Table H.5.2GRADE findings for antenatal diagnosis of placenta accreta compared with no antenatal diagnosis (maternal outcomes)

Quality assessmentSummary of findings
No. of womenEffect
No. of studiesDesignLimitationsInconsistencyIndirectnessImprecisionOther considerationsAntenatal diagnosis of placenta accretaNo antenatal diagnosis of placenta accretaRelative (95% CI)Absolute (95% CI)Quality
Estimated blood loss
1 study

(Warshak et al., 2009)
observational studyserious2no serious inconsistencyserious1,5no serious imprecisionnoneMean (litre) ± SD

2.3 ± 1.7

n = 62
Mean (litre) ± SD

2.9 ± 1.8

n = 37
Not calculable (NC)MD 0.6 lower

(1.32 lower to 0.12 higher)

p = 0.053
Very low
1 study

(Wong et al., 2008)
observational studySerious2no serious inconsistencyserious3,4no serious imprecisionnoneMean (litre) ± SD

1.4 ± 1.0

n = 7
Mean (litre) ± SD

3.6 ± 1.3

n = 9
NCMD 2.20 lower

(3.48 lower to 0.92 lower)

p = 0.003
Very low
Number of units of blood transfused
1 study

(Warshak et al., 2009)
observational studyserious2no serious inconsistencyserious1,5no serious imprecisionnoneMean ± SD

4.7 ± 2.2

n = 62
Mean ± SD

6.9 ± 1.8

n = 37
NCMD 2.20 lower

(3.05 lower to 1.35 lower)

p = 0.02
Very low
1 study

(Wong et al., 2008)
observational studyserious2no serious inconsistencyserious3,4no serious imprecisionnone2.3 ± 2.9

n = 7
5.1 ± 2.9

n = 9
NCMD 2.80 lower

(5.93 lower to 0.33 higher)

p = 0.07
Very low
Emergency hysterectomy
1 study

(Wong et al., 2008)
observational studyserious2no serious inconsistencyserious3,4no serious imprecisionnone1/7 (14%)

n = 7
9/9

(100%)

n = 9
RR 0.14

(0.02 to 0.55)
857 fewer per 1000

(from 975 fewer to 435 fewer)*

p = 0.001
Very low
Intensive care unit [ICU] admission
1 study

(Warshak et al., 2009)
observational studyserious2no serious inconsistencyserious1,5serious5none43/62

(69%)
22/37

(59%)
RR 1.16

(0.86 to 1.64)*
98 more per 1000

(from 92 fewer to 293 more)*

p = 0.49
Very low
1 study

(Wong et al., 2008)
observational studyserious2no serious inconsistencyserious3,4serious5,6none1/7

(14%)
1/9

(11%)
RR 1.28

(0.14 to 11)*
31 more per 1000

(from 344 fewer to 443 more)*

p = 1.0
Very low
Length of hospital stay
1 study

(Warshak et al., 2009)
observational studyserious2no serious inconsistencyserious1,5no serious imprecisionnone7.4 days

(SD 1.8)

n = 62
5.5 days

(SD 1.6)

n = 37
NCMD 1.90 higher

(1.19 lower to 2.61 higher)

p = 0.92
Very low
1 study

(Wong et al., 2008)
observational studyserious2no serious inconsistencyserious3,4no serious imprecisionnone8.6 days

(SD 1.36)

n = 7
9.9 days

(SD 4.9)

n = 9
NCMD 1.30 lower

(5.41 lower to 2.81 higher)

P value not reported
Very low
Bladder injuries
1 study

(Warshak et al., 2009)
observational studyserious2no serious inconsistencyserious1,5serious6none14/62

(22%)
3/37

(8.1%)
RR 2.78

(0.94 to 8.71)*
144 more per 1000

(from 11 fewer to 280 more)*
Very low
1 study

(Wong et al., 2008)
observational studyserious2no serious inconsistencyserious3,4serious6none1/7

(14%)
1/9

(11%)
RR 1.28

(0.14 to 11)*
31 more per 1000

(from 344 fewer to 443 more)*
Very low
1

15% of the total population (n = 15/99) had no previous CS.

2

Small size study with low statistical power

3

Twelve out of the total population (n = 12/16) had previous CS.

4

Eleven out of the total population (n = 11/16) had placenta praevia in their current pregnancy.

5

71 out of the total population (n = 71/99) had placenta praevia in their current pregnancy.

6

Wide CI

*

Calculated by NCC-WCH technical team

From: Appendix H, GRADE tables

Cover of Caesarean Section
Caesarean Section.
NICE Clinical Guidelines, No. 132.
National Collaborating Centre for Women's and Children's Health (UK).
London: RCOG Press; 2011 Nov.
Copyright © 2011, National Collaborating Centre for Women's and Children's Health.

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