Characteristics | Underweight (< 18.5 kg/m2) | Normal weight (18.5–22.9 kg/m2) | Overweight (23–27.4 kg/m2) | Obese (≥ 27.5 kg/m2) | P valuea | P valueb | P valuec |
---|---|---|---|---|---|---|---|
Patients, n | 2527 | 13,224 | 5079 | 1213 | Â | ||
Age (years) | 30.56 ± 3.61 | 31.36 ± 3.73 | 31.66 ± 3.79 | 31.11 ± 3.79 | < 0.001 | < 0.001 | 0.023 |
BMI (kg/m2) | 17.66 ± 0.73 | 20.67 ± 1.21 | 24.68 ± 1.22 | 29.89 ± 2.39 | < 0.001 | < 0.001 | < 0.001 |
Infertility duration (years) | 3.19 ± 2.37 | 3.36 ± 2.75 | 3.68 ± 2.90 | 4.10 ± 2.97 | 0.004 | < 0.001 | < 0.001 |
Gravidity | < 0.001 | 0.121 | 0.448 | ||||
 0 | 1577(62.4) | 7393(55.9) | 2756(54.3) | 672(55.4) |  | ||
 1 | 556(22.0) | 3042(23.0) | 1199(23.6) | 297(24.5) | |||
 ≥ 2 | 394(15.6) | 2789(21.1) | 1124(22.1) | 244(20.1) | |||
Parity | < 0.001 | 0.002 | 0.520 | ||||
 0 | 2418(95.7) | 12,220(92.4) | 4614(90.8) | 1120(92.3) |  | ||
 1 | 105(4.2) | 938(7.1) | 429(8.5) | 84(6.9) | |||
 ≥ 2 | 4(0.2) | 66(0.5) | 36(0.7) | 9(0.7) | |||
Main cause of infertility | 0.007 | < 0.001 | < 0.001 | ||||
 Tubal factor | 1341(53.1) | 7198(54.4) | 2666(52.5) | 553(45.6) |  | ||
 PCOS | 162(6.4) | 1077(8.1) | 796(15.7) | 346(28.5) | |||
 Diminish ovarian reserve | 183(7.2) | 875(6.6) | 278(5.5) | 41(3.4) | |||
 Endometriosis | 261(10.3) | 1179(8.9) | 307(6.0) | 44(3.6) | |||
 Uterine factor | 75(3.0) | 426(3.2) | 175(3.4) | 26(2.1) | |||
 Unexplained | 94(3.7) | 424(3.2) | 136(2.7) | 46(3.8) | |||
 Male factor | 411(16.3) | 2045(15.5) | 721(14.2) | 157(13.9) | |||
Number of OPU prior to FET | 0.043 | < 0.001 | < 0.001 | ||||
 1 | 1962(77.6) | 10,028(75.8) | 3689(72.6) | 824(67.9) |  | ||
 2 | 338(13.4) | 2026(15.3) | 895(17.6) | 241(19.9) | |||
 ≥ 3 | 227(9.0) | 1170(8.8) | 495(9.7) | 148(12.2) | |||
Fertilization method | 0.744 | 0.789 | 0.584 | ||||
 IVF | 1605(63.5) | 8470(64.1) | 3252(64.0) | 795(65.5) |  | ||
 ICSI | 601(23.8) | 3145(23.8) | 1225(24.1) | 277(22.8) | |||
 IVF+ ICSI | 321(12.7) | 1609(12.2) | 602(11.9) | 141(11.6) | |||
Year of treatment | 0.659 | < 0.001 | 0.037 | ||||
 2010–2012 | 550(21.8) | 2836(21.4) | 932(18.4) | 222(18.3) |  | ||
 2013–2014 | 881(34.9) | 4736(35.8) | 1809(35.6) | 453(37.3) | |||
 2015–2017 | 1096(43.4) | 5652(42.7) | 2338(46.0) | 538(44.4) |