Risk of preterm birth stratified by type and dosage of antidepressants
| Population | Event | PMs | Rate (per 103 PMs) | Adjusted HR* | 95% CI | P value | |
| Without antidepressants | 1789 | 55 | 16,381.25 | 3.36 | Reference | ||
| With antidepressants | 1789 | 87 | 16,373.60 | 5.31 | 1.762 | 1.351 to 2.294 | <0.001 |
| SSRIs, <1 DDD | 52 | 1 | 306.60 | 3.26 | 1.082 | 1.003 to 2.401 | 0.047 |
| SSRIs, ≥1/<2 DDD | 134 | 7 | 1512.77 | 4.63 | 1.537 | 1.175 to 2.004 | <0.001 |
| SSRIs, ≥2 DDD | 222 | 13 | 2339.87 | 5.56 | 1.835 | 1.418 to 2.398 | <0.001 |
| TCAs, <1 DDD | 50 | 2 | 501.98 | 3.98 | 1.321 | 1.024 to 1.732 | 0.015 |
| TCAs, ≥1/<2 DDD | 114 | 5 | 1215.79 | 4.11 | 1.363 | 1.053 to 1.810 | <0.001 |
| TCAs, ≥2 DDD | 216 | 13 | 2305.90 | 5.64 | 1.868 | 1.431 to 2.507 | <0.001 |
| SNRIs, <1 DDD | 62 | 2 | 512.10 | 3.91 | 1.295 | 1.019 to 1.699 | 0.018 |
| SNRIs, ≥1/<2 DDD | 168 | 6 | 1482.89 | 4.05 | 1.342 | 1.031 to 1.803 | 0.003 |
| SNRIs, ≥2 DDD | 253 | 14 | 2767.80 | 5.06 | 1.673 | 1.287 to 2.188 | <0.001 |
| Others, <1 DDD | 61 | 2 | 459.70 | 4.35 | 1.445 | 1.113 to 1.887 | <0.001 |
| Others, ≥1/<2 DDD | 198 | 7 | 1035.90 | 6.76 | 2.239 | 1.715 to 2.964 | <0.001 |
| Others, ≥2 DDD | 259 | 15 | 1932.31 | 7.76 | 2.574 | 1.930 to 3.385 | <0.001 |
*Adjusted for variables including age, income-related insurance premium, hospital types, urbanization levels, nulliparity or multiparity, multiple gestation, diabetes mellitus, hypertension, dyslipidemia, uteroplacental ischemia or hemorrhage, reproductive tract infection, pre-eclampsia, eclampsia, placenta previa, abruptio placenta, polycystic ovaries, hypogonadism, hypergonadism, pregnancy with history of infertility, morbid obesity or being overweight, and anxiety disorders.
CI, confidence interval; DDD, defined daily dose; HR, hazard ratio; PM, person-month; SNRI, serotonin norepinephrine reuptake inhibitor; SSRI, selective serotonin reuptake inhibitor; TCA, tricyclic antidepressant.