Variables | No. of PL/total (685/ 5485) | PL rate | HR (95% CI)a | P a |
---|---|---|---|---|
Maternal age | ||||
  < 30 | 292/2556 | 11.4% | 1.00[Reference] |  |
 30–35 | 283/2361 | 12.0% | 1.06(0.90–1.25) | 0.508 |
 36–40 | 84/472 | 17.8% | 1.63(1.28–2.08) | <0.001 * |
  > 40 | 20/53 | 37.7% | 4.14(2.63–6.52) | <0.001 * |
 Ptrend |  |  | 1.31(1.17–1.45) | <0.001 * |
Maternal BMI | ||||
  < 18.5 | 50/509 | 9.8% | 0.85(0.63–1.13) | 0.260 |
 18.5–25 | 487/4009 | 12.1% | 1.00[Reference] |  |
 25–28 | 97/641 | 15.1% | 1.24(1.00–1.55) | 0.051 |
  ≥ 28 | 42/235 | 17.9% | 1.52(1.11–2.10) | 0.010 * |
Paternal BMI | ||||
  < 18.5 | 9/103 | 8.7% | 0.67(0.33–1.35) | 0.264 |
 18.5–25 | 405/3309 | 12.2% | 1.00[Reference] |  |
 25–28 | 189/1344 | 14.1% | 1.15(0.96–1.37) | 0.120 |
  ≥ 28 | 69/603 | 12.3% | 0.95(0.74–1.23) | 0.691 |
Infertility type | ||||
 Primary | 337/2781 | 12.1% | 1.00[Reference] |  |
 Secondary | 319/2466 | 12.9% | 0.99(0.85–1.16) | 0.908 |
COH protocold | ||||
 GnRH-a long protocol | 391/3406 | 11.5% | 1.00[Reference] |  |
 GnRH-a short protocol | 186/1573 | 11.8% | 0.93(0.77–1.11) | 0.373 |
 GnRH antagonist protocol | 35/95 | 36.8% | 3.49(2.46–4.94) | <0.001 * |
 Minimal stimulation protocol | 44/186 | 23.7% | 1.83(1.31–2.54) | <0.001 * |
 GnRH-a rolonged protocol | 12/123 | 9.8% | 0.84(0.48–1.50) | 0.689 |
 Other protocol | 5/13 | 38.5% | 3.70(1.53–8.95) | 0.004 * |
The total Gn doseb | ||||
  < 1808.01 | 373/3181 | 11.7% | 1.00[Reference] |  |
  ≥ 1808.01 | 301/2208 | 13.6% | 1.12(0.96–1.30) | 0.161 |
Fertilization methods | ||||
 IVF | 579/4543 | 12.7% | 1.00[Reference] |  |
 ICSI | 98/875 | 11.2% | 0.87(0.70–1.08) | 0.205 |
Cycle type | ||||
 Fresh | 282/2675 | 10.5% | 1.00[Reference] |  |
 Frozen | 337/2477 | 13.6% | 1.30(1.11–1.53) | 0.001 * |
No. of embryos transferred | ||||
 1 | 82/474 | 17.3% | 1.00[Reference] |  |
 2 | 516/4324 | 11.9% | 0.71(0.56–0.90) | 0.005 * |
 3 | 84/637 | 13.2% | 0.67(0.49–0.91) | 0.010 * |
 Ptrend |  |  | 0.81(0.69–0.96) | 0.012 * |
Cleavage-stage embryo or blastocystd | ||||
 Cleavage-stage embryo | 466/3860 | 12.1% | 1.00[Reference] |  |
 Blastocyst | 198/1405 | 14.1% | 1.10(1.01–1.19) | 0.030 * |
Serum hCG levels 14Â days after transferc | ||||
  < 695.30 | 334/2205 | 15.1% | 1.00[Reference] |  |
  ≥ 695.30 | 115/1988 | 5.8% | 0.36(0.29–0.45) | <0.001 * |