Table 1 Baseline characteristics of the matched groups and the pregnancy type subgroup
Characteristics | WR group | NonEP group | P | Singleton subgroup | Twin subgroup | P |
|---|---|---|---|---|---|---|
n | 75 | 375 | 50 | 11 | ||
Age (years) | 36(33,40) | 36(32,40) | 0.467 | 36(33,39) | 36(33,37) | 0.785 |
BMI (kg/m2) | 22.99(20.20,25.40) | 22.43(20.43,24.52) | 0.282 | 23.06(20.41,25.45) | 21.70(19.95,23.53) | 0.404 |
Year of treatment (%) | 0.914 | 0.700 | ||||
2014–2015 | 28.0(21/75) | 29.9(112/375) | 28.0(14/50) | 18.2(2/11) | ||
2016–2017 | 34.7(26/75) | 35.2(132/375) | 34.0(17/50) | 27.3(3/11) | ||
2018–2019 | 37.3(28/75) | 34.9(131/375) | 38.0(19/50) | 54.5(6/11) | ||
Infertility duration (years) | 2(1,3) | 2(0,3) | 0.567 | 2(0,3) | 2(0,4) | 1.000 |
Gravidity | 0.879 | 1.000 | ||||
0 | 8.0(6/75) | 8.5(32/375) | 10.0(5/50) | 9.1(1/11) | ||
≥ 1 | 92.0(69/75) | 91.5(343/375) | 90.0(45/50) | 90.9(10/11) | ||
Parity | 0.592 | 1.000 | ||||
0 | 78.7(59/75) | 81.3(305/375) | 80.0(40/50) | 81.8(9/11) | ||
≥ 1 | 21.3(16/75) | 18.7(70/375) | 20.0(10/50) | 18.2(2/11) | ||
Tubal infertility (%) | 98.7(74/75) | 98.1(368/375) | 1.000 | 98.0(49/50) | 100(11/11) | 1.000 |
PCOS (%) | 6.7(5/75) | 5.9(22/375) | 0.790 | 6.0(3/50) | 18.2(2/11) | 0.218 |
Endometriosis (%) | 5.3(4/75) | 6.4(24/375) | 1.000 | 4.0(2/50) | 18.2(2/11) | 0.146 |
Male factor infertility (%) | 10.7(8/75) | 10.9(41/375) | 0.946 | 12.0(6/50) | 9.1(1/11) | 1.000 |
Endometrial preparation (%) | 0.625 | 0.629 | ||||
Natural cycles | 24.0(18/75) | 29.1(109/375) | 22.0(11/50) | 9.1(1/11) | ||
HRT cycles | 37.3(28/75) | 36.8(138/375) | 36.0(18/50) | 36.4(4/11) | ||
Stimulated cycles | 38.7(29/75) | 34.1(128/375) | 42.0(21/50) | 54.5(6/11) | ||
Endometrial thickness (mm) | 0.752 | 0.233 | ||||
< 8 | 9.3(7/75) | 7.2(27/375) | 8.0(4/50) | 0(0/0) | ||
8–11 | 61.3(46/75) | 65.1(244/375) | 66.0(33/50) | 45.5(5/11) | ||
> 11 | 29.3(22/75) | 27.7(104/375) | 26.0(13/50) | 54.5(6/11) | ||
No. of embryos transferred | 0.286 | 0.018 | ||||
1 | 48.0(36/75) | 41.3(155/375) | 60.0(30/50) | 18.2(2/11) | ||
2 | 52.0(39/75) | 58.7(220/375) | 40.0(20/50) | 81.8(9/11) | ||
Stage of embryo | 0.190 | 0.224 | ||||
Cleavage stage | 82.5(94/114) | 87.1(518/595) | 65.7(46/70) | 80.0(16/20) | ||
Blastocyst | 17.5(20/114) | 12.9(77/595) | 34.3(24/70) | 20.0(4/20) |