Association between interleukin-6 and preterm birth: a meta-analysis.
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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.
SUBMITTER: Chang Y
PROVIDER: S-EPMC10836263 | biostudies-literature | 2023
REPOSITORIES: biostudies-literature
Publications
Association between interleukin-6 and preterm birth: a meta-analysis.
Chang Ying Y Li Wen W Shen Yongmei Y Li Shanshan S Chen Xu X
Annals of medicine 20231127 2
<h4>Background</h4>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.<h4>Material and methods</h4>Prospective cohort studies were retrieved in PubMed, Embase, and the Cochrane l ...[more]
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Project description:Because of the role of inflammation in preterm birth (PTB), polymorphisms in and near the interleukin-6 gene (IL6) have been association study targets. Several previous studies have assessed the association between PTB and a single nucleotide polymorphism (SNP), rs1800795, located in the IL6 gene promoter region. Their results have been inconsistent and SNP frequencies have varied strikingly among different populations. We therefore conducted a meta-analysis with subgroup analysis by population strata to: (1) reduce the confounding effect of population structure, (2) increase sample size and statistical power, and (3) elucidate the association between rs1800975 and PTB.We reviewed all published papers for PTB phenotype and SNP rs1800795 genotype. Maternal genotype and fetal genotype were analyzed separately and the analyses were stratified by population. The PTB phenotype was defined as gestational age (GA) < 37 weeks, but results from earlier GA were selected when available. All studies were compared by genotype (CC versus CG+GG), based on functional studies.For the maternal genotype analysis, 1,165 PTBs and 3,830 term controls were evaluated. Populations were stratified into women of European descent (for whom the most data were available) and women of heterogeneous origin or admixed populations. All ancestry was self-reported. Women of European descent had a summary odds ratio (OR) of 0.68, (95% confidence interval (CI) 0.51 - 0.91), indicating that the CC genotype is protective against PTB. The result for non-European women was not statistically significant (OR 1.01, 95% CI 0.59 - 1.75). For the fetal genotype analysis, four studies were included; there was no significant association with PTB (OR 0.98, 95% CI 0.72 - 1.33). Sensitivity analysis showed that preterm premature rupture of membrane (PPROM) may be a confounding factor contributing to phenotype heterogeneity.IL6 SNP rs1800795 genotype CC is protective against PTB in women of European descent. It is not significant in other heterogeneous or admixed populations, or in fetal genotype analysis.Population structure is an important confounding factor that should be controlled for in studies of PTB.
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Project description:ImportanceEndometriosis is an inflammatory disease with a heterogeneous presentation that affects women of childbearing age. Given the limitations of previous retrospective studies, it is still unclear whether endometriosis has adverse implications for pregnancy outcomes.ObjectiveTo evaluate the association between the presence of endometriosis and preterm birth and whether the risk varied according to the disease phenotype.Design, setting, and participantsThis cohort study with exposed and unexposed groups was conducted in 7 maternity units in France from February 4, 2016, to June 28, 2018. Participants included women with singleton pregnancies who were followed up before 22 weeks' gestation along with their newborns delivered at or after 22 weeks' gestation. The final follow-up occurred in July 2019. Data were analyzed from October 7, 2020, to February 7, 2021.ExposuresWomen in the endometriosis group had a documented history of endometriosis and were classified according to 3 endometriosis phenotypes: isolated superficial peritoneal endometriosis (SUP), ovarian endometrioma (OMA; potentially associated with SUP), and deep endometriosis (DE; potentially associated with SUP and OMA). Women in the control group did not have a history of clinical symptoms of endometriosis before their current pregnancy.Main outcomes and measuresThe primary outcome was preterm birth between 22 weeks and 36 weeks 6 days of gestation. Association between endometriosis and the primary outcome was assessed through univariate and multivariate logistic regression analyses and was adjusted for the following risk factors associated with preterm birth: maternal age, body mass index (calculated as weight in kilograms divided by height in meters squared) before pregnancy, country of birth, parity, previous cesarean delivery, history of myomectomy and hysteroscopy, and preterm birth. The same analysis was performed according to the 3 endometriosis phenotypes (SUP, OMA, and DE).ResultsOf the 1351 study participants (mean [SD] age, 32.9 [5.0] years) who had a singleton delivery after 22 weeks of gestation, 470 were assigned to the endometriosis group (48 had SUP [10.2%], 83 had OMA [17.7%], and 339 had DE [72.1%]) and 881 were assigned to the control group. No difference was observed in the rate of preterm deliveries before 37 weeks 0 days of gestation between the endometriosis and control groups (34 of 470 [7.2%] vs 53 of 881 [6.0%]; P = .38). After adjusting for confounding factors, endometriosis was not associated with preterm birth before 37 weeks' gestation (adjusted odds ratio, 1.07; 95% CI, 0.64-1.77). The results were comparable for the different disease phenotypes (SUP: 6.2% [3 of 48]; OMA: 7.2% [6 of 83]; and DE: 7.4% [25 of 339]; P = .84).Conclusions and relevanceThis cohort study found no association between endometriosis and preterm birth, and the disease phenotype did not appear to alter the result. Monitoring the pregnancy beyond the normal protocols or changing management strategies for women with endometriosis may not be warranted to prevent preterm birth.
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