Table 32, GRADE findings for predictive value of published categorisation of fetal heart rate traces for adverse neonatal outcomes - Addendum to intrapartum care: care for healthy women and babies

Table 32GRADE findings for predictive value of published categorisation of fetal heart rate traces for adverse neonatal outcomes

Quality assessment						Definition of outcome	Stage of labour	Total number of women & baby pairs	Measure of diagnostic accuracy (95% CI)				Quality
Number of studies	Design	Risk of bias	Inconsistency	Indirectness	Imprecision	Definition of outcome	Stage of labour	Total number of women & baby pairs	Sensitivity	Specificity	Positive likelihood ratio	Negative likelihood ratio	Quality
Krebs score (abnormal versus normal)
1 study (Spencer 1997)	Case control	Serious¹	No serious inconsistency	Serious²^,³	No serious imprecision	Encephalopathy	First 30 minutes of tracing	73	5.71% (1.98 to 13.40)^a	96.97% (96.97 to 100)^a	1.80 (0.11 to 7.74)^a	0.97 (0.90 to 1.17)^a	Very low
FIGO classification (abnormal versus normal)
1 study (Spencer 1997)	Case control	Serious¹	No serious inconsistency	Serious²^,³	No serious imprecision	Encephalopathy	First 30 minutes of tracing	73	50% (34.10 to 65.90)^a	74.29% (59.81 to 88.77)^a	1.94 (1.01 to 3.71)^a	0.67 (0.46 to 0.97)^a	Very low
Krebs score (abnormal versus normal)
1 study (Spencer 1997)	Case control	Serious¹	No serious inconsistency	Serious²^,³	No serious imprecision	Encephalopathy	Last 30 minutes of tracing	54	41.38% (23.45 to 59.30)	84% (69.63 to 98.37)	2.58 (0.95 to 7.01)^a	0.69 (0.49 to 0.99)^a	Very low
FIGO classification (abnormal versus normal)
1 study (Spencer 1997)	Case control	Serious¹	No serious inconsistency	Serious²^,³	No serious imprecision	Encephalopathy	Last 30 minutes of tracing	67	88.89% (78.2 to 99.16)^a	48.39% (30.79 to 65.98)^a	1.72 (1.20 to 2.46)^a	0.22 (0.08 to 0.61)^a	Very low
“Ominous” first stage CTG (No definition reported)
1 study (Gaffney 1994)	Cohort	No serious risk of bias	No serious inconsistency	Serious⁴	No serious imprecision	Encephalopathy	1st stage	96	32.50% (17.98 to 47.02)^a	92.31% (85.06 to 99.55)^a	4.22 (1.49 to 11.91)^a	0.73 (0.58 to 0.9)^a	Low
“Ominous” second stage CTG (No definition reported)
1 study (Gaffney 1994)	Cohort	No serious risk of bias	No serious inconsistency	Serious⁴	No serious imprecision	Encephalopathy	2nd stage	96	45.65% (31.26 to 60.05)^a	70.31% (59.12 to 81.51)^a	1.53 (0.94 to 2.51)^a	0.77 (0.56 to 1.05)^a	Low
Pattern 1 (absent baseline variability [≥ 1 cycle] usually with late and/or prolonged deceleration)^c
1 study (Low 1999)	Case control	Serious¹	No serious inconsistency	Serious³	No serious imprecision	Asphyxia	NR	142	17%	98%	8.50	0.84	Very low
Pattern 2 (minimal baseline variability [≥ 2 cycles] and late and/or prolonged deceleration [≥ 2 cycles])^c
1 study (Low 1999)	Case control	Serious¹	No serious inconsistency	Serious³	No serious imprecision	Asphyxia	NR	142	46%	89%	4.18	0.60	Very low
Pattern 3 (minimal baseline variability [≥ 2 cycles] or late and/or prolonged deceleration [≥ 2 cycles])^c
1 study (Low 1999)	Case control	Serious¹	No serious inconsistency	Serious³	No serious imprecision	Asphyxia	NR	142	75%	57%	1.70	0.43	Very low
Pattern 4 (minimal baseline variability [1 cycles] and/or late and/or prolonged deceleration [1 cycle])^c
1 study (Low 1999)	Case control	Serious¹	No serious inconsistency	Serious³	No serious imprecision	Asphyxia	NR	142	93%	29%	1.30	0.29	Very low
Fetal sleep pattern ≥ 50% of the tracing (NICHD classification) (fetal sleep pattern not defined)
1 study (Menihan 2006)	Case control	Serious¹	No serious inconsistency	Serious³	No serious imprecision	Sudden infant death	NR	142	40% (21.9 to 61.3)^a	45.7% (34.6 to 57.3)^a	0.70 (0.41 to 1.31)^a	1.31 (0.84 to 2.03)^a	Very low
“Abnormal” FHR pattern (NICHD classification)
1 study (Hadar 2001)	Cohort	Serious⁹	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical artery pH 7.1, 7.2 + Base deficit > 12	1st stage	601	78.3% (70.4 to 86.1)^a	55.9% (51.5 to 60.3)^a	1.77 (1.54 to 2.04)^a	0.38 (0.26 to 0.56)^a	Moderate
Category III (versus category 1) (NICHD classification 2008)
1 study (Graham 2014)	Case control	Very serious⁵	No serious inconsistency	No serious indirectness	Very serious⁶	Whole-body hypothermia treatment for suspected moderate to severe encephalopathy	Last 1 hour tracing before birth	117	55.6% (22.7 to 84.7)^b	87.5% (46.7 to 99.3)^b	4.44 (0.65 to 30.44)^b	0.51 (0.24 to 1.09)^b	Very low
Category II (versus category 1) (NICHD classification 2008)
1 study (Graham 2014)	Case control	Very serious⁵	No serious inconsistency	No serious indirectness	Serious⁷	Whole-body hypothermia treatment for suspected moderate to severe encephalopathy	Last 1 hour tracing before birth	117	88.2% (71.6 to 96.2)^b	9.1% (4.0 to 18.4)^b	0.97 (0.84 to 1.12)^b	1.29 (0.40 to 4.19)^b	Very low
Indeterminate FHR pattern (Category II, NICHD classification 2008)
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness	No serious imprecision¹¹	Umbilical artery pH ≤7.2	In early labour during a 20–40 minute period	Mixed population of both low- and high-risk pregnancies N=818 (normal n=659, indeterminate n=159)	40.6% (24.2 to 59.2)	69.8% (62.5 to 76.2)	1.34 (0.84 to 2.16)^b	0.85 (0.64 to 1.14)^b	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness	No serious imprecision¹¹	NICU admission	In early labour during a 20–40 minute period	Mixed population of both low- and high-risk pregnancies N=818 (normal n=659, indeterminate n=159)	35.7% (22.0 to 52.0%)	81.4% (78.5 to 84.1%)	1.92 (1.25 to 2.96)^b	0.79 (0.63 to 1.00)^b	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness¹¹	No serious imprecision	NICU admission excluding preterm birth	In early labour during a 20–40 minute period	Mixed population of both low- and high-risk pregnancies N=818 (normal n=659, indeterminate n=159)	31.3%	81.9%	1.73^b	0.84^b	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness	Serious imprecision¹²	Neonatal death	In early labour during a 20–40 minute period	Mixed population of both low- and high-risk pregnancies N=818 (normal n=659, indeterminate n=159)	100% (19.8 to 100)	80.8% (77.8 to 83.4)	5.2 (4.52 to 5.98)^b	0 (NA)	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness¹¹	No serious imprecision	Umbilical artery pH ≤7.2	In early labour during a 20–40 minute period	Low-risk population only N=492 (normal n=410, indeterminate n=82)	26.7% (8.9 to 55.2)	83.7% (80.0 to 86.8)	1.63 (0.69 to 3.87)^b	0.88 (0.65 to 1.19)^b	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness¹¹	No serious imprecision	NICU admission	In early labour during a 20–40 minute period	Low-risk population only N=492 (normal n=410, indeterminate n=82)	16.7% (4.4 to 42.2)	83.3% (79.6 to 86.5)	1.00 (0.35 to 2.86)^b	1.00 (0.81 to 1.23)^b	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness	No serious imprecision¹¹	NICU admission excluding preterm birth	In early labour during a 20–40 minute period	Low-risk population only N=492 (normal n=410, indeterminate n=82)	12.5%	83.2%	0.74^b	1.05^b	Low
1 study (Sharbaf 2014)	Prospective cohort	Very serious¹⁰	No serious inconsistency	No serious indirectness	No serious imprecision¹¹	Neonatal death	In early labour during a 20–40 minute period	Low-risk population only N=492 (normal n=410, indeterminate n=82)	NA	83.3% (79.7 to 86.4)	0b (NA)	1.20^b (NA)	Low
“Stressed” or “distressed” FHR patterns (Dellinger classification)
1 study (Dellinger 2000)	Cohort	Serious¹³	No serious inconsistency	No serious indirectness	No serious imprecision	NICU admission	1 hour before birth	898 (normal = 627, stressed n = 263, distressed n = 8)	46%	72%	1.64	0.75	Low
1 study (Dellinger 2000)	Cohort	Serious¹³	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical artery pH < 7	1 hour before birth	898 (normal = 627, stressed n = 263, distressed n = 8)	100%	66%	2.9	0	Low
1 study (Dellinger 2000)	Cohort	Serious¹³	No serious inconsistency	No serious indirectness	No serious imprecision	BE < −11	1 hour before birth	898 (normal = 627, stressed n = 263, distressed n = 8)	100%	66%	2.9	0	Low
“Distressed” FHR patterns (Dellinger classification)
1 study (Dellinger 2000)	Cohort	Serious¹³	No serious inconsistency	No serious indirectness	No serious imprecision	NICU admission	1 hour before birth	635 (normal = 627, distressed n = 8)	9%	99%	9.0	0.91	Low
1 study (Dellinger 2000)	Cohort	Serious¹³	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical artery pH < 7	1 hour before birth	635 (normal = 627, distressed n = 8)	100%	98%	50	0	Low
1 study (Dellinger 2000)	Cohort	Serious¹³	No serious inconsistency	No serious indirectness	No serious imprecision	BE < −11	1 hour before birth	635 (normal = 627, distressed n = 8)	100%	98%	50	0	Low
Presence of 1 poor prognostic feature^d
1 study (Ozden 1999)	Cohort	Serious²	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical cord arterial pH <7.20	NR	167	75%	55%	1.60	0.45	Moderate
Presence of 2 poor prognostic features)^d
1 study (Ozden 1999)	Cohort	Serious²	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical cord arterial pH <7.20	NR	167	55.6%	70.0%	1.83	0.64	Moderate
Presence of 3 poor prognostic features)^d
1 study (Ozden 1999)	Cohort	Serious²	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical cord arterial pH <7.20	NR	167	36.1%	82.5%	2.06	0.77	Moderate
Presence of 4 poor prognostic features^d
1 study (Ozden 1999)	Cohort	Serious²	No serious inconsistency	No serious indirectness	No serious imprecision	Umbilical cord arterial pH <7.20	NR	167	22.2%	90%	2.22	0.86	Moderate
FHR baseline < 110 bpm, baseline variability < 5 bpm and non-reactive trace (NICHD classification)
1 study (Larma 2007)	Case control	Serious¹⁴	No serious inconsistency	Serious³	No serious imprecision	Moderate HIE	Last hour of tracing	214	7.7%	98.9%	6.36	0.94	Very low

BE base excess; CI confidence interval; CTG cardiotocography; FHR fetal heart rate; FIGO International Federation of Obstetrics and Gynaecology; HIE hypoxic ischaemic encephalopathy; NA not applicable; NICHD National Institute of Child Health and Human Development; NICU neonatal intensive care unit; NR not reported

a

Calculated by the 2014 NCC-WCH technical team

b

Fetal asphyxia was classified as mild, moderate, or severe on the basis of umbilical artery base deficit (cut off >12 mmol/l) and neonatal encephalopathy and other organ system complications

FHR criteria predictive of fetal asphyxia:

Absent or minimal baseline variability and late or prolong decelerations

The FHR patterns are based on the findings in six 10 minute cycles of FHR recording

Absent baseline variability, usually with repeat cycles (≥ 2) of the late or prolonged decelerations
Repeat cycles (≥ 2) of both minimal baseline variability and late or prolonged decelerations
Repeat cycles (≥ 2) of either minimal baseline variability or late or prolonged decelerations
One cycle of either minimal baseline variability or late or prolong decelerations
No cycle of either minimal baseline variability or late or prolonged decelerations

c

Calculated by the 2017 NGA technical team

d

Variable deceleration classified into 7 subtypes according to poor prognostic features (PPFs):

Loss of primary acceleration
Loss of secondary acceleration
Loss of variability during deceleration
Slow return to baseline
Biphasic deceleration
Prolonged secondary acceleration
Prolonged deceleration

1

Unclear who evaluated the traces

2

Small study with low statistical power

3

Unclear if women with pre-existing medical conditions were excluded

4

Half of the study population had one or more antenatal complicating factor

5

Unclear if the assessors were blinded to outcomes

6

High risk of bias due to study design and timing

7

95% CI for the positive likelihood ratio crosses 5 and 10, and for the negative likelihood ratio crosses 0.5

8

95% CI for the negative likelihood ratio crosses 0.5

9

Unclear if consecutive enrolment of participants was performed, no blinding of assessors for CTG tracing findings when outcome was assessed, late preterm births were included, and events independent of CTG tracing may have influenced the outcome

10

1% of the population were late preterm (> 34 and < 37 weeks of gestation)

11

95% CI for the positive LR crosses 5

12

Under-powered cohort due to imbalance in number of participants in groups

13

Exclusion criteria not specified, high risk of selection bias

From: Appendix I, GRADE tables

Addendum to intrapartum care: care for healthy women and babies.

Clinical Guideline, No. 190.1.

National Guideline Alliance (UK).

London: National Institute for Health and Care Excellence (NICE); 2017 Feb.

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