Parameter | Full Cohort | P valuea | Singletons Only | P value | ||
---|---|---|---|---|---|---|
Frozen Transfers (n = 5513) | Fresh Transfers (n = 2589) | Frozen Transfers (n = 4071) | Fresh Transfers (n = 1889) | |||
Maternal age (years, mean (SD)) | 32.5 ± 3.7 | 32.3 ± 3.6 | 0.046 | 32.7 ± 3.8 | 32.5 ± 3.7 | 0.023 |
Gestational age (wk, mean (SD)) | 37.7 ± 2.2 | 37.8 ± 2.0 | 0.020 | 38.4 ± 1.7 | 38.5 ± 1.5 | 0.008 |
< 32 weeks (No.(%)) | 106(1.9) | 32(1.2) | 0.026 | 41(1.0) | 10(0.5) | 0.062 |
< 37 weeks (No.(%)) | 1124(20.4) | 458(17.7) | 0.004 | 314(7.7) | 105(5.6) | 0.002 |
Birth weight (g, mean (SD)) | 3142.0 ± 614.7 | 3106.3 ± 591.7 | 0.013 | 3353.5 ± 511.4 | 3329.6 ± 467.1 | 0.076 |
< 1500 g (No.(%)) | 95(1.7) | 32(1.2) | 0.098 | 32(0.8) | 7(0.4) | 0.064 |
< 2500 g (No.(%)) | 751(13.6) | 370(14.3) | 0.432 | 199(4.9) | 64(3.4) | 0.009 |
≥4000 g (No.(%)) | 316(5.7) | 129(5.0) | 0.163 | 316(7.8) | 129(6.8) | 0.202 |
Obstetrical events (No.(%)) | ||||||
 Cesarean section | 4336(78.7) | 1847(71.3) | < 0.001 | 2940(72.2) | 1178(62.4) | < 0.001 |
 Placenta previa | 374(6.8) | 184(7.1) | 0.592 | 251(6.2) | 117(6.2) | 0.966 |
 Hypertensive disorders | 775(14.1) | 242(9.3) | < 0.001 | 448(11.0) | 130(6.9) | < 0.001 |
 Gestational Diabetes | 1248(22.6) | 558(21.6) | 0.274 | 897(22.0) | 406(21.5) | 0.638 |