Condition, (%) Multiple gestation = 266,751 Singleton gestation = 12,257,367 OR (95% CI) valuePulmonary disease Asthma 10,347 (3.9) 394,749 (3.2) 1.21 (1.19, 1.24) <0.0001 Endocrine disorders Diabetes (nongestational) 3242 (1.2) 127,728 (1.0) 1.17 (1.13, 1.21) <0.0001 Thyroid disorder 11,533 (4.3) 286,009 (2.3) 1.89 (1.86, 1.93) <0.0001 Autoimmune disorders Systemic lupus erythematosus 420 (0.16) 13,930 (0.11) 1.39 (1.26, 1.53) <0.0001 Collagen vascular disease/rheumatoid arthritis 469 (0.18) 14,932 (0.12) 1.44 (1.32, 1.58) <0.0001 HIV 75 (0.028) 3541 (0.029) 0.98 (0.77, 1.22) 0.85 Hematologic disorders Thrombophilia/APS 2609 (1.0) 61,908 (0.50) 1.95 (1.87, 2.02) <0.0001 Anemia 47,106 (17.7) 1,308,237 (10.7) 1.80 (1.78, 1.81) <0.0001 Thrombocytopenia 5439 (2.0) 108,169 (0.9) 2.34 (2.27, 2.40) <0.0001 Drugs/alcohol/tobacco Drug use 3029 (1.1) 159,237 (1.3) 0.87 (0.84, 0.90) <0.0001 Alcohol use 258 (0.10) 13,392 (0.11) 0.89 (0.78, 1.00) 0.056 Tobacco 14,399 (5.4) 772,584 (6.3) 0.85 (0.83, 0.86) <0.0001 Chronic hypertension/renal failure Chronic hypertension 8040 (3.0) 236,910 (1.9) 1.58 (1.54, 1.61) <0.0001 Chronic renal failure 198 (0.07) 4719 (0.04) 1.93 (1.66, 2.21) <0.0001