The addition of fetal scalp blood lactate measurement as an adjunct to cardiotocography to reduce caesarean sections during labour: The Flamingo randomised controlled trial

Abstract

Background Fetal scalp blood sampling for lactate measurement (FBSLM) is sometimes used to assist in identification of the need for expedited birth in the presence of an abnormal cardiotocograph (CTG). However, there is no randomised controlled trial evidence to support this. Aim To determine whether adding FBSLM reduces the risk of birth by emergency caesarean section in labours complicated by an abnormal CTG, compared with CTG without FBS. Material and Methods Labouring women at a tertiary maternity hospital in Melbourne, Australia with a singleton, cephalic presentation, at ≥37 weeks gestation with an abnormal CTG pattern were randomised to the intervention (n = 61), with intermittent FBSLM in addition to CTG monitoring, or control (CTG without FBS, n = 62). The primary outcome was rate of birth by caesarean section. Secondary outcomes included overall operative birth and fetal and neonatal safety endpoints. Trial registration: ACTRN12611000172909. Results The smaller than anticipated sample was unable to demonstrate an effect from adding FBSLM to CTG monitoring on birth by caesarean section vs monitoring by CTG without FBS (25/61 and 28/62 respectively, P = 0.64, risk ratio 0.91, 95% confidence intervals 0.60–1.36). One newborn infant in the CTG group met the criteria for the composite neonatal outcome of death or serious outcome, neonatal encephalopathy, five‐minute Apgar score < 4, neonatal resuscitation, admission to neonatal intensive care unit for 96 h or more. Conclusion We were unable to provide robust evidence of the effectiveness of FBSLM to improve the specificity of the CTG in the assessment of fetal wellbeing.

Proposed cutoff for fetal scalp blood lactate in intrapartum fetal surveillance based on neonatal outcomes: a large prospective observational study

“…The randomised controlled study by Haverkamp et al. and the recent Flamingo trial were both underpowered to show any reductions in interventions by the use of FBS 47,48 …”

“…The randomised controlled study by Haverkamp et al and the recent Flamingo trial were both underpowered to show any reductions in interventions by the use of FBS. 47,48 The strengths of this study are primarily, the large sample size, which enabled cutoffs to be derived from a wide range of lactate values, some also obtained close to birth, and that FBS and umbilical cord blood sampling are well established routines in the included labour wards.…”

Intrapartum fetal heart rate monitoring: Rationalise, refine or replace?

“…However, pH has largely been superseded by bedside lactate monitoring, a cheaper, faster option with a lower failure rate due to the smaller blood sample required. 14 The value of scalp lactate is in the strong negative predictive value of the test. 15 However, there is insufficient evidence that scalp blood sampling decreases intervention rates or improves specificity of fetal monitoring.…”

“…15 However, there is insufficient evidence that scalp blood sampling decreases intervention rates or improves specificity of fetal monitoring. 14 Clinical guidelines seek to unify procedures to improve maternal and fetal outcomes. With many variations internationally, others like Brown and colleagues have suggested the development of an international fetal monitoring guideline would improve specificity and decrease unnecessary intervention.…”

Ingen grunn til endring av anbefalinger om fosterovervåkning

“…For disse målere er det foreslå en grense for intervensjon for laktat verdier ≥ 5,2 mmol/l, som en balanse mellom å oppnå best sensitivitet, spesifisitet og negativ sannsynlighet for neonatale utfall (4). Forfa erne nevner Flamingostudien, en randomisert kontrollert studie om bruk av laktatmåling i fødsel, uten å kunne vise en reduksjon i intervensjon med keisersni (5). Studien ble dessverre avbrudd e er 121 av 600 planlagte deltakere og har dermed ikke Ingen grunn til endring av anbefalinger om fosterovervåkning | Tidsskrift for Den norske legeforening…”