Table 2. Descriptive statistics of categorical variables for clinical pregnancy and non-clinical pregnancy groups.
| N = 17,288 | Pregnancy (N = 6,548) |
No pregnancy | p-value | ||
|---|---|---|---|---|---|
| (N = 10,740) | |||||
| N | Percentage | N | Percentage | ||
| Female age group | *** | ||||
| <30 years | 294 | 4.49 | 267 | 2.49 | |
| 30~34 years | 1903 | 29.06 | 2091 | 19.47 | |
| 35~39 years | 3124 | 47.71 | 4425 | 41.20 | |
| >40 years | 1227 | 18.74 | 3957 | 36.84 | |
| Cause of infertility | *** | ||||
| Tubal factor | 902 | 13.78 | 1335 | 12.43 | |
| Ovary factor | 607 | 9.27 | 826 | 7.69 | |
| Endometriosis | 691 | 10.55 | 1037 | 9.66 | |
| Uterine factor (myoma adenomyosis, uterine synechia) | 306 | 4.67 | 454 | 4.23 | |
| Others (other female factors) | 2078 | 31.73 | 3962 | 36.89 | |
| Male factor | 985 | 15.04 | 1311 | 12.21 | |
| Either two factors | 940 | 14.36 | 1779 | 16.56 | |
| Unexplained | 39 | 0.60 | 36 | 0.34 | |
| Oocyte retrieval | ** | ||||
| Yes | 4416 | 67.44 | 7412 | 69.01 | |
| No | 2132 | 32.56 | 3328 | 30.99 | |
| Artificially assisted reproductive method | |||||
| IVF/ET | 6544 | 99.94 | 10,739 | 99.99 | |
| ZIFT/TET | 4 | 0.06 | 1 | 0.01 | |
| Fertilization method | *** | ||||
| ICSI | 4375 | 66.81 | 7352 | 68.45 | |
| Assisted hatching | 223 | 3.41 | 226 | 2.10 | |
| ICSI and assisted hatching | 13 | 0.20 | 27 | 0.25 | |
| PGS | 121 | 1.85 | 117 | 1.09 | |
| PGD | 0 | 0.00 | 0 | 0.00 | |
| No Use | 1760 | 26.88 | 2943 | 27.40 | |
| Others | 56 | 0.86 | 75 | 0.70 | |
| Source of sperm and oocytes | |||||
| Without donation | 6445 | 98.43 | 10,596 | 98.66 | |
| Oocyte donation | 75 | 1.15 | 93 | 0.87 | |
| Sperm donation | 28 | 0.43 | 51 | 0.47 | |
| The use of fresh/freeze-thaw | ** | ||||
| Fresh | 4406 | 67.29 | 7456 | 69.42 | |
| Frozen | 2142 | 32.71 | 3284 | 30.58 | |
| Ovarian hyperstimulation syndrome | *** | ||||
| None | 6323 | 96.56 | 10,526 | 98.01 | |
| Mild | 218 | 3.33 | 212 | 1.97 | |
| Moderate | 6 | 0.09 | 1 | 0.01 | |
| Severe | 1 | 0.02 | 1 | 0.01 | |
| Ovarian stimulation protocol | *** | ||||
| Natural cycle (including frozen-embryo transfer cycle) | 2132 | 55.84 | 3328 | 54.51 | |
| Oral stimulation drug | 0 | 0.00 | 3 | 0.05 | |
| Short protocol | 248 | 6.50 | 442 | 7.24 | |
| Long protocol | 306 | 8.01 | 356 | 5.83 | |
| Ultra-long protocol | 124 | 3.25 | 165 | 2.70 | |
| Antagonist protocol | 1006 | 26.35 | 1803 | 29.53 | |
| Others | 2 | 0.05 | 8 | 0.13 | |
* p < 0.05,
** p < 0.01,
*** p < 0.001 by a chi-squared test for categorical variables.
IVF/ET, in vitro fertilization/embryo transfer; ZIFT/TET, zygote intrafallopian transfer/tubal embryo transfer; ICSI, intracytoplasmic sperm injection; PGS, preimplantation genetic screening; PGD, preimplantation genetic diagnosis.