Table 2.

Associations and derived risk scores for comorbidities in relation to non-transfusion severe maternal morbidity (using training set of births, n = 70,572)

Risk factor for SMM*	Rate of SMM* (%)	Crude RR	aRR** (95% CI)	Risk Score
Pulmonary Hypertension	21.4	11.5 (6.9–19.2)	4.8 (4.5–5.2)	7
Hematologic Disorder	7.0	3.3 (2.6–4.1)	2.9 (2.5–3.4)	5
Chronic Renal Disease	6.1	2.8 (2.1–3.7)	1.9 (1.7–2.2)	3
Cardiac Disease	5.9	2.9 (2.5–3.3)	2.3 (2.0–2.7	4
Chronic Hypertension	5.4	2.7 (2.3–3.1)	2.4 (2.1–2.7)	4
Connective Tissue Disease	4.6	2.1 (1.6–2.7)	1.5 (1.2–1.8)	2
Prior Uterine Surgery (Non-Cesarean)	4.4	2.0 (1.7–2.4)	1.6 (1.4–1.9)	2
Epilepsy	4.1	1.8 (1.1–3.1)	1.5 (1.3–1.7)	2
Uterine Fibroids	4.0	1.9 (1.7–2.1)	1.6 (1.4–1.9)	2
Diabetes Mellitus	3.6	1.6 (1.3–2.0)	1.4 (1.2–1.8)	2
Substance Use Disorder	3.9	1.7 (1.3–2.2)	1.4 (1.1–1.7)	1
Prior Cesarean Delivery	3.7	1.7 (1.4–2.0)	1.3 (1.1–1.6)	1
Age 40 Years or Older	3.4	1.6 (1.4–1.8)	1.4 (1.2–1.6)	1
Gastrointestinal Disease	3.4	1.6 (1.4–1.8)	1.3 (1.2–1.6)	1
Preconception anemia	3.3	1.5 (1.3–1.7)	1.2 (1.1–1.5)	1
Major Mental Health Disorder	3.2	1.5 (1.3–1.6)	1.3 (1.1–1.4)	1
Asthma	3.1	1.4 (1.2–1.7)	1.3 (1.1–1.5)	1
Endometriosis	3.1	1.4 (1.2–1.6)	NS	NS
Thyroid disease	2.6	1.1 (0.99–1.3)	NS	NS
Polycystic Ovarian Syndrome	2.2	0.96 (0.8–1.1)	NS	NS

SMM, severe maternal morbidity; aRR, adjusted risk ratio

^*Excluding cases with blood transfusion as the only SMM indicator

^**Adjusted for delivery year and other comorbidities using data-adaptive algorithms