Intermittent auscultation (IA) is the auscultation of the fetal heart at intermittent intervals, using a pinards stethoscope or a hand-held doppler device. Midwives have traditionally monitored according to the stage of labour and increased the frequency of auscultation when the woman is in established, advanced labour. Unfortunately, there have been no trials to compare the more flexible and individualised time intervals for monitoring the fetal heart rate (FHR), relative to the stage of labour and the degree of risk. In the absence of any randomised controlled trials, National Institute for Health and Clinical Excellence (NICE) (2007) has made recommendations for IA based only on medical expert committee opinion, recommending auscultation after a contraction for 1 minute:

• Every 15 minutes in the first stage of labour
  
• Every 5 minutes in the second stage of labour

Beech Lawrence (2001) and Spiby (2001) suggest that frequent IA may be as restrictive as continuous EFM.

Using a pinards/hand-held doppler

Effective use of a pinards requires a precise awareness of the baby’s position, and indeed it can be used to confirm position. One benefit of the pinards is that it will only pick up the fetal, rather than the maternal heart rate. A pinards can be used throughout labour. Women may find the pressure required for good pinards auscultation uncomfortable. A hand-held doppler device can be placed more lightly on the abdomen and also allows others to hear the fetal heart. A water-resistant device can be used in baths/birthing pools. Some midwives/women may prefer the simplicity of the pinards and are aware that while the use of doppler ultrasound appears to be safe, it has never been proved unequivocally to be so.

To use a pinards, palpate to ascertain the fetal position and place the bell end over the baby’s torso. Then press the ear on to the flat end to secure it and let go of the pinards, carefully listen for a muffled thudding, the same sound as putting an ear directly over someone’s chest to hear their heart. Midwives can purchase their own wooden pinards from the Association of Radical Midwives (ARM) (listed in the ‘Useful contacts’ section at the end of this chapter).

If there are any factors of concern regarding the FHR the assessment of variability becomes important. The FHR should vary at least five beats from the baseline rate over a period of 1 minute. However, it is particularly difficult to assess by audibility alone. A hand-held doppler that displays the FHR is useful, as it shows variations of the heart rate.

If there is any deviation from the norm, such as decelerations, bradycardia or tachycardia, then a cardiotocography (CTG) should be commenced, or, if at home, consider transfer to hospital for a CTG. However, FH decelerations often occur in the second stage, and if delivery is imminent a CTG may be impractical and pointless. Hindley et al. (2006) explain some midwives find IA difficult to implement because their maternity units promote active management of labour over more conservative approaches to childbirth. Many units still have their own fetal monitoring guidelines (Hindley et al., 2005) which may not always conform to NICE guidelines.

‘EFM was introduced with the aim of reducing perinatal mortality and cerebral palsy. This reduction has not been demonstrated in the systematic reviews of randomised controlled trials (RCTs). However an increase in maternal intervention rates has been shown’ (NICE, 2007).

Despite the lack of evidence to support EFM, even for women deemed ‘high-risk’, NICE (2007) continues to recommend its routine use for any woman with a ‘risk’ factor. For a variety of complex reasons, EFM technology has become part of the hospitalbirth culture (Walsh, 2001). As part of this culture, hospital doctors and midwives rely heavily on this form of monitoring as part of their skill base, even if evidence suggests their confidence may be misplaced. It may be difficult for many clinicians to re-skill themselves physically and psychologically and to, therefore, avoid coercing women into accepting EFM. Hindley et al. (2006) found that although midwives may state that it is theoretically preferable to use IA, many continue to be reliant on EFM for fear of missing a pathological FH feature. It was also found that EFM continues to be used on busy shifts when one-to-one care is not available.

Units using EFM should have fetal blood sampling (FBS) available before a caesarean section (CS) is performed. This technique allows fetal capillary blood to be tested for its pH values, leading to an indication of action to be taken (for more information see the Appendix and ‘Fetal blood tests’ in Chapter 23). FBS can, in theory, (a) confirm the need for a CS or (b) reassure and avoid an unnecessary CS which otherwise would have been carried out based on CTG evidence alone. However, Cochrane review found no evidence of higher CS rates when FBS was not available (Alfirevic et al., 2006) and NICE (2007) reports increased instrumental delivery but no difference in outcomes.

NICE (2007) recommends the following:

• The ‘admission trace’ should be abandoned for low-risk women: they should be offered intermittent auscultation.
  
• EFM should be offered to ‘high-risk’ cases.

Indications for continuous EFM can be seen in the Appendix.

NICE also suggests EFM for:

• Meconium-stained liquor

 Light staining: consider EFM based on assessment of other risks, e.g. stage/ progress of labour

 Significant staining, e.g. thick/tenacious dark green or black staining, or lumps of meconium: advise continuous EFM

• Fresh bleeding in labour
  
• Oxytocin for augmentation
  
• Maternal pyrexia: 38°C once or 37.5°C twice 2 hours apart

To perform a CTG:

• Explain to the mother why continuous CTG is being offered. Consent must be obtained.
  
• Record the indication in the notes and on the CTG.
  
• Label the CTG with date, the mother’s name, hospital number and maternal pulse to differentiate it from the FHR.
  
• The date and time should be set correctly, and the paper speed should be at 1 cm/min (in the UK).
  
• Palpate for position and presentation.
  
• Auscultate using a pinards prior to positioning the FH monitor, as the ultrasound can ‘double up’ the maternal pulse and show a false FHR.
  
• Attach the toco (pressure sensitive) contraction monitor around the top of the uterus and the FH monitor over the fetal heart area. Secure with belts.
  
• Explain simply to the parents the range of the fetal heart and the contraction line. Explain that any ‘loss of contact’ does not mean that the baby’s heartbeat has stopped.
  
• Undo monitor belts and encourage periodic mobilisation, if possible, to reduce discomfort and complications caused by restricted mobility.
  
• Consider any external factors that may cause a change in the FHR, e.g. lying flat for an examination, vomiting or pethidine, and note them on the CTG. Usually, a change of position to left lateral or sitting more upright will resolve any anomalies. Lying flat can cause aortocaval compression, which is the compression of the inferior vena cava and the aorta by the gravid uterus, often producing maternal hypotension and fetal hypoxia.
  
• Anyone asked to review the trace should note their findings on the trace and in more detail in the maternal notes, along with the date, time and signature.
  
• Following the birth, the midwife should sign the CTG and write the time and type of birth.
  
• The CTG should be filed securely in the maternity record. CNST (2006) recommend re-sealable hole-punched envelopes.
  
• If there is a poor outcome, all CTG traces should be copied as the original is likely to deteriorate in quality and records may need to be examined years after the event.
  
• Altaf et al. (2006) found that a lack of ownership relating to the cleaning and maintenance of CTG machines was a considerable cause of frustration and time wastage for staff.

A fetal scalp electrode (FSE) is an accurate but invasive form of monitoring the FHR. Once frequently used, such monitoring is now generally only used where there is significant concern about the FHR with poor contact from the external CTG. It can occasionally cause scarring and/or neonatal infection.

The FSE should not be applied if:

• The woman’s consent is not obtained (most women do not like the idea of a clip piercing their baby’s skin).
  
• The baby is <34 weeks gestation or has a bleeding disorder, e.g. haemophilia.
  
• There is a non-cephalic or non-vertex presentation.
  
• The woman has an infection, pyrexia, human immunodeficiency virus, hepatitis or any sexually transmitted disease, or the woman is in a high-risk group for these conditions (such as an intravenous drug user).