Preterm birth factors during different trimesters using Cox regression model
| Antidepressants and trimesters | Population | Proportion (%) | 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 |
| First trimester | 1107 | 61.88 | 55 | 10,461.37 | 5.26 | 1.650 | 1.248 to 2.132 | <0.001 |
| Ssecond trimester | 345 | 19.28 | 15 | 3053.65 | 4.91 | 1.431 | 1.043 to 1.981 | 0.007 |
| Third trimester | 337 | 18.84 | 17 | 2858.57 | 5.95 | 2.009 | 1.675 to 2.587 | <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; HR, hazard ratio; PM, person-month.