Table 1.
Demographic characteristics before and after propensity score matching.
| Before PSM | After PSM | |||||
|---|---|---|---|---|---|---|
| Characteristic | Study group | Control group | P value | Study group | Control group | P value |
| (n=314) | (n=2691) | (n=312) | (n=623) | |||
| Age (years) | 30.3 ± 4.0 | 30.2 ± 4.0 | 0.842 | 30.2 ± 3.9 | 30.4 ± 4.0 | 0.616 |
| Infertility type, n (%) | 0.654 | 0.418 | ||||
| primary | 178 (56.7) | 1561 (58.0) | 177 (56.7) | 336 (53.9) | ||
| secondary | 136 (43.3) | 1130 (42.0) | 135 (43.3) | 287 (46.1) | ||
| Duration of infertility, n (%) | 0.355 | 0.449 | ||||
| 1-2 | 92 (29.3) | 740 (27.5) | 92 (29.5) | 172 (27.6) | ||
| 3-5 | 185 (58.9) | 1555 (57.8) | 184 (59.0) | 361 (57.9) | ||
| ≥6 | 37 (11.8) | 396 (14.7) | 36 (11.5) | 90 (14.4) | ||
| Cause of infertility, n (%) | 0.265 | 0.869 | ||||
| female | 148 (47.1) | 1387 (51.5) | 146 (46.8) | 309 (49.6) | ||
| male | 23 (7.3) | 202 (7.5) | 23 (7.4) | 46 (7.4) | ||
| combined | 118 (37.6) | 949 (35.3) | 118 (37.8) | 222 (35.6) | ||
| unknown | 25 (8.0) | 153 (5.7) | 25 (8.0) | 46 (7.4) | ||
| BMI (kg/m2) | 21.2 ± 2.8 | 22.7 ± 3.4 | <0.001 | 21.3 ± 2.8 | 21.2 ± 2.8 | 0.930 |
| Basal FSH (mIU/mL) | 7.7 ± 2.2 | 7.5 ± 2.5 | 0.164 | 7.7 ± 2.2 | 7.7 ± 2.4 | 0.626 |
| Basal E2 (pg/ml) | 50.9 ± 23.8 | 46.0 ± 20.5 | <0.001 | 50.5 ± 23.2 | 51.2 ± 22.3 | 0.620 |
| AMH (ng/ml)* | 5.0 (3.0-7.9) | 5.6 (3.0-9.9) | 0.014 | 5.0 (3.1-7.9) | 5.1 (2.8-9.2) | 0.610 |
| Endometrial thickness (mm) | 9.9 ± 1.8 | 10.2 ± 1.9 | 0.004 | 9.9 ± 1.8 | 9.8 ± 1.8 | 0.497 |
| Embryo developmental stage, n (%) | 0.656 | 0.948 | ||||
| D3 | 100 (31.8) | 824 (30.6) | 100 (32.1) | 201 (32.3) | ||
| D5/D6 | 214 (68.2) | 1867 (69.4) | 212 (67.9) | 422 (67.7) | ||
| Number of transferred embryos | 1.8 ± 0.4 | 1.8 ± 0.5 | 0.825 | 1.8 ± 0.4 | 1.8 ± 0.5 | 0.264 |
| Number of good-quality embryos | 0.467 | 0.984 | ||||
| 0 | 103 (32.8) | 927 (34.4) | 103 (33.0) | 205 (32.9) | ||
| 1 | 137 (43.6) | 1078 (40.1) | 135 (43.3) | 273 (43.8) | ||
| 2 | 74 (23.6) | 686 (25.5) | 74 (23.7) | 145 (23.3) | ||
*Data are presented as the median (quartiles). Other data are presented as mean ± SD or n (%). PSM, propensity score matching; BMI, body mass index; FSH, follicle-stimulating hormone; E2, estradiol; AMH, anti-Müllerian hormone.