Table 1 The detailed information for the included articles.
Number | Study | Country | Sample | Sampling time | Deliver gestational week | Inflammatory factors | Function | Significance | Sample size (PTB/Term) |
|---|---|---|---|---|---|---|---|---|---|
1 | Ran, Y. (2021). | China | Maternal blood | 37 weeks | 37 weeks | IL-27p28 | Immune modulator | Significantly higher in PTB | 15/23 |
2 | Shafiq, M. (2021). | India | Maternal plasma | 28-30 weeks | Before 37 weeks | IL-1β | Pro-inflammatory mediator | Significantly higher in PTB | 25/193 |
| Â | IL-17A | Stimulating an inflammatory response | Significantly higher in PTB | ||||||
3 | Brien, M. E. (2020). | Spain | Maternal plasma | 26-29 weeks | Before 37 weeks | CXCL9 | Inflammatory activation | Significantly higher in PTB | 50/50 |
4 | McDonald, C. R. (2019). | Canada | Maternal plasma | 16 weeks | Before 37 weeks | IL-6 | Pro-inflammatory mediator | Significantly higher in PTB | 55/178 |
| Â | sTNFR2 | Inflammatory activation | Significantly higher in PTB | ||||||
5 | Escobar-Arregoces, F. (2018). | Colombia | Maternal blood | 25-33 weeks | Before 37 weeks | IFN-γ | Immune regulation | No significance | 23/23 |
|  | TNFα | Inflammatory activation | Significantly higher in PTB | ||||||
| Â | IL-10 | Pro-inflammatory mediator | Significantly higher in PTB | ||||||
| Â | IL-6 | Pro-inflammatory mediator | No significance | ||||||
| Â | IL-4 | Pro-inflammatory mediator | No significance | ||||||
| Â | IL-2 | Pro-inflammatory mediator | Significantly higher in PTB | ||||||
6 | Zhu, H. (2018). | China | Maternal plasma | 27-34 weeks | Before 37 weeks | IL-6 | Pro-inflammatory mediator | Significantly higher in PTB | 7/20 |
|  | IL-1β | Pro-inflammatory mediator | Significantly higher in PTB | ||||||
| Â | CRP | Inflammatory activation | Significantly higher in PTB | ||||||
7 | Shivakoti, R. (2018). | India | Maternal plasma | 21-33 weeks | 32-37 weeks | sCD163 | Macrophage activation | Significantly higher in PTB | 26/81 |
| Â | Â | Â | Â | Â | Â | I-FABP | Inflammatory activation | Significantly higher in PTB | Â |
8 | Wallenstein, M. B. (2016). | USA | Maternal serum | 25-33 weeks | Before 37 weeks | sTNFR1 | Inflammatory activation | Significantly higher in PTB | 34/34 |
| Â | Â | Â | Â | Â | Â | sTNFR2 | Inflammatory activation | Significantly higher in PTB | Â |
|  |  |  |  |  |  | TNFα | Inflammatory activation | Significantly higher in PTB |  |
|  |  |  |  |  |  | TNFβ | Inflammatory activation | Significantly higher in PTB |  |
| Â | Â | Â | Â | Â | Â | NGF | Inflammatory activation | Significantly higher in PTB | Â |
9 | López, M. (2016). | Spain | Maternal serum | Before 37 weeks | Before 37 weeks | sCD14 | Macrophage activation | Significantly higher in PTB | 9/27 |
10 | Mesa, F. (2016). | Spain | Maternal plasma | 33-37 weeks | 33-37 weeks | IL-1β | Pro-inflammatory mediator | Significantly higher in PTB | 54/53 |
| Â | Â | Â | Â | Â | Â | IL-6 | Pro-inflammatory mediator | Significantly higher in PTB | Â |
| Â | Â | Â | Â | Â | Â | IL-8 | Pro-inflammatory mediator | Significantly higher in PTB | Â |
| Â | Â | Â | Â | Â | Â | IL-10 | Pro-inflammatory mediator | Significantly higher in PTB | Â |
11 | Perunovic, N. (2016). | Serbia | Maternal serum | Before 37 weeks | Before 37 weeks | IL-1β | Pro-inflammatory mediator | No significance | 52/52 |
| Â | Â | Â | Â | Â | Â | IL-6 | Pro-inflammatory mediator | No significance | Â |
|  |  |  |  |  |  | TNFα | Inflammatory activation | No significance |  |
12 | Hastie, C. E. (2011). | UK | Maternal serum | 24-37 weeks | 24-37 weeks | CRP | Inflammatory activation | Significantly higher in PTB | 21/27 |
13 | Sorokin, Y. (2010). | USA | Maternal serum | 24-32 weeks | Before 37 weeks | IL-6 | Pro-inflammatory mediator | Significantly higher in PTB | 22/25 |
| Â | Â | Â | Â | Â | Â | CRP | Inflammatory activation | Significantly higher in PTB | Â |
14 | Torbé, A. (2007). | Poland | Maternal serum | 24-36 weeks | 31-37 weeks | IL-1β | Pro-inflammatory mediator | Significantly higher in PTB | 18/29 |
| Â | Â | Â | Â | Â | Â | IL-6 | Pro-inflammatory mediator | Significantly higher in PTB | Â |
15 | Skrablin, S. (2007). | Croatia | Maternal plasma | 27-34 weeks | 27-34 weeks | IL-6 | Pro-inflammatory mediator | Significantly higher in PTB | 20/20 |
|  |  |  |  |  |  | IL-1β | Pro-inflammatory mediator | Significantly higher in PTB |  |
| Â | Â | Â | Â | Â | Â | CRP | Inflammatory activation | Significantly higher in PTB | Â |
16 | Catov, J. M. (2007). | USA | Maternal serum | <21 weeks | 34-37 weeks | CRP | Inflammatory activation | Significantly higher in PTB | 20/20 |
17 | Goldenberg, R. L. (1996). | USA | Maternal plasma | 26 weeks | Before 37 weeks | Ferritin | Induce inflammation | Significantly higher in PTB | 51/485 |