Descriptive characteristics of study cohorts of assisted reproductive technology (ART) treatments in women with UC, CD and without IBD during the study period of 1 January 1994 through 2013
| Characteristics | Exposed cohort (embryo transfers in women with UC) (N=1360)*† | Exposed cohort (embryo transfers in women with CD) (N=554)*‡ | Unexposed cohort (embryo transfers in women without IBD) (N=148 540)*§ |
|---|---|---|---|
| Age at embryo transfer | |||
| Median (25–75 centiles) | 33 (30–36) | 32 (30–35) | 33 (30–37) |
| Partner's age at embryo transfer | |||
| Median (25–75 centiles) | 35.5 (32–39) | 35 (31–37) | 35 (32–39) |
| Female/male factor | |||
| Female factor, N (%) | 442 (34.5) | 234 (46.6) | 41 011 (30.1) |
| Male factor, N (%) | 269 (21.0) | 83 (16.5) | 43 610 (32.0) |
| Mixture of factors/idiopathic N (%) | 570 (44.5) | 185 (36.9) | 51 852 (38.0) |
| Type of preceding treatment | |||
| IVF, N (%) | 718 (53.0) | 290 (52.6) | 72 971 (49.3) |
| ICSI, N (%) | 403 (29.7) | 166 (30.1) | 51 237 (34.6) |
| FER, N (%) | 234 (17.3) | 95 (17.2) | 23 713 (16.0) |
| BMI | |||
| <18.5 (underweight), N (%) | 15 (2.3) | 16 (7.2) | 1765 (3.1) |
| 18.5–24.99 (normal), N (%) | 450 (69.7) | 125 (56.3) | 37 082 (64.4) |
| 25.00–29.99 (overweight), N (%) | 134 (20.7) | 69 (31.1) | 13 157 (22.9) |
| ≥30.00 (obese), N (%) | 47 (7.3) | 12 (5.4) | 5548 (9.6) |
| Smoking at the time of embryo transfer | |||
| Non-smoker, N (%) | 617 (93.8) | 192 (87.3) | 51 819 (90.0) |
| Smoker, N (%) | 41 (6.2) | 28 (12.7) | 5773 (10.0) |
| Alcohol | |||
| No, N (%) | 304 (52.0) | 135 (70.3) | 29 367 (54.5) |
| Yes, N (%) | 281 (48.0) | 57 (29.7) | 24 548 (45.5) |
| Calendar year of infertility treatment | |||
| 1994–1998, N (%) | 110 (8.1) | 84 (15.2) | 24 016 (16.2) |
| 1999–2003, N (%) | 254 (18.7) | 128 (23.1) | 35 899 (24.2) |
| 2004–2008, N (%) | 469 (34.5) | 188 (33.9) | 44 467 (29.9) |
| 2009–2013, N (%) | 527 (38.8) | 154 (27.8) | 44 158 (29.7) |
| Parity | |||
| 0, N (%) | 169 (62.4) | 65 (70.7) | 24 102 (69.0) |
| 1+, N (%) | 102 (37.6) | 27 (29.3) | 10 845 (31.0) |
| Comorbidity at embryo transfer | |||
| No comorbidity, N (%) | 1202 (88.4) | 476 (85.9) | 136 982 (92.2) |
| Some comorbidity, N (%) | 158 (11.6) | 78 (14.1) | 11 558 (7.8) |
| Duration of UC/CD at time of embryo transfer | |||
| Median (25–75 centiles) | 8 (4–12) | 9 (4–13) | – |
| UC/CD operations before time of embryo transfer¶ | |||
| No, N (%) | 891 (65.5) | 199 (35.9) | – |
| Yes, N (%) | 469 (34.5) | 355 (64.1) | – |
| Number of UC operations before embryo transfer¶ | |||
| 1, N (%) | 242 (51.6) | – | – |
| 2–3, N (%) | 227 (48.4) | – | – |
| Number of CD operations before embryo transfer¶ | |||
| 1, N (%) | – | 175 (49.3) | – |
| 2–3, N (%) | – | 159 (44.8) | – |
| >3, N (%) | – | 21 (5.9) | – |
*Number of women in exposed UC cohort=432, in exposed CD cohort=182 and in unexposed cohort=52 489.
†Missing (%), women with UC: partner's age (42.5), female/male factor (5.8), type of treatment (0.4), parity (80.1), BMI (52.5), smoking at the time of embryo transfer (51.6), alcohol (57.0).
‡Missing (%), women with CD: age of partner (49.6), fertility factor (9.4), ART treatment (0.5), parity (83.4), BMI (59.9), smoking at the time of embryo transfer (60.3), alcohol (65.3).
§Missing (%), women with no IBD: partner's age (53.4), female/male factor (8.1), type of treatment (0.4), parity (76.5), BMI (61.3), smoking at the time of embryo transfer (61.2), alcohol (63.7).
¶It is possible to have more than one type of UC or CD operation on the same day.
BMI, body mass index; CD, Crohn's disease; FER, frozen-thawed embryos; IBD, inflammatory bowel disease; ICSI, intracytoplasmic sperm injection; IVF, in vitro fertilisation; UC, ulcerative colitis.