Observational studyBMC pregnancy and childbirth2025
Zika in Infants and Pregnancy (ZIP) study: results from a prospective international cohort study of prenatal Zika virus infection and adverse fetal and infant outcomes.
Observational study in BMC pregnancy and childbirth, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT02856984 (International Prospective Observational Cohort Study of Zika in Infants), which is not on this map. Cited by 1 paper.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
International Prospective Observational Cohort Study of Zika in Infants
Who cites it
1 citing paper in PubMed.
- Proof-of-Concept Machine Learning Framework for Arboviral Disease Classification Using Literature-Derived Synthetic Data: Methodological Development Preceding Clinical Validation.Healthcare (Basel, Switzerland) · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
35 authors.
Funding
Abstract
backgroundBefore Zika virus (ZIKV) infections were observed in the Americas, an association between ZIKV and microcephaly or other congenital malformations was not well documented. Initial reports suggested strong associations between ZIKV and congenital malformations, but plausible estimates of causal effects from prospective studies with adequate sample size and covariate data were few.
methodsFrom 2016-2018, the Zika in Infants and Pregnancy (ZIP) study enrolled pregnant people before 18 weeks gestation or with confirmed symptomatic ZIKV in a prospective cohort across 10 sites in South and Central America, and in Puerto Rico. Pregnancies were followed monthly through delivery and 6 weeks postpartum. Infants were followed quarterly to age 12 months. Prespecified co-primary analyses evaluated the associations between a composite endpoint of adverse fetal, neonatal, and infant outcomes with intrauterine ZIKV exposure overall and with symptomatic intrauterine ZIKV exposure. Secondary analyses separately evaluated the association of intrauterine ZIKV exposure with individual components of the primary endpoint.
resultsSix thousand one hundred pregnant participants were included in the primary analysis, including 61 with ZIKV infection during pregnancy confirmed by a ZIKV-specific RNA test. For the primary analyses, the relative risk (RR) for the composite endpoint associated with any ZIKV exposure was 1.64 (95% CI: 0.65, 4.13) and with symptomatic ZIKV exposure 1.08 (95% CI: 0.15, 7.64). Sensitivity analyses provided similar results. Secondary analyses showed significant adjusted RRs [95% CI] for stillbirth (4.28 [1.39, 13.21]), infant death within six weeks (6.20 [1.08, 35.60], and fetal loss before 20 weeks (3.72 [1.82, 7.59]).
conclusionsThe ZIP study identified an elevated but not statistically significant risk of the primary composite outcome with intrauterine ZIKV exposure, and a significantly increased risk of some adverse fetal and infant outcomes with intrauterine ZIKV exposure in secondary analyses. Fewer than expected infections observed during pregnancy, coincident with a waning epidemic, limited study power to evaluate risk. Combining data from multiple cohorts for future meta-analysis may better define the risks of intrauterine ZIKV exposure.
trial registrationNCT02856984. Registered August 5, 2016. Retrospectively registered.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.