Table 1.
Patient baseline characteristics, cycle parameters, and neonatal outcomes by different groups of endometrial thickness on the hCG trigger day.
| Characteristics | 6.00–8.90 mm | 9.00–9.90 mm | 10.00–10.90 mm | >11.00 mm | P-value |
|---|---|---|---|---|---|
| (n = 378) | (n = 444) | (n = 541) | (n = 647) | ||
| Baseline characteristics | |||||
| Maternal age (year), mean ± SD | 31.50 ± 4.32 | 30.78 ± 3.90 | 30.64 ± 3.88 | 30.58 ± 3.91 | 0.015* |
| Paternal age (year), mean ± SD | 33.00 ± 5.01 | 32.52 ± 4.85 | 32.43 ± 4.73 | 32.09 ± 4.59 | 0.105 |
| Maternal BMI (kg/m2), mean ± SD | 22.22 ± 2.94 | 22.22 ± 3.10 | 22.07 ± 2.96 | 22.60 ± 3.42 | 0.103 |
| Basal FSH (IU/l), mean ± SD | 7.83 ± 2.46 | 7.91 ± 2.33 | 7.66 ± 2.51 | 7.35 ± 2.44 | <0.001* |
| AMH (ng/ml), mean ± SD | 2.85 ± 2.34 | 2.64 ± 2.06 | 2.81 ± 2.20 | 3.03 ± 2.34 | 0.035* |
| Type of infertility, n (%) | <0.001* | ||||
| Primary | 146 (38.62%) | 220 (49.55%) | 282 (52.13%) | 371 (57.34%) | |
| Secondary | 232 (61.38%) | 224 (50.45%) | 259 (47.87%) | 276 (42.66%) | |
| Infertility duration (year), mean ± SD | 3.61 ± 2.96 | 3.59 ± 2.71 | 3.77 ± 2.70 | 3.74 ± 2.57 | 0.660 |
| Infertility cause, n (%) | 0.234 | ||||
| Female | 259 (68.52%) | 292 (65.77%) | 360 (66.54%) | 393 (60.74%) | |
| Male | 68 (17.99%) | 88 (19.82%) | 93 (17.19%) | 148 (22.87%) | |
| Mixed | 33 (8.73%) | 38 (8.56%) | 57 (10.54%) | 61 (9.43%) | |
| Unexplained | 18 (4.76%) | 26 (5.86%) | 31 (5.73%) | 45 (6.96%) | |
| Prior gonadotropin cycle, mean ± SD | 1.24 ± 0.65 | 1.24 ± 0.57 | 1.23 ± 0.53 | 1.20 ± 0.50 | 0.536 |
| Cycle parameters | |||||
| Ovarian stimulation protocols, n (%) | 0.025* | ||||
| GnRH-a long protocol | 230 (60.85%) | 268 (60.36%) | 343 (63.40%) | 434 (67.08%) | |
| Antagonist protocol | 148 (39.15%) | 176 (39.64%) | 198 (36.60%) | 213 (32.92%) | |
| Dosage of gonadotropins (IU), mean ± SD | 2309.84 ± 1111.45 | 2375.34 ± 1086.39 | 2307.30 ± 1150.48 | 2202.80 ± 1109.18 | 0.017* |
| Stimulation duration (days), mean ± SD | 11.40 ± 2.35 | 11.54 ± 2.11 | 11.62 ± 2.18 | 11.66 ± 2.18 | 0.324 |
| E2 level on HCG day (pg/ml), mean ± SD | 2809.38 ± 1299.41 | 2969.08 ± 1255.00 | 3089.74 ± 1316.63 | 3051.18 ± 1215.43 | 0.006* |
| Number of oocytes retrieved, mean ± SD | 9.17 ± 3.87 | 9.72 ± 3.90 | 9.62 ± 3.95 | 9.95 ± 3.64 | 0.018* |
| Retrieved MII oocytes, mean ± SD | 7.97 ± 3.40 | 8.27 ± 3.57 | 8.28 ± 3.60 | 8.54 ± 3.32 | 0.089 |
| Fertilization method, n (%) | 0.023* | ||||
| IVF | 273 (72.22%) | 292 (65.77%) | 363 (67.10%) | 403 (62.29%) | |
| ICSI | 93 (24.60%) | 129 (29.05%) | 146 (26.99%) | 212 (32.77%) | |
| IVF + ICSI | 12 (3.17%) | 23 (5.18%) | 32 (5.91%) | 32 (4.95%) | |
| Fertilization rate (%), mean ± SD | 83.58 ± 15.56 | 81.84 ± 16.92 | 83.07 ± 16.55 | 83.58 ± 16.07 | 0.320 |
| Number of available embryos, mean ± SD | 4.27 ± 2.30 | 4.55 ± 2.47 | 4.42 ± 2.33 | 4.70 ± 2.33 | 0.071 |
| Stage embryo transferred, n (%) | 0.001* | ||||
| D3 | 332 (87.83%) | 376 (84.68%) | 455 (84.10%) | 510 (78.83%) | |
| D5 | 46 (12.17%) | 68 (15.32%) | 86 (15.90%) | 137 (21.17%) | |
| Number of embryos transferred, n (%) | 0.188 | ||||
| 1 | 95 (25.13%) | 116 (26.13%) | 139 (25.69%) | 200 (30.91%) | |
| 2 | 282 (74.60%) | 328 (73.87%) | 401 (74.12%) | 444 (68.62%) | |
| 3 | 1 (0.26%) | 0 (0.00%) | 1 (0.18%) | 3 (0.46%) | |
| Endometrial thickness (mm), mean ± SD | 7.84 ± 0.68 | 9.11 ± 0.23 | 10.08 ± 0.20 | 11.70 ± 0.90 | <0.001* |
| Endometrial type, n (%) | 0.296 | ||||
| A | 7 (1.85%) | 11 (2.48%) | 7 (1.29%) | 5 (0.77%) | |
| A-B | 20 (5.29%) | 24 (5.41%) | 34 (6.28%) | 29 (4.48%) | |
| B | 120 (31.75%) | 142 (31.98%) | 154 (28.47%) | 204 (31.53%) | |
| B-C | 205 (54.23%) | 234 (52.70%) | 316 (58.41%) | 354 (54.71%) | |
| C | 26 (6.88%) | 33 (7.43%) | 30 (5.55%) | 55 (8.50%) | |
| Neonatal outcomes indicators | |||||
| Gender of newborn, n (%) | 0.507 | ||||
| Male | 203 (53.70%) | 215 (48.42%) | 277 (51.20%) | 327 (50.54%) | |
| Female | 175 (46.30%) | 229 (51.58%) | 264 (48.80%) | 320 (49.46%) | |
| Newborn height (cm), mean ± SD | 50.22 ± 2.23 | 50.22 ± 1.99 | 50.14 ± 1.98 | 50.19 ± 2.29 | 0.681 |
| GA (week), mean ± SD | 38.74 ± 2.00 | 38.96 ± 1.68 | 39.06 ± 1.52 | 39.08 ± 1.73 | 0.013* |
| Birthweight (g), mean ± SD | 3123.48 ± 491.04 | 3201.79 ± 556.65 | 3191.90 ± 446.38 | 3276.62 ± 495.47 | 0.025* |
| Z-score, mean ± SD | 0.05 ± 1.15 | 0.07 ± 1.13 | −0.05 ± 1.00 | 0.19 ± 1.02 | 0.220 |
| Birthweight, n (%) | 0.031* | ||||
| Normal birthweight | 342 (90.48%) | 373 (84.01%) | 494 (91.31%) | 574 (88.72%) | |
| Very low birth weight (<1500 g) | 6 (1.59%) | 5 (1.13%) | 0 (0.00%) | 6 (0.93%) | |
| Low birthweight (<2500 g) | 26 (6.88%) | 44 (9.91%) | 16 (2.96%) | 23 (3.55%) | |
| Fetal macrosomia (≥4000 g) | 4 (1.05%) | 22 (4.95%) | 31 (5.73%) | 44 (6.80%) | |
| Gestational age, n (%) | 0.023* | ||||
| Full-term (≥37 weeks) | 319 (84.39%) | 400 (90.09%) | 500 (92.42%) | 614 (94.90%) | |
| Preterm (32–36 weeks) | 48 (12.70%) | 39 (8.78%) | 41 (7.58%) | 24 (3.71%) | |
| Very preterm (<32 weeks) | 11 (2.91%) | 5 (1.13%) | 0 (0.00%) | 9 (1.39%) | |
| Small for gestational age, n (%) | 26 (6.88%) | 37 (8.33%) | 43 (7.95%) | 43 (6.65%) | 0.686 |
| Very small for gestational age, n (%) | 5 (1.32%) | 11 (2.48%) | 14 (2.59%) | 10 (1.55%) | 0.384 |
| Large for gestational age, n (%) | 40 (10.58%) | 39 (8.78%) | 53 (9.80%) | 51 (7.88%) | 0.469 |
| Very large for gestational age, n (%) | 16 (4.23%) | 13 (2.93%) | 19 (3.51%) | 24 (3.71%) | 0.789 |
| Mode of delivery, n (%) | 0.155 | ||||
| Vaginal | 121 (32.01%) | 154 (34.68%) | 183 (33.83%) | 249 (38.49%) | |
| Caesarean section | 257 (67.99%) | 290 (65.32%) | 358 (66.17%) | 398 (61.51%) | |
AMH: anti-Müllerian hormone; E2: estrogen; GA: gestational age; GnRH-a: GNRH agonist.
*
Statistically significant, with P < 0.05.