Table 1.
Basal demographic and cycle features of FETs which proceeded either within the immediate cycle following OPU (Immediate FET group) or subsequently (Delayed FET group) after a failed-fresh ET. Data are presented as numbers (%) unless otherwise noted
| Characteristic | Immediate FET group | Delayed FET group | P-value |
|---|---|---|---|
| Randomized subjects | 366 | 366 | |
| Female age at oocyte retrieval (years; mean (SD)) | 33.8 (3.2) | 33.3 (4.1) | 0.062 |
| Etiology of infertility | 0.815 | ||
| Tubal factor | 184 (50.3) | 177 (48.4) | |
| Anovulation | 43 (11.7) | 36 (9.8) | |
| Male factor | 59 (16.1) | 63 (17.2) | |
| Combined factor | 68 (18.6) | 75 (20.5) | |
| Unexplained sterility | 12 (3.3) | 15 (4.1) | |
| FET interval (days; mean (SD)) | 25.2 (5.4) | 103.5 (23.3) | < 0.001 |
| Duration of infertility (years; median (IQR)) | 4 (4) | 5 (2) | 0.817 |
| Nulliparous | 176 (48.1) | 180 (49.2) | 0.767 |
| Gravidity (median (IQR)) | 1 (2) | 1 (2) | 0.978 |
| Parity (median (IQR)) | 0 (1) | 0 (1) | 0.844 |
| BMI (kg/m2; mean (SD)) | 23.1 (2.9) | 23.5 (2.9) | 0.116 |
| AMH (ng/ml; median (IQR)) | 2.9 (1.6) | 3.1 (1.2) | 0.354 |
| Basic FSH (mIU/ml; mean (SD)) | 6.7 (1.0) | 6.8 (1.9) | 0.920 |
| Basic LH (mIU/ml; mean (SD)) | 5.0 (1.5) | 5.0 (1.2) | 0.688 |
| Basic estradiol (pg/ml; median (IQR)) | 35.4 (7.0) | 35.3 (8.4) | 0.755 |
| Total AFC (mean (SD)) | 10.4 (3.2) | 10.7 (2.9) | 0.329 |
| No of days of COS (mean (SD)) | 10.7 (2.1) | 10.9 (1.8) | 0.132 |
| Total Gn dose administered (IU; mean (SD)) | 2140.5 (469.3) | 2180.5 (551.2) | 0.291 |
| Method of fertilization | 0.875 | ||
| IVF | 247 (67.5) | 245 (66.9) | |
| ICSI | 119 (32.5) | 121 (33.1) | |
| No of oocytes retrieved (mean (SD)) | 10.5 (2.1) | 10.7 (2.8) | 0.170 |
| No of embryos available for transfer (median (IQR)) | 5.5 (2) | 5 (5) | 0.235 |
| No of high-quality day 3 embryos (median (IQR)) | 2 (0) | 2 (2) | 0.315 |
| No of embryos transferred in fresh ET cycle (median (IQR)) | 2 (0) | 2 (0) | 0.697 |
| Single embryo transfer | 31 (8.5) | 34 (9.3) | |
| Double embryo transfer | 335 (91.5) | 332 (90.7) | |
| No of frozen thawed embryos transferred (median (IQR)) | 2 (0) | 2 (0) | 0.956 |
| Single embryo transfer | 32 (9.8) | 31 (9.7) | |
| Double embryo transfer | 294 (90.2) | 289 (90.3) | |
| Endometrial thickness prior to FET (mm; mean (SD)) | 10.5 (1.8) | 10.3 (1.9) | 0.388 |
| Moderate/severe depression prior to FET (MDI) a | 20/326 (6.1) | 34/320 (10.6) | 0.039 |
| High stress level prior to FET (PSS) b | 73/326 (22.4) | 97/320 (30.3) | 0.022 |
Abbreviation: FET Frozen embryo transfer, IQR Interquartile range, OPU Ovum pick-up, Interval Days elapsed from oocyte retrieval to frozen embryo transfer, BMI Body mass index, AMH Anti-müllerian hormone, FSH Follicle stimulating hormone, LH Luteinizing hormone, AFC Antral follicle count, COS Controlled ovarian stimulation, IVF In-vitro fertilization, ICSI Intracytoplasmic sperm injection, Gn Gonadotropin, IU International units, MDI Major Depression Index, PSS Cohen’s Perceived Stress Scale
a Moderate depression (two core symptoms and four or more additional symptoms); Severe depression (three core symptoms and five or more additional symptoms)
b High stress level defined as ≥ 19 on the PSS scale