| Table 2. Association between the type of pregnancy and the outcome of each article | |||||
| Outcome | Pregnancy rate n (%) | Total | x2 | p* | |
| Artificial | Natural | ||||
| Chang et al., 2011 | |||||
| Negative | 119 (58.3) | 180 (58.1) | 299 (58.2) | 0.04 | 0.95 |
| Positive | 85 (41.7) | 130 (41.9) | 215 (41.8) | ||
| Total | 204 | 310 | 514 | ||
| Morozov et al., 2007 | |||||
| Negative | 133 (76.4) | 43 (63.2) | 176 (72.7) | 4.29 | 0.03 |
| Positive | 41 (23.6) | 25 (36.8) | 66 (27.3) | ||
| Total | 174 | 68 | 242 | ||
| Tomás et al., 2012 | |||||
| Negative | 2167 (75.8) | 920 (78.8) | 3087 (76.7) | 4.02 | 0.05 |
| Positive | 691 (24.2) | 248 (21.2) | 939 (23.3) | ||
| Total | 2858 | 1168 | 4026 | ||
| Xiao et al., 2012 | |||||
| Negative | 418 (64.7) | 236 (62.1) | 654 (63.7) | 0.70 | 0.40 |
| Positive | 228 (35.3) | 144 (37.9) | 372 (36.3) | ||
| Total | 646 | 380 | 1026 | ||
| Zheng et al., 2015 | |||||
| Negative | 1037 (41.4) | 331 (50.6) | 1368 (43.3) | 18.00 | <0.001 |
| Positive | 1469 (58.6) | 323 (49.4) | 1792 (56.7) | ||
| Total | 2506 | 654 | 3160 | ||
| *Pearson's Chi-squared | |||||