pregnancy is associated with increased risk of foetal death (miscarriage, stillbirth, abortion) and whether there is incomplete reporting of such deaths. Methods We searched PubMed, Embase, CINAHL, Web of Science and LILACS for studies reporting Zika‐affected completed pregnancies (ending in foetal death or live birth), excluding studies whose aim required live birth. Studies ‘allowed’ foetal death if their populations were defined to encompass both live births and foetal deaths, regardless of whether deaths were actually found. Two authors independently extracted data and assessed study quality. Foetal death absolute and relative risks in Zika‐affected vs. unaffected pregnancies were calculated. Results We found 108 reports including 24 699 completed, Zika‐affected pregnancies. The median absolute risk in 37 studies of completed, Zika‐affected pregnancies was 6.3% (IQR 3.2%, 10.6%) for foetal death and 5.9% (IQR 0%, 29.1%) for non‐fatal adverse outcomes (e.g. microcephaly). More studies allowed non‐fatal adverse outcomes (95%) than foetal death (58%). Of studies which allowed them, 94% found at least one foetal death. In 37% of reports, it was unknown whether foetal deaths were allowed. Only one study had sufficient data to estimate a foetal death relative risk (11.05, 95% CI 3.43, 35.55). Conclusions Evidence was insufficient to determine whether foetal death risk is higher in Zika‐affected pregnancies, but suggests quality of foetal death reporting should be improved, including stating whether foetal deaths were found, how many, and at what gestational ages, or justifying their exclusion.

Analysis of Genomic Copy Number Variation in Miscarriages During Early and Middle Pregnancy

“…The causes of spontaneous miscarriage include endocrine factors (Arredondo and Noble, 2006), reproductive tract malformation (Venetis et al, 2014), infectious factors (Leisher et al, 2021), immune factors (Muyayalo et al, 2018), alcohol exposure (Sundermann et al, 2021), genetic factors (Lan et al, 2021) and some other factors that have not been clarified yet. Despite continuous medical advances, spontaneous abortion during early and middle pregnancy is still an important health problem.…”

Zika virus infection in pregnant women and their children: A review

“…While the first and second trimesters of pregnancy represent the highest foetal risk [37,46], ZIKV infections occurring later in pregnancy have also been linked with adverse outcomes including intrauterine growth restriction and foetal loss [35,47]. Data from several studies showed an overall rate of foetal loss of 1-4% among pregnant women with confirmed ZIKV infection [11,38], and 3 to 22% risk of perinatal death in Zika-affected pregnancies [48]. A study in Brazil reported a four-fold excess neonatal mortality in infants born to ZIKV positive mothers compared to negative cases [49].…”

Microcephaly prevalence after the 2015 to 2016 Zika outbreak in Tangará da Serra, Brazil: a population-based study

“…The prevalence of microcephaly in stillbirths is challenging to determine in Brazil and other Latin American countries because postmortem studies are not widely available in medical facilities. However, a recent meta-analysis has estimated the median absolute risk for fetal mortality in 37 studies of Zika-affected pregnancies as 6.3% (IQR 3.2%–10.6%) [28] .…”