| Included studies | Year | Nation | Simple size (Intervention /control) | Interventions Chewing gum start Chewing method | Control group | Outcome indicator | ||
| Liang [11] | 2007 | China | 60 | 60 | From delivery | Every 2 h 15 min each, 3 times/d | routine | ②③ |
| Abd-EI-Maeboud [12] | 2009 | Egypt | 93 | 107 | From 2 h postoperatively | 2 h/every times 15 min each, until first flatus | routine | ①②③ |
| Luo [13] | 2010 | China | 150 | 150 | From 2h postoperatively | 4 times/d, 10 - 15 min each Until 3 days after CD | routine | ①②③ |
| Wang [14] | 2011 | China | 116 | 117 | From 2 h postoperatively | Every 2 h, 0 - 15 min each until first flatus | routine | ①② |
| Ledari [15] | 2012 | Iran | 50 | 50 | From 6 h postoperatively | 3 times/d At least 1 h each Until discharge | routine | ①②③④ |
| Ledari [16] | 2013 | Iran | 30 | 30 | From 6 h postoperatively | 3 times/d At least 1 h each Until discharge | routine | ①②③④ |
| Rashad [17] | 2013 | Saudi Arabia | 30 | 30 | From posto-anesthesia | 3 times/d 30 min each Until discharge | routine | ①②③ |
| Ajuzieogu [18] | 2014 | Nigeria | 90 | 90 | From the first day postoperatively | 3 times/d 30 min each Until 5 days after CD | routine | ①②③ |
| Jian Tao [19] | 2015 | China | 40 | 40 | From 2 h postoperatively | Every 2 h, 15 min each Until first flatus | routine | ①②③ |
| Lang [20] | 2017 | China | 60 | 60 | From 2 h postoperatively | 3 times/d 30 min each Until first flatus | routine | ②③ |
| Feng [21] | 2017 | China | 130 | 130 | From 15 min postoperatively | Every 30 min 10 - 15 min each Until first flatus | routine | ①②③ |
| Wang [22] | 2018 | China | 110 | 110 | From 2 h postoperatively | 4 times/d 15 min each | routine | ①②③ |
| Magdy [23] | 2018 | Egypt | 100 | 100 | From 2 h postoperatively | Every 2 h, 10 min each Until first flatus | routine | ①②③ |