Table 3.
Baseline characteristics of the study cohort according to pregnancy status, after propensity score matching (group 1)
| Non-pregnancy after breast cancer (n=992) | Pregnancy after breast cancer (n=992) | p-value | All (n=1,984) | |
|---|---|---|---|---|
| Age at cancer diagnosis (yr) | ||||
| ≤ 35 | 788 (79.4) | 788 (79.4) | > 0.99 | 1,576 (79.4) |
| 36-45 | 204 (20.6) | 204 (20.6) | 408 (20.6) | |
| Chemotherapy | ||||
| Yes | 318 (32.1) | 318 (32.1) | > 0.99 | 636 (32.1) |
| No | 674 (67.9) | 674 (67.9) | 1,348 (67.9) | |
| Radiotherapy | ||||
| Yes | 209 (29.2) | 209 (29.2) | > 0.99 | 580 (29.2) |
| No | 702 (70.8) | 702 (70.8) | 1,404 (70.8) | |
| Ovarian preservation (missing=1,348) | ||||
| Yes | 0 | 2 (0.6) | 0.367 | 2 (0.3) |
| No | 318 (100) | 316 (99.4) | 634 (99.7) | |
| Trastuzumab therapy | ||||
| Yes | 7 (0.7) | 13 (1.3) | 0.178 | 20 (1.0) |
| No | 985 (99.3) | 979 (98.7) | 1,964 (99.0) | |
| Adjuvant hormonal therapy | ||||
| Yes | 366 (36.9) | 366 (36.9) | > 0.99 | 732 (36.9) |
| No | 626 (63.1) | 626 (63.1) | 1,252 (63.1) | |
| Hormone therapy duration (day) | ||||
| Mean±SD | 1,411.8±625.9 | 1,061.9±709.9 | < 0.001 | 1,236.8±691.3 |
| Median | 1,631 | 1,059 | 1,459 | |
| Time between surgery and conception (day) | ||||
| Mean±SD | - | 1,176.4±868.6 | < 0.001 | 1,176.4±868.6 |
| Median | - | 1,061 | 1,061 | |
| SEER stage (missing=1,278) | ||||
| Localized | 41 (41.4) | 385 (59.1) | < 0.001 | 382 (49.0) |
| Regional | 37 (37.4) | 183 (28.1) | 271 (34.7) | |
| Distant | 3 (3.0) | 9 (1.4) | 22 (2.8) | |
| Unknown | 18 (18.2) | 74 (11.4) | 105 (13.5) |
Values are presented as mean±SD or number (%). SEER, Surveillance, Epidemiology, and End Results; SD, standard deviation.