Table 1. Baseline characteristics.
| Cycle 1 (n = 188) | Cycle ≥ 2 (n = 286) | p-value | |
|---|---|---|---|
| Age (y.o.) | 33.74 ± 4.39 | 33.94 ± 4.39 | 0.629 t |
| Age > 35 y.o. at retrieval | 65 (34.57) | 103 (36.01) | 0.752 k |
| Smoker | 17 (9.04) | 29 (10.14) | 0.689 k |
| BMI | 23.65 ± 4.35 | 23.15 ± 4.00 | 0.237 t |
| BMI > 30 | 20 (10.64) | 20 (6.99) | 0.163 k |
| Type of infertility | 0.920 k | ||
| Primary | 131 (68.68) | 198 (69.23) | |
| Secondary | 57 (30.32) | 88 (30.77) | |
| Length of the infertility (y.o.) | 4.32 ± 2.46 | 4.54 ± 2.27 | 0.366 t |
| Cause of the infertility | 0.461 k | ||
| Ovulation disorder | 17 (9.04) | 30 (10.49) | |
| Male factor | 50 (26.60) | 76 (26.57) | |
| Tubal factor | 30 (15.96) | 27 (9.44) | |
| Endometriosis | 33 (17.55) | 47 (16.44) | |
| Idiopathic | 27 (14.36) | 48 (16.78) | |
| Diminished ovarian reserve | 2 (1.06) | 5 (1.75) | |
| More than one cause | 29 (15.43) | 53 (18.53) | |
| Numbers of previous IVF/ICSI attempts | 0.131 k | ||
| 1 | 106 (56.38) | 171 (59.79) | |
| 2 | 29 (15.43) | 56 (19.58) | |
| > 3 | 53 (28.19) | 59 (20.63) | |
| Ovarian reserve | |||
| FSH (U/L) | 6.29 ± 1.86 | 6.34 ± 1.68 | 0.747 t |
| FSH > 8 | 22 (11.70) | 36 (12.59) | 0.777 k |
| AMH (ng/mL) | 5.80 ± 4.19 | 5.58 ± 4.06 | 0.576 t |
| AMH < 2 | 25 (13.30) | 37 (12.94) | 0.920 k |
| AFC | 20.56 ± 10.65 | 21.20 ± 11.69 | 0.547 t |
| AFC < 10 | 23 (12.23) | 35 (12.24) | 0.999 k |
| Indications for FBT | 0.154 k | ||
| Risk of OHSS | 81 (43.09) | 128 (44.76) | |
| Elevated progesterone or inadequate endometrium | 11 (5.85) | 30 (10.49) | |
| Endometriosis | 36 (19.15) | 55 (19.23) | |
| Two or more ART failures | 47 (25.00) | 49 (17.13) | |
| Autoimmune disease and/or a high risk of thromboembolic disease | 13 (6.91) | 24 (8.39) |
y.o., years old; BMI, body mass index; IVF/ICSI, in vitro fertilization/ intra-cytoplasmic sperm injection; AFC, antral follicle count; AMH, anti-Müllerian hormone; FSH, follicle stimulating hormone; FBT, frozen blastocyst transfer; OHSS, ovarian hyperstimulation syndrome; ART, assisted reproductive technologies. Data are the mean ± standard error or n (%), unless specified otherwise.
t Student’s t-test
k Pearson’s chi-square test