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

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.
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.
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).
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

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

白细胞介素-6（Interleukin-6, IL-6）是一种促炎细胞因子（pro-inflammatory cytokine），在早产（preterm birth, PTB）的发生发展中发挥重要作用。此前已有多项荟萃分析探讨了IL-6与早产之间的关联，但尚未得出明确结论。本更新版荟萃分析旨在通过对比正常分娩组与早产组的IL-6水平，明确二者之间的关联。

本研究检索了PubMed、Embase及Cochrane图书馆自建库至2020年2月18日收录的前瞻性队列研究。研究的主要结局指标为IL-6与早产的关联，次要结局指标为IL-6与自发性早产的关联。

最终纳入9项研究，共涉及1904名受试者。总体而言，不同样本类型（母体血液、羊水及宫颈阴道分泌物）中的IL-6水平与早产存在显著关联（标准化均数差[standard mean difference, SMD]：0.86，95%置信区间[confidence interval, CI]：0.32~1.39，p<0.001）。进一步亚组分析显示，仅羊水（SMD：1.87，95%CI：0.82~2.93，p<0.001）及宫颈阴道分泌物中的IL-6水平与早产存在显著关联，而母体血液中的IL-6水平与早产无显著关联（SMD：-0.11，95%CI：-0.57~0.34，p=0.623）。此外，IL-6水平与自发性早产亦存在显著关联（SMD：1.57，95%CI：0.18~2.95，p<0.001）。

基于现有证据，羊水及宫颈阴道分泌物中的IL-6或可用于早产的预测。

核心要点
基于现有证据，羊水及宫颈阴道分泌物中的IL-6或可用于早产的预测。
基于现有证据，羊水及宫颈阴道分泌物中的IL-6或可用于早产的预测。