Appendix Table 1.
International Classification of Diseases-9th Edition of exposure variable, main covariates and outcomes
| Exposure, main covariates and outcomes | ICD-9 codes used |
|---|---|
| Obstructive Sleep apnea | 780.53; 780.57; 780.51; 327.2; 327.23, |
| Obesity | 278.0; 278.01, 278.03; 649.1; 79391; V853; V854; V855.4 |
| Pre-gestational hypertension | 401; 402; 403; 404; 405; 642.0; 642.1; 642.2; 642.7 |
| Pre-gestational diabetes | 250; 249 |
| Hypertension of pregnancy | 642.3 |
| Preeclampsia | 642.4; 642.5 |
| Eclampsia | 642.6 |
| Gestational diabetes | 648 |
| Pulmonary embolism | 415.1 |
| Cardiomyopathy | 425; 6745 |
| Congestive heart failure | 402.01; 402.11; 402.91; 428; 398.91 |
| Acute pulmonary edema | 518.4 |
| Stroke | 431, 433, 430, 432, 434 |
| Wound complications | 674.1; 674.3; 998.3; 998.5 |
| Hysterectomy (procedure code) | 683–689 |
| Poor fetal growth (Intrauterine Growth Restriction) | 656.5 |
| Stillbirth | 656.4 |