What is the most effective way to listen intermittently to the baby’s heart in labour to improve the baby’s well-being?

What is the issue?

One method of monitoring a baby's well-being is to listen to the fetal heart rate and its pattern intermittently during labour (intermittent auscultation). There are several ways that the baby's heart rate can be measured. Some tools for listening to the baby's heart are made from wood, plastic or aluminium (Pinard, Laennec and fetoscope), and there are also electronic tools of varying sophistication, including hand-held (battery or wind-up operated) Doppler ultrasound (Doppler) and cardiotocogram (CTG), which is sometimes referred to as electronic fetal monitoring (EFM).

Why is this important?

The aim of monitoring is so that babies in difficulty can be accurately identified and interventions (such as caesarean section or instrumental vaginal birth) can be used to improve outcomes for the baby.

What evidence did we find?

We wanted to look at which types listening tools and timing for intermittent auscultation are most effective. We considered hand held listening devices, e.g. hand-held Dopplers and various Pinard stethoscopes. We searched for studies (19 September 2016) and found three randomised controlled studies from Africa, involving 6241 women in established labour. Data from one of the studies were inconsistent and we were unable to include them in the results. This means 3242 women and their babies were included in the analyses. The results of the studies may have been biased as it was not possible to blind women and staff, and the overall the quality of the evidence was judged to be of moderate to very low quality.

One study compared intermittent EFM with routine Pinard and showed no clear difference between groups in low baby Apgar scores at five minutes after the birth (very low-quality evidence) or in perinatal mortality (low-quality evidence) although neonatal seizures were reduced in the EFM group (low-quality evidence). Other important infant outcomes (such as cerebral palsy) were not reported. Women who had intermittent EFM had higher rates of caesarean section for fetal distress (moderate-quality evidence), but there was no clear difference between groups in instrumental vaginal births (low-quality evidence). Other important outcomes for women were not reported (maternal mortality, analgesia in labour, mobility or restriction during labour, and postnatal depression).

Two studies compared Doppler ultrasonography with routine Pinard. There was no clear difference between groups in low Apgar scores at five minutes after birth (very low-quality evidence) or for perinatal mortality (very low-quality evidence), or neonatal seizures (very low-quality evidence). Other important infant outcomes were not reported. Only one study reported outcomes for women. Those that had Doppler ultrasonography had higher rates of caesarean section for fetal distress compared with routine Pinard (moderate-quality evidence). There was no clear difference in instrumental vaginal births between groups (low-quality evidence). Other maternal outcomes were not reported.

One trial compared intensive Pinard (a research midwife in a one-to-one care situation) with routine Pinard (the midwife may have been caring for more than one woman in labour). There was no clear difference between groups in low Apgar scores (very low-quality evidence), perinatal mortality (very low-quality evidence), or neonatal seizures (very low-quality evidence)). Other infant outcomes were not reported. For women, there were no clear differences between groups for caesarean section or instrumental delivery (both low-quality evidence)) Other outcomes were not reported.

What does this mean?

As intermittent EFM and Doppler were associated with higher rates of caesarean sections compared with routine Pinard monitoring, women, health practitioners and policy makers need to consider these results in the absence of evidence of short- and long-term benefits for the mother or baby.

Large high-quality studies comparing different monitoring tools and timing for intermittent auscultation are needed. Studies should assess both short- and long-term health outcomes, and should collect information on women's views.

Authors' conclusions: 

Using a hand-held (battery and wind-up) Doppler and intermittent CTG with an abdominal transducer without paper tracing for IA in labour was associated with an increase in caesarean sections due to fetal distress. There was no clear difference in neonatal outcomes (low Apgar scores at five minutes after birth, neonatal seizures or perinatal mortality). Long-term outcomes for the baby (including neurodevelopmental disability and cerebral palsy) were not reported. The quality of the evidence was assessed as moderate to very low and several important outcomes were not reported which means that uncertainty remains regarding the use of IA of FHR in labour.

As intermittent CTG and Doppler were associated with higher rates of caesarean sections compared with routine Pinard monitoring, women, health practitioners and policy makers need to consider these results in the absence of evidence of short- and long-term benefits for the mother or baby.

Large high-quality randomised trials, particularly in low-income settings, are needed. Trials should assess both short- and long-term health outcomes, comparing different monitoring tools and timing for IA.

Read the full abstract...
Background: 

The goal of fetal monitoring in labour is the early detection of a hypoxic baby. There are a variety of tools and methods available for intermittent auscultation (IA) of the fetal heart rate (FHR). Low- and middle-income countries usually have only access to a Pinard/Laënnec or the use of a hand-held Doppler device. Currently, there is no robust evidence to guide clinical practice on the most effective IA tool to use, timing intervals and length of listening to the fetal heart for women during established labour.

Objectives: 

To evaluate the effectiveness of different tools for IA of the fetal heart rate during labour including frequency and duration of auscultation.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (19 September 2016), contacted experts and searched reference lists of retrieved articles.

Selection criteria: 

All published and unpublished randomised controlled trials (RCTs) or cluster-RCTs comparing different tools and methods used for intermittent fetal auscultation during labour for fetal and maternal well-being. Quasi-RCTs, and cross-over designs were not eligible for inclusion.

Data collection and analysis: 

All review authors independently assessed eligibility, extracted data and assessed risk of bias for each trial. Data were checked for accuracy.

Main results: 

We included three studies (6241 women and 6241 babies), but only two studies are included in the meta-analyses (3242 women and 3242 babies). Both were judged as high risk for performance bias due to the inability to blind the participants and healthcare providers to the interventions. Evidence was graded as moderate to very low quality; the main reasons for downgrading were study design limitations and imprecision of effect estimates.

Intermittent Electronic Fetal Monitoring (EFM) using Cardiotocography (CTG) with routine Pinard (one trial)

There was no clear difference between groups in low Apgar scores at five minutes (reported as < six at five minutes after birth) (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.24 to 1.83, 633 babies, very low-quality evidence). There were no clear differences for perinatal mortality (RR 0.88, 95% CI 0.34 to 2.25; 633 infants, very low-quality evidence). Neonatal seizures were reduced in the EFM group (RR 0.05, 95% CI 0.00 to 0.89; 633 infants, very low-quality evidence). Other important infant outcomes were not reported: mortality or serious morbidity (composite outcome), cerebral palsy or neurosensory disability. For maternal outcomes, women allocated to intermittent electronic fetal monitoring (EFM) (CTG) had higher rates of caesarean section for fetal distress (RR 2.92, 95% CI 1.78 to 4.80, 633 women, moderate-quality evidence) compared with women allocated to routine Pinard. There was no clear difference between groups in instrumental vaginal births (RR 1.46, 95% CI 0.86 to 2.49, low-quality evidence). Other outcomes were not reported (maternal mortality, instrumental vaginal birth for fetal distress and or acidosis, analgesia in labour, mobility or restriction during labour, and postnatal depression).

Doppler ultrasonography with routine Pinard (two trials)

There was no clear difference between groups in Apgar scores < seven at five minutes after birth (reported as < six in one of the trials) (average RR 0.76, 95% CI 0.20 to 2.87; two trials, 2598 babies, I2 = 72%, very low-quality evidence); there was high heterogeneity for this outcome. There was no clear difference between groups for perinatal mortality (RR 0.69, 95% CI 0.09 to 5.40; 2597 infants, two studies, very low-quality evidence), or neonatal seizures (RR 0.05, 95% CI 0.00 to 0.91; 627 infants, one study, very low-quality evidence). Other important infant outcomes were not reported (cord blood acidosis, composite of mortality and serious morbidity, cerebral palsy, neurosensory disability). Only one study reported maternal outcomes. Women allocated to Doppler ultrasonography had higher rates of caesarean section for fetal distress compared with those allocated to routine Pinard (RR 2.71, 95% CI 1.64 to 4.48, 627 women, moderate-quality evidence). There was no clear difference in instrumental vaginal births between groups (RR 1.35, 95% CI 0.78 to 2.32, 627 women, low-quality evidence). Other maternal outcomes were not reported.

Intensive Pinard versus routine Pinard (one trial)

One trial compared intensive Pinard (a research midwife following the protocol in a one-to-one care situation) with routine Pinard (as per protocol but midwife may be caring for more than one woman in labour). There was no clear difference between groups in low Apgar score (reported as < six this trial) (RR 0.90, 95% CI 0.35 to 2.31, 625 babies, very low-quality evidence). There were also no clear differences identified for perinatal mortality (RR 0.56, 95% CI 0.19 to 1.67; 625 infants, very low-quality evidence), or neonatal seizures (RR 0.68, 95% CI 0.24 to 1.88, 625 infants, very low-quality evidence)). Other infant outcomes were not reported. For maternal outcomes, there were no clear differences between groups for caesarean section or instrumental delivery (RR 0.70, 95% CI 0.35 to 1.38, and RR 1.21, 95% CI 0.69 to 2.11, respectively, 625 women, both low-quality evidence)) Other outcomes were not reported.

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