Vaginal bleeding in pregnancy and adverse clinical outcomes: a systematic review and meta-analysis

Abstract

Background: Vaginal bleeding during pregnancy has been recognised as a significant risk factor for adverse pregnancy outcomes. This study aimed to investigate the association between vaginal bleeding during the first trimester of pregnancy and clinical adverse effects using a systematic review and meta-analysis.

Methods: Databases of Scopus, Web of Science, PubMed (including Medline), Cochrane Library and Science Direct were searched until June of 2023. Data analysis using statistical test fixed- and random-effects models in the meta-analysis, Cochran and meta-regression. The quality of the eligible studies was assessed by using the Newcastle–Ottawa Scale checklist (NOS).

Results: A total of 46 relevant studies, with a sample size of 1,554,141 were entered into the meta-analysis. Vaginal bleeding during the first trimester of pregnancy increases the risk of preterm birth (OR: 1.8, CI 95%: 1.6–2.0), low birth weight (LBW; OR: 2.0, CI 95%: 1.5–2.6), premature rupture of membranes (PROMs; OR: 2.3, CI 95%: 1.8–3.0), abortion (OR: 4.3, CI 95%: 2.0–9.0), stillbirth (OR: 2.5, CI 95%: 1.2–5.0), placental abruption (OR: 2.2, CI 95%: 1.4–3.3) and placenta previa (OR: 1.9, CI 95%: 1.5–2.4).

Conclusions: Vaginal bleeding in the first trimester of pregnancy is associated with preterm birth, LBW, PROMs, miscarriage, stillbirth, placental abruption and placenta previa. Therefore, physicians or midwives need to be aware of the possibility of these consequences and manage them when they occur.

PLAIN LANGUAGE SUMMARY

Vaginal bleeding in the first trimester of pregnancy increases the relative risk of preterm birth, low birth weight, premature rupture of membranes, abortion, stillbirth, placental abruption and placenta previa.

Keywords:

• Uterine haemorrhage
• vaginal bleeding
• pregnancy complications
• first pregnancy trimester
• meta-analysis

Acknowledgements

The authors would like to thank the Deputy of Research and Technical Information of Shahroud University of Medical Sciences for supporting this research.

Ethics approval

This study was approved by Shahroud University of Medical Sciences (Ethical code: IR.SHMU.REC.1399.025).

Contributions to authorship

Arezoo Karimi: Data collection, data extraction, writing the manuscript, approval of the final version to be published;

Kourosh Sayehmiri: Data analysis and interpretation and quality appraisals, approval of the final version to be published;

Salman Daliri: Data collection, data extraction, writing the manuscript, approval of the final version to be published;

Mojtaba Vaismoradi: Writing the manuscript, critical interpretation of content, approval of the final version to be published;

Mostafa Dianatinasab: Writing the manuscript, critical interpretation of content; approval of the final version to be published.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article [and/or] its Supplementary materials.

Additional information

Funding

This research received no financial support for conducting and publication of results. This study was approved by Shahroud University of Medical Sciences (Ethical code: IR.SHMU.REC.1399.024).