Table 2. ART characteristics and outcomes.
| Cycle 1 (n = 188) | Cycle ≥ 2 (n = 286) | p-value | |
|---|---|---|---|
| Stimulation protocol | 0.771k | ||
| GnRH antagonist | 177 (94.16) | 265 (92.66) | |
| Long GnRH agonist | 8 (4.27) | 14 (4.89) | |
| Short agonist | 3 (1.57) | 7 (2.45) | |
| Duration of the stimulation (days) | 9.19 ± 1.37 | 9.41 ± 1.26 | 0.087 t |
| Total dose of injected gonadotropins (IU) | 1,963.91±707.48 | 2,077.84±784.64 | 0.102 t |
| Type of triggering | 0.033 k | ||
| hCG | 25 (13.30) | 60 (20.98) | |
| GnRH agonist | 163 (86.70) | 226 (79.02) | |
| Peak estradiol levels (pg/mL)a | 2,707.97±1481.29 | 2,839.61±1631.70 | 0.365 t |
| Peak progesterone levels (ng/mL)a | 0.85 ± 0.48 | 0.95 ± 0.73 | 0.101 t |
| Number of oocytes retrieved | 15.85 ± 7.55 | 15.38 ± 6.87 | 0.494 t |
| Route of estradiol for endometrial preparation | 0.060 k | ||
| Transdermal | 175 (93.08) | 251 (87.76) | |
| Oral | 13 (6.92) | 35 (12.24) | |
| Endometrial thickness ≥ 10 mm | 61 (32.45) | 70 (24.48) | 0.057 k |
| Progesterone before transfer (ng/mL) | 0.40 ± 0.25 | 0.43 ± 0.25 | 0.230 t |
| Number of embryos transferred | 0.574 k | ||
| 1 | 185 (98.40) | 282 (98.60) | |
| 2 | 3 (1.60) | 4 (1.40) | |
| Good quality embryo transfer b | 165/188 (87.77) | 258/286 (90.21) | 0.399 k |
| Clinical pregnancy rate | 82/188 (43.62) | 125/286 (43.71) | 0.999 k |
| Miscarriage rate | 20/82 (24.39) | 37/125 (29.60) | 0.413 k |
| Ongoing pregnancy rate | 62/188 (32.98) | 88/286 (30.77) | 0.610 k |
| Live birth rate | 59/188 (31.38) | 85/286 (29.72) | 0.696 k |
| Gestational age at delivery ‡, WGA | 39.56 ± 2.00 | 39.33 ± 2.47 | 0.564 t |
| Number of twin pregnancies | 0/59 (0.00) | 3/85 (3.43) | 0.203 k |
| Term birth < 37 GA‡ | 4/59 (6.78) | 7/85 (8.24) | 0.505 k |
| Mean birth weight ‡, g | 3,436.55 ± 508.05 | 3,234.23 ± 606.30 | 0.045 t |
| Birth weight ≥ 4,000 g ‡ | 0/59 | 0/82 | 1.000 |
| Birth weight < 2,500 g ‡ | 2/59 (3.39) | 6/82 (7.32) | 0.271 k |
| Z-score ‡ | 0.14 ± 0.94 | -0.21 ± 1.13 | 0.107 t |
IVF/ICSI, in vitro fertilization/ intra-cytoplasmic sperm injection; WGA, weeks of gestational age; ART, assisted reproductive technology
a On the day of triggering
b A good-quality embryo was defined as a B3-B4 or B5 embryo ≥ BB (AA, AB, BA, BB) according to the grading scale proposed by Gardner
t Student’s t-test
k Pearson’s chi-square test
‡ Among singletons
Data are the mean ± standard error or n (%), unless specified otherwise