Fetal distress in labour: heart rate monitoring and what happens

The NHS describes fetal distress as a situation in which the baby's heart rate gets faster or slower before birth, which can mean the baby is not getting enough oxygen and may need to be delivered quickly to avoid birth injuries or stillbirth. NICE uses terms such as fetal compromise and avoids confusing labels when classifying traces. The Rotherham NHS trust says that during contractions blood does not flow as easily through the placenta so the baby may receive less oxygen for a while; this is normal and most babies cope well.

The Rotherham trust is also clear that you can choose not to have your baby's heartbeat monitored, but that this would mean the team could not tell whether the baby was coping, and that difficulties left untreated could have serious effects.

Two methods are described by NICE and by the George Eliot Hospital and Rotherham NHS trusts. Intermittent auscultation uses a handheld Pinard stethoscope or Doppler to listen straight after a contraction for at least a minute. NICE says this should be done at least every 15 minutes in the established first stage and at least every 5 minutes in the second stage. It is offered when you are at low risk, allows you to move freely, and is the only method available if you give birth at home. Continuous monitoring uses a cardiotocograph (CTG): two belts hold sensors on the abdomen, one detecting the baby's heartbeat and one the contractions.

If the sensors cannot pick up a good trace, because of position or a higher BMI for example, the Rotherham trust says a fetal scalp electrode may be suggested. It is a small clip on the baby's scalp, inserted during a vaginal examination, which can cause a small scratch and, uncommonly, other problems. Some trusts have wireless, waterproof monitors that let you keep moving or use a birth pool.

NICE advises assessing antenatal risk factors at the onset of labour to decide which method to start with. It says if there are no risk factors for fetal compromise, continuous CTG carries a risk of increased interventions compared with intermittent auscultation that may outweigh the benefits. NICE lists antenatal risk factors for which continuous CTG is offered, such as a previous caesarean or other full-thickness uterine scar, hypertension needing medication, any vaginal blood loss other than a show, suspected infection or sepsis, diabetes needing treatment, a baby who is breech, transverse or oblique, poor growth, pregnancy beyond 42 weeks, too much or too little amniotic fluid, and reduced movements in the previous 24 hours. New risk factors in labour that prompt it include contractions lasting longer than 2 minutes or five or more in 10 minutes, meconium and a fever (38 degrees or above on one reading).

The Rotherham trust lists reasons the team may advise continuous monitoring from the start: diabetes, raised blood pressure, heart or kidney problems, being under 37 or over 42 weeks, vaginal bleeding, an epidural, twins, induced or accelerated labour, a previous caesarean, concerns about growth, reduced movements, a breech baby, waters broken for more than 24 hours or not clear. Meconium, the baby's first stool in the fluid, is described by NICE as something that can indicate possible fetal compromise and should trigger a full risk assessment and discussion of CTG.

The Rotherham trust explains that the trace shows the baseline heart rate, variability, accelerations and decelerations, and how often and how long contractions last. NICE scores each of four features (contractions, baseline, variability, decelerations) as white, amber or red. A trace is normal when all four are white, suspicious when one is amber, and pathological when one is red or two or more are amber.

The Rotherham trust describes an hourly "fresh eyes" review in which another midwife or doctor checks the trace, how you are coping and other signs. The George Eliot Hospital trust notes a limitation: it can be hard to interpret the pattern, and it does not always reflect accurately how well the baby is coping, which may lead to extra intervention.

For a suspicious trace, NICE says to carry out a full risk assessment, including your own observations, and to try conservative measures based on the likely cause. For a pathological trace, urgent review by an obstetrician and senior midwife is advised, excluding emergencies such as cord prolapse, suspected placental abruption or suspected uterine rupture. If the trace is still pathological after conservative measures, a further urgent review is needed and birth may be expedited.

Conservative measures named by NICE include changing position (and avoiding lying flat), moving about, and treating the likely cause. The Rotherham trust describes changing position, intravenous fluids, an antacid, paracetamol or antibiotics, sometimes terbutaline to reduce contractions, and a vaginal examination with fetal scalp stimulation, whose response gives information on how well the baby is coping. NICE advises against facial oxygen for the mother as part of these measures because it may harm the baby.

If the baby does not seem to be coping, the team may recommend a quicker birth: ventouse, forceps or caesarean, depending on how fast things need to move, as Tommy's and the Rotherham trust explain. They should explain why and ask for your consent. The NHS notes an episiotomy may be recommended in these circumstances.

Your baby's movements are one way to check they are well before labour. Tommy's says you should feel movements right up to and during labour, and to contact your midwife or hospital straight away if movements slow, stop or change. In labour, tell your midwife about any bleeding, a change in the colour of your waters, new constant pain or a fever. Maternity policies and monitoring equipment vary between trusts and the four UK nations.