|
Number and data source of included studies
|
|
USa data (n = 50)
|
|
National Inpatient Sample
|
17,18,26,39,45,48,58,72
|
|
National Readmission Database: 21 states
|
32
|
|
CMSb Medicaid (MAX) data
|
22
|
|
US claims data
|
27,70
|
|
US perinatal data networks
|
28,43
|
|
Hospital discharge data: 7 states
|
33
|
|
Hospital discharge data: Illinois
|
84
|
|
Hospital discharge data: Maryland
|
81
|
|
Hospital discharge ± birth certificate data: New York State
|
19,44,53
|
|
Hospital discharge + birth certificate data: 3 states
|
29
|
|
Hospital discharge + birth certificate data: Iowa
|
38
|
|
Hospital discharge + birth certificate data: New York City
|
46,47,49,50,78
|
|
Hospital discharge, birth, ± death certificate data: California
|
36,40,52,55-57,68,69,76
|
|
Hospital discharge, birth, + death certificate data: Georgia
|
91
|
|
Hospital discharge, birth, ± death certificate data: Washington
|
42,62–64
|
|
Hospital discharge + medical record data: 16 California hospitals
|
51
|
|
Hospital discharge + medical record data: Massachusetts
|
21
|
|
Hospital discharge + SARTc + vital statistics data: Massachusetts
|
23
|
|
Birth certificate data: Ohio
|
71
|
|
Birth certificate and SART data: 8 states
|
67
|
|
Medical record data single hospital: California
|
93
|
|
Medical record data single hospital: New York
|
73
|
|
Medical record data single hospital: Missouri
|
83
|
|
Medical record data single hospital: Tennessee
|
41
|
|
Non-US data (n = 31)
|
|
Multiple countries including US
|
60
|
|
Multiple countries not including US
|
90
|
|
Japan
|
16
|
|
Korea
|
75
|
|
Sweden
|
92
|
|
Finland
|
77
|
|
France
|
25,54,88
|
|
Canada: Ontario
|
34,35,80,89
|
|
Canada: British Columbia
|
61,85,86
|
|
Canada: multiple provinces
|
3,8,65,66,74,79,94
|
|
Australia: New South Wales
|
20,24,30,31,37,82,87
|
|
Australia: Victoria
|
59
|
|
Study design and population
|
|
Study design nested case-control (n = 6)
|
|
Yes
|
16,21,34,42,54,88
|
|
Hospital-level risk factors with specific hypotheses (n = 8)
|
|
Patient-level data adjusted for clustering among hospitals
|
19,27,29,32,39
|
|
Hierarchical models
|
36,91
|
|
Hospital-level data
|
49
|
|
Delivery discharges limited by: (n = 22)
|
|
Community hospitals
|
36
|
|
Annual delivery volume less than 1000
|
45
|
|
Low risk
|
19,40,65,66
|
|
Low risk breech presentation
|
24
|
|
Medicaid eligibility
|
22
|
|
Nulliparous
|
85
|
|
Prior cesarean delivery with parity = 1
|
94
|
|
Prior cesarean delivery ≥3
|
73
|
|
No prior cesarean delivery
|
66
|
|
Cesarean delivery 22–34 gestational weeks
|
25
|
|
Elective cesarean delivery
|
16
|
|
Preterm gestation
|
20,68
|
|
Term laboring patients with prolonged second stage
|
74
|
|
Preeclampsia
|
27
|
|
Hemorrhage
|
80
|
|
Race/ethnicity Hispanic or White
|
46
|
|
Race Black or White
|
47,48
|
|
SMMddefinition CDCe basis [7] (n = 37)
|
|
25 indicators
|
17,18,23,29,33,36,38,42,46-53,58,60,68,69,71,72,75,76,91,93
|
|
18 indicators
|
19,26,27,41,44,55-57,78,83,84
|
|
SMM definition not using CDC basis (n = 44)
|
|
Adapted from other US work (Bateman et al. [22])
|
32,39,45,61–63
|
|
Adapted from Canadian work (Wen et al. [3]/Joseph et al. [8])
|
3,8,22,34,35,66,74,89,94
|
|
Adapted from Australian work (Roberts et al. [8])
|
20,24,30,31,37,59,79,82,87
|
|
Adapted from Swedish work (Wahlberg et al. [92])
|
90,92
|
|
Adapted from Geller et al. (5 factor) [95]
|
43,85
|
|
Death
|
80
|
|
Intensive care unit admission
|
21,25,28,40,53,65,67,71,73
|
|
Other
|
16,54,64,77,86,88
|
|
Sensitivity analysis for use of transfusion in SMM definition (n = 15)
|
|
Yes
|
26,33,38,44,46,47,49,50,55-57,60,78,91,94
|
|
Blood transfusion threshold was 4 units of packed red blood cells (n = 6)
|
|
Yes
|
43,51,54,85,88,93
|
|
Blood transfusion not included in definition (n = 10)
|
|
Yes
|
22,32,37,39,45,77,80,86,90,92
|
|
Key risk factors studied
|
|
General risk factors (no hypotheses) (n = 16)
|
|
Yes
|
3,8,22,38,42-45,52,53,59,60,80,81,83,90
|
|
Patient-level risk factors with specific hypotheses (n = 57)
|
|
Race/ethnicity
|
18,26,33,46-48,50,57,58,72
|
|
BMIf or gestational weight gain
|
35,55,62,71,73,78,86,88
|
|
Maternal age
|
63,76,85
|
|
Preterm birth
|
25,51,68
|
|
Infertility/IVFg/ARTh
|
23,34,54,67,70,93
|
|
Preeclampsia
|
64
|
|
Hemorrhage
|
37
|
|
Obstructive sleep apnea
|
28
|
|
Congenital heart disease
|
79
|
|
Inflammatory bowel disease
|
87
|
|
Autoimmunity
|
30
|
|
Idiopathic arthritis
|
31
|
|
Rural vs. urban
|
61
|
|
Maternal birthplace or immigration country
|
89,92
|
|
Amphetamine/opioid use
|
17
|
|
Route of delivery
|
20,21,24,41,56,66,74,77,84,94
|
|
Induction of labor
|
40,65,82
|
|
Anesthesia for cesarean delivery
|
16
|
|
Off-hours delivery
|
69,75
|
|
Hospital-level risk factors with specific hypotheses (n = 8)
|
|
Delivery volume
|
27,29,39
|
|
Level of care
|
32,91
|
|
Percent midwives delivering
|
19
|
|
Presence of laborist
|
36
|
|
Hospital quality indicators
|
49
|
