From: Risk factors for twin pregnancy in women undergoing double cleavage embryo transfer
variables | Twins (n = 1511) | Singleton (n = 4778) | No delivery (n = 9170) | P valuea |
---|---|---|---|---|
Female age y | 29.4 ± 3.2 | 30.2 ± 3.7 | 30.7 ± 4.3 | < 0.001 |
  >35 | 41 (3%) | 391 (8%) | 1224 (13%) |  |
  ≤35 | 1470 (97%) | 4387 (92%) | 7946 (87%) |  |
Male age y | 31.7 ± 4.3 | 32.1 ± 4.6 | 32.9 ± 5.3 | < 0.001 |
  >35 | 244 (16%) | 991 (21%) | 2424 (26%) |  |
  ≤35 | 1265 (84%) | 3786 (79%) | 6737 (74%) |  |
Female BMI kg/m2 | 21.8 ± 2.7 | 21.9 ± 2.8 | 22.1 ± 2.9 | < 0.001 |
  ≥25 | 191 (13%) | 661 (13.8%) | 1450 ± (16%) | 0.24 |
  <25 | 1317 (87.3%) | 4116 (86.2%) | 7717 ± (84%) |  |
Male BMI kg/m2 | 23.7 ± 3.7 | 23.7 ± 3.6 | 23.7 ± 3.6 | 0.88 |
  ≥25 | 487 (33%) | 1573 (33%) | 2936 (33%) |  |
  <25 | 992 (67%) | 3135 (67%) | 6038 (67%) |  |
Primary infertility | 742 (49%) | 2278 (48%) | 4302 (47%) | 0.25 |
FSH mIU/ml | 7 (6–8) | 7 (6–8) | 7 (6–8) | 0.44 |
LH mIU/ml | 5 (3–6) | 5 (3–6) | 5 (3–6) | 0.10 |
Estradiol pmol/l | 113 (81–145) | 111 (79–148) | 114 (82–153) | 0.008 |
Progesterone nmol/l | 1.6 (1.1–2.3) | 1.5 (1.1–2.1) | 1.6 (1.1–2.2) | < 0.001 |
Total testosterone nmol/l | 0.8 (0.5–1.1) | 0.7 (0.5–1.1) | 0.79 (0.5–1.1) | 0.22 |
Reason for IVF | ||||
  Tubal factor | 842 (56%) | 2601 (54%) | 4993 (54%) | 0.64 |
  Ovulatory dysfunction | 85 (5.6%) | 316 (6.6%) | 643 (7.0%) | 0.12 |
  Male factor | 447 (30%) | 1586 (33%) | 2960 (32%) | 0.033 |
  Endometriosis | 188 (12.4%) | 571 (12.0%) | 866 (9.4%) | < 0.001 |
  Down-regulation |  |  |  | < 0.001 |
  GnRH agonist | 1310 (86.7%) | 3671 (76.8%) | 7185 (78.4%) |  |
  GnRH antagonist | 182 (12%) | 1019 (21.3%) | 1807 (19.7%) |  |
  Other | 19 (1.3%) | 88 (1.8%) | 178 (1.9%) |  |
Sperm donor | 27 (2.0%) | 77 (2.1%) | 108 (1.4%) | 0.012 |
ICSI | 392 (8.7%) | 1392 (30.9%) | 2723 (60.4%) | 0.01 |
Poor-type endometrium | 60 (4.8%) | 253 (7.5%) | 432 (6.0%) | 0.001 |
Embryo quality |  |  |  | < 0.001 |
  GG | 1360 (92.2%) | 3864 (82.2%) | 7010 (78.1%) |  |
  GP | 97 (6.6%) | 663 (14.1%) | 1257 (14.0%) |  |
  PP | 18 (1.2%) | 175 (3.7%) | 712 (7.9%) |  |
  High education | 703 (46.6%) | 2276 (47.7%) | 3792 (41.4%) | < 0.001 |
Smoking | Â | Â | Â | 0.275 |
  Yes | 5 (0.3%) | 27 (0.6%) | 61 (0.7%) |  |
  No | 1505 (99.7%) | 4747 (99.4%) | 9102 (99.3%) |  |
Endometrial thickness mm | 11.3 ± 2.4 | 11.1 ± 2.4 | 10.7 ± 2.4 | < 0.001 |
  Moderate | 1288 (86%) | 4068 (87%) | 7938 (88%) |  |
  Thin | 18 (1%) | 81 (2%) | 271 (3%) |  |
  Thick | 184 (12%) | 545 (12%) | 824 (9%) |  |
Total number of oocytes | 11.4 ± 4.8 | 10.9 ± 4.9 | 10.8 ± 5.0 | < 0.001 |
Ovarian response |  |  |  | < 0.001 |
  Moderate | 1067 (71%) | 3348 (70%) | 6297 (69%) |  |
  Poor | 155 (10%) | 639 (13%) | 1349 (15%) |  |
  High | 289 (19%) | 790 (17%) | 1519 (17%) |  |