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Table 1 Characteristics of the study population

From: Development and internal validation of the multivariable CIPHER (Collaborative Integrated Pregnancy High-dependency Estimate of Risk) clinical risk prediction model

Patient characteristics Women with no outcome (n = 642), median (IQR) or n (%) Women with outcome (n = 127), median (IQR) or n (%)
Age, years 31 (26–36) 27 (25–32)
Marital status
 Married 346 (53.9) 90 (70.9)
 Single 62 (9.7) 1 (0.8)
 Missing 234 (36.4) 36 (28.3)
BMI, kg/m2 26.4 (24.0–30.0) 26.2 (23.2–29.1)
Prenatal care type
 Public 383 (59.7) 54 (42.5)
 Private 208 (32.4) 73 (57.5)
 Missing 51 (7.9) 0 (0.0)
Gravidity 3 (2–4) 4 (2–5)
Parity 1 (1–2) 2 (1–3)
Details of ICU admission
Reason for admission‡
 Obstetric* 465 (72.4) 77 (60.6)
 Non-obstetric** 263 (41.0) 95 (74.8)
 Missing 3 (0.4) 0 (0.0%)
Timing of admission
 Antepartum 162 (25.2) 46 (36.2)
 Intrapartum 6 (0.9) 1 (0.8)
 Post-partum 459 (71.5) 77 (60.6)
 Missing 15 (2.3) 3 (2.4)
Gestational age in weeks at ICU admission (for women admitted antepartum) 34.4 (28.7–38.0) 30.9 (22.4–35.8)
External ICU transfer, yes 184 (28.7) 21 (16.5)
Length of ICU stay, hours 59.4 (37.0–92.1) 209.9 (110.7–309.4)
Pregnancy outcomes
Early pregnancy loss <24 weeks
 Yes 59 (9.2) 27 (21.3)
 Missing 29 (4.5) 13 (10.2)
Stillbirth 33 (5.1) 24 (18.9)
Livebirth 459 (71.5) 55 (43.3)
Mode of birth
 Vaginal 96 (19.8) 25 (30.5)
 Caesarean 387 (79.8) 57 (69.5)
 Missing 2 (0.4) 0 (0.0)
Birth weight, g 2555 (1700–3250) 2100 (1415–2700)
  1. Abbreviations: BMI body mass index, ICU intensive care unit, IQR interquartile range
  2. *Obstetric reasons for admission included shock, massive postpartum hemorrhage, peripartum cardiomyopathy, amniotic fluid embolism, acute respiratory distress secondary to antepartum hemorrhage, pulmonary edema secondary to pre-eclampsia, eclampsia, septic abortion, other septic complications, and surgical trauma.
  3. **Non-obstetric reasons for admission included cardiac arrhythmia, pericardial effusions, cardiogenic pulmonary edema, pulmonary hypertension, cardiac arrest, pneumonia, respiratory failure or arrest, gastrointestinal perforation/obstruction, diabetic keto-acidosis, deep venous thrombosis, thrombotic thrombocytopenic purpura, posterior reversible encephalopathy syndrome, and severe infection with sepsis
  4. ‡ reasons are not mutually exclusive