Association between interleukin-6 and preterm birth: a meta-analysis

Abstract

Background

Interleukin (IL)-6 is a pro-inflammatory cytokine that plays an important role in preterm birth (PTB), Several meta-analyses investigated the association between IL-6 and PTB, but definitive conclusion has not yet been achieved. This updated meta-analysis aimed to ascertain the association between IL-6 and PTB by examining IL-6 levels in both normal birth and PTB groups.

Material and methods

Prospective cohort studies were retrieved in PubMed, Embase, and the Cochrane library from their inception until 18 February 2020. The primary outcome was the association between IL-6 and PTB, and secondary outcomes were the association between IL-6 and spontaneous PTB.

Results

Nine studies involving 1904 patients were included. Overall, IL-6 from different sample types (maternal blood, amniotic fluid and cervicovaginal fluid) was associated with PTB (standard mean difference [SMD]: 0.86, 95% confidence interval [CI]: 0.32 to 1.39, p < 0.001). Furthermore, the association was significant for IL-6 only in amniotic fluid (SMD: 1.87, 95%CI: 0.82 to 2.93, p < 0.001) and cervicovaginal fluid (SMD: 0.46, 95%CI: 0.09 to 0.84, p = 0.022), but not significant in maternal blood (SMD: −0.11, 95%CI: −0.57 to 0.34, p = 0.623). In addition, IL-6 was also associated with spontaneous PTB (SMD: 1.57, 95% CI: 0.18 to 2.95, p < 0.001).

Conclusions

Based on the available evidence, IL-6 in amniotic fluid and cervicovaginal fluid might be useful for predicting preterm birth.

KEY MESSAGES

• Based on the available evidence

• IL-6 in amniotic fluid and cervicovaginal fluid might be useful for predicting preterm birth

Keywords:

• Preterm birth
• interleukin-6
• amniotic fluid
• cervicovaginal fluid
• Meta-Analysis

Acknowledgements

Not applicable.

Authors’ contributions

YC and XC: study design, data collection and analysis, statistical analysis, and manuscript drafting. WL: study design, and data collection and analysis. YS and SL: data collection. YC: manuscript revision. XC: study design and critical revision of the manuscript. WL: study design and manuscript revision. YC and WL contributed equally to this study. All authors have read and approved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

The study was supported by Natural Science Foundation of Tianjin (General Program), No. 20JCYBJC01400, and (Youth programs), No. 20JCQNJC01750.