Table 1.
Demographic and clinical characteristics of all the participants (N = 6110).
| OS/FP quartile | P-value a | ||||
|---|---|---|---|---|---|
| Q1 (<0.57) | Q2 (0.57, 0.67) | Q3 (0.67, 0.77) | Q4 (≥0.77) | ||
| N | 1562 | 1832 | 1238 | 1478 | |
| Age (years) | 31.3 ± 3.9 | 31.5 ± 3.9 | 31.5 ± 3.9 | 31.7 ± 4.0 | 0.113 |
| ≤30, n (%) | 664 (42.5) | 739 (40.3) | 518 (41.8) | 599 (40.5) | |
| 30-35, n (%) | 666 (42.6) | 799 (43.6) | 517 (41.8) | 585 (39.6) | |
| >35, n (%) | 232 (14.9) | 294 (16.0) | 203 (16.4) | 294 (19.9) | |
| BMI (kg/m2) | 22.6 ± 3.2 | 22.7 ± 3.3 | 22.8 ± 3.5 | 22.7 ± 3.4 | 0.790 |
| BMI (kg/m2) categoryb | |||||
| Underweight (<18.5) | 113 (7.2) | 135 (7.4) | 95 (7.7) | 118 (8) | 0.423 |
| Normal (18.5–24.9) | 1092 (69.9) | 1247 (68.1) | 826 (66.7) | 973 (65.8) | |
| Overweight (25.0–29.9) | 291 (18.6) | 357 (19.5) | 256 (20.7) | 318 (21.5) | |
| Obese (≥30.0) | 41 (2.6) | 48 (2.6) | 43 (3.5) | 48 (3.2) | |
| AMH (ng/ml) | 4.1 ± 2.8 | 3.8 ± 2.6 | 3.9 ± 2.7 | 3.4 ± 2.2 | <0.001 |
| Gravidity | |||||
| 0 | 872 | 987 | 692 | 812 | 0.622 |
| 1+ | 690 | 845 | 546 | 666 | |
| Parity | |||||
| Nulliparous | 1464 | 1702 | 1143 | 1365 | 0.411 |
| 1+ | 98 | 130 | 95 | 113 | |
| Abortions | |||||
| 0 | 1079 | 1201 | 832 | 979 | 0.159 |
| 1+ | 483 | 631 | 406 | 499 | |
| Menstrual cycle length (days) | 30.5 ± 1.8 | 29 ± 2 | 28.9 ± 1.5 | 27.4 ± 1.9 | <0.001 |
| Usual menstrual bleeding (days) | 5.3 ± 1.4 | 5.2 ± 1.4 | 5.2 ± 1.4 | 5.1 ± 1.5 | 0.010 |
| Age at first menstruation (years) | 13.6 ± 1.2 | 13.6 ± 1.2 | 13.6 ± 1.2 | 13.6 ± 1.2 | 0.459 |
| Duration of infertility (years) | 3.7 ± 2.7 | 3.7 ± 2.7 | 3.8 ± 2.8 | 3.9 ± 2.8 | 0.104 |
| Bachelor or above | 613 (39.2) | 751 (41.0) | 486 (39.3) | 541 (36.6) | 0.084 |
| Current Smoker | 25 (1.6) | 28 (1.5) | 20 (1.6) | 22 (1.5) | 0.992 |
| Fertility status | |||||
| Primary infertility | 957 (61.3) | 1077 (58.8) | 752 (60.7) | 900 (60.9) | 0.444 |
| Secondary infertility | 605 (38.7) | 755 (41.2) | 486 (39.3) | 578 (39.1) | |
| Etiology of infertility | |||||
| Female factor | 765 (49) | 947 (51.7) | 635 (51.3) | 772 (52.2) | 0.421 |
| Male factor | 357 (22.9) | 388 (21.2) | 253 (20.4) | 278 (18.8) | |
| Mixed factors | 387 (24.8) | 438 (23.9) | 307 (24.8) | 374 (25.3) | |
| Idiopathic | 53 (3.4) | 59 (3.2) | 43 (3.5) | 54 (3.7) | |
| Type of ovarian stimulation | |||||
| Long GnRH-agonist | 601 (38.5) | 898 (49) | 723 (58.4) | 974 (65.9) | <0.001 |
| Short GnRH-agonist | 34 (2.2) | 91 (5) | 54 (4.4) | 64 (4.3) | |
| GnRH-antagonist | 927 (59.3) | 843 (46) | 461 (37.2) | 440 (29.8) | |
| Initial gonadotropin dose, IU | 225.2 ± 53.6 | 228.2 ± 54.2 | 230.6 ± 55.3 | 233.2 ± 56.8 | <0.001 |
| Total gonadotropin dose, IU | 1885.1 ± 602.1 | 2359.2 ± 827.5 | 2543.1 ± 764.5 | 2950.6 ± 879.7 | <0.001 |
| Endometrial thickness-HCG, mm | 10.4 ± 2.7 | 10.2 ± 2.8 | 10.1 ± 2.7 | 10.0 ± 2.9 | 0.001 |
| Duration of stimulation (days) | 8.3 ± 1.3 | 9.9 ± 2 | 10.6 ± 1.3 | 11.8 ± 2 | <0.001 |
| Insemination technique | |||||
| IVF | 963 (61.7) | 1162 (63.4) | 775 (62.6) | 931 (63) | 0.751 |
| ICSI | 599 (38.3) | 670 (36.6) | 463 (37.4) | 547 (37) | |
Values are n (%) for categorical variables and mean ± SD for continuous variables. SD, standard deviation; OS/FP, the ratio of duration of ovarian stimulation to follicular phase length; BMI, body mass index; AMH, anti-mullerian hormone; IVF, in vitro fertilization; ICSI, intracytoplasmic sperm injection.
Data on covariates were missing for BMI (n = 109), endometrial thickness-HCG (n = 99).
a
P values were calculated from nonparameter test (Kruskal-Wallis) or χ2 test.
b
BMI category (WHO classifification).