Intrapartum fetal scalp lactate sampling for fetal assessment in the presence of a non-reassuring fetal heart rate trace (Review)

East, Christine E, Leader, Leo R., Sheehan, Penelope, Henshall, Naomi E., Colditz, Paul B. and Lau, Rosalind (2015) Intrapartum fetal scalp lactate sampling for fetal assessment in the presence of a non-reassuring fetal heart rate trace (Review). Cochrane Database of Systematic Reviews, 2015 5: CD006174-CD006174. doi:10.1002/14651858.CD006174.pub3

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Author East, Christine E
Leader, Leo R.
Sheehan, Penelope
Henshall, Naomi E.
Colditz, Paul B.
Lau, Rosalind
Title Intrapartum fetal scalp lactate sampling for fetal assessment in the presence of a non-reassuring fetal heart rate trace (Review)
Journal name Cochrane Database of Systematic Reviews   Check publisher's open access policy
ISSN 1469-493X
Publication date 2015-05-01
Year available 2015
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1002/14651858.CD006174.pub3
Open Access Status File (Publisher version)
Volume 2015
Issue 5
Start page CD006174
End page CD006174
Total pages 39
Place of publication Oxford, United Kingdom
Publisher John Wiley and Sons
Language eng
Subject 2736 Pharmacology (medical)
Abstract Background
Formatted abstract
Background
Fetal scalp blood sampling for lactate estimation may be considered following identification of an abnormal or non-reassuring fetal heart rate pattern. The smaller volume of blood required for this test, compared with the more traditional pH estimation, may improve sampling rates. The appropriate use of this practice mandates systematic review of its safety and clinical effectiveness prior to widespread introduction.

Objectives
To evaluate the effectiveness and risks of fetal scalp lactate sampling in the assessment of fetal well-being during labour, compared with no testing or alternative testing.

Search methods
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015).

Selection criteria
All published and unpublished randomised and quasi-randomised trials that compared fetal scalp lactate testing with no testing or alternative testing to evaluate fetal status in the presence of a non-reassuring cardiotocograph during labour.

Data collection and analysis

We used the standard methodological procedures of the Cochrane Pregnancy and Childbirth Group. Two review authors independently assessed the studies.

Main results
The search identified two completed randomised controlled trials (RCTs) and two ongoing trials. The two published RCTs considered outcomes for 3348 mother-baby pairs allocated to either lactate or pH estimation of fetal blood samples when clinically indicated in labour. Overall, the published RCTs were of low or unclear risk of bias. There was a high risk of performance bias, because it would not have been feasible to blind clinicians or participants.

No statistically significant between-group differences were found for neonatal encephalopathy (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.32 to 3.09, one study, 2992 infants) or death. No studies reported neonatal seizures. We had planned to report death with other morbidities, for example, neonatal encephalopathy; however, the data were not available in a format suitable for this, therefore death due to congenital abnormality was considered alone. The three reported neonatal deaths occurred in babies with diaphragmatic hernias (n = 2) or congenital cardiac fibrosis (n = 1). All three babies had been randomised to the pH group and were not acidaemic at birth.

There were no statistically significant differences for any of the pre-specified secondary fetal/neonatal/infant outcomes for which data were available. This included low Apgar score at five minutes (RR 1.13, 95% CI 0.76 to 1.68, two studies, 3319 infants) and admission to neonatal intensive care units (RR 1.02, 95% CI 0.83 to 1.25, one study, 2992 infants), or metabolic acidaemia (RR 0.91, 95% CI 0.60 to 1.36, one study, 2675 infants) considered within the studies, either overall or where data were available for those where fetal blood sampling had occurred within 60 minutes of delivery.

Similar proportions of fetuses underwent additional tests to further evaluate well-being during labour, including scalp pH if in the lactate group or scalp lactate if in the pH group (RR 0.22, 95% CI 0.04 to 1.30, two studies, 3333 infants;Tau² 1.00, I² = 58%). Fetal blood sampling attempts for lactate and pH estimation were successful in 98.7% and 79.4% of procedures respectively in the one study that reported this outcome.

There were no significant between-group differences in mode of birth or operative birth for non-reassuring fetal status, either for all women, or within the group where the fetal blood sample had been taken within 60 minutes of delivery (for example, caesarean section for all enrolled, RR 1.09, 95% CI 0.97 to 1.22, two studies, 3319 women; operative delivery for non-reassuring fetal status for all enrolled RR 1.02, 95% CI 0.93 to 1.11, one study, 2992 women).

Neither study reported on adverse effects of fetal scalp lacerations or maternal anxiety.

Authors' conclusions
When further testing to assess fetal well-being in labour is indicated, fetal scalp blood lactate estimation is more likely to be successfully undertaken than pH estimation. Further studies may consider subgroup analysis by gestational age, the stage of labour and sampling within a prolonged second stage of labour. Additionally, we await the findings from the ongoing studies that compare allocation to no fetal blood sample with sampling for lactate and address longer-term neonatal outcomes, maternal satisfaction with intrapartum fetal monitoring and an economic analysis.
Keyword Randomized Controlled-Trial
Umbilical-Cord Blood
Test Strip Method
Pulse Oximetry
Predictive-Value
Foremost Trial
Cerebral-Palsy
Rate Patterns
Labor
Ph
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online 1 May 2015

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: UQ Centre for Clinical Research Publications
Official 2016 Collection
School of Medicine Publications
School of Nursing, Midwifery and Social Work Publications
 
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Created: Tue, 29 Sep 2015, 01:13:25 EST by Natalie Cowley on behalf of School of Nursing, Midwifery and Social Work