Fetal Monitoring During Labour: A Guide

Image: Pinard horn stethoscope. Credit: AAMI2205, CC BY-SA 3.0, via Wikimedia Commons

During labour, healthcare professionals monitor your baby's heart rate and your contractions to ensure your baby is coping well with the stress of labour. This monitoring provides valuable information about your baby's wellbeing and helps guide decisions about your care. This article explains the different monitoring methods used in UK maternity services, how they work, and what the results mean.

Why Monitor Your Baby During Labour?

Labour places natural stress on your baby as contractions temporarily reduce blood flow to the placenta. Most babies cope well with this process, but monitoring helps identify the small number who may need additional support. The main reasons for fetal monitoring include:

• Detecting potential oxygen deprivation: Identifying early signs that your baby might not be receiving enough oxygen
• Guiding care decisions: Helping healthcare providers determine if labour can safely continue or if intervention is needed
• Reassurance: Providing confirmation that your baby is coping well with labour

The type of monitoring recommended for you will depend on your individual circumstances, including your medical history, pregnancy complications, and how your labour is progressing.

Intermittent Auscultation

Intermittent auscultation is the recommended monitoring method for women with uncomplicated pregnancies who are at low risk of complications. This approach is standard practice in midwife-led units and home births across the UK, and follows the NICE guidelines for intrapartum care.

How it works:

• Your midwife will use a handheld device called a Pinard stethoscope (traditional trumpet-shaped tool) or more commonly, a handheld Doppler ultrasound device
• They listen to your baby's heart rate at regular intervals: every 15 minutes during the first stage of labour and after each contraction or at least every 5 minutes during the pushing phase
• The midwife will count your baby's heartbeats for a full minute, noting the baseline rate and any variations
• They'll also feel your abdomen to monitor contractions and check your baby's position

Advantages:

• Freedom of movement: You can move freely, change positions, use a birth pool, and remain active during labour
• Less technology: Minimal equipment means more natural birth experience
• Reduced intervention: Associated with lower rates of caesarean sections and instrumental deliveries when used appropriately for low-risk women
• Regular personal contact: Your midwife remains closely engaged with you throughout labour

Electronic Fetal Monitoring (EFM)

Electronic fetal monitoring (also called cardiotocography or CTG) provides continuous recording of your baby's heart rate and your contractions. In the UK, this is typically recommended if you have risk factors or if concerns arise during labour.

When EFM is recommended:

According to NICE guidelines, continuous electronic monitoring may be advised if:

• There are maternal risk factors: Such as previous caesarean section, pre-eclampsia, diabetes, or other medical conditions
• There are fetal risk factors: Including growth restriction, prematurity, or reduced movements before labour
• Complications arise during labour: Such as meconium in your waters, bleeding, or the use of oxytocin (syntocinon) to strengthen contractions
• Concerns during intermittent monitoring: If abnormalities are detected during intermittent auscultation

How it works:

• External monitoring (most common):
  • Two sensors are secured to your abdomen with elastic belts
  • One sensor uses ultrasound to detect your baby's heartbeat
  • The other sensor measures the frequency and duration of contractions
  • The information is displayed on a screen and printed on paper as a continuous trace
• Internal monitoring (less common):
  • Used when external monitoring isn't providing clear results
  • A small electrode is attached to your baby's scalp through your cervix (requires your waters to have broken)
  • Provides a more accurate reading of your baby's heart rate
  • A pressure sensor may also be inserted to measure contractions more precisely

Mobility options with EFM:

• Wireless monitoring: Many UK hospitals now offer wireless or telemetry CTG monitoring, allowing you to move around during continuous monitoring
• Birthing ball: If wireless monitoring isn't available, you may still use a birthing ball or adopt various positions near the monitor
• Intermittent monitoring: In some cases, your healthcare team may suggest alternating between periods of monitoring and periods of movement

Understanding CTG Readings

Healthcare professionals are trained to interpret CTG traces by looking at several key features:

Baseline heart rate:

• Normal: Between 110-160 beats per minute
• Tachycardia: Above 160 beats per minute (may indicate infection, dehydration, or fetal distress)
• Bradycardia: Below 110 beats per minute (may indicate oxygen deprivation or other concerns)

Variability:

• Normal: The heart rate naturally varies by 5-25 beats from the baseline (showing good nervous system function)
• Reduced variability: Less than 5 beats variation (may indicate fetal sleep or potential concerns)
• Absent variability: Little or no variation (often concerning, especially when combined with other abnormal patterns)

Accelerations:

• Brief increases in heart rate, usually associated with fetal movement
• Generally a reassuring sign of fetal wellbeing

Decelerations:

• Early decelerations: Mirror contractions and are usually benign
• Variable decelerations: Irregular decreases, often due to cord compression
• Late decelerations: Occur after contractions peak and may indicate reduced oxygen
• Prolonged decelerations: Lasting more than 3 minutes require prompt assessment

Additional Assessment Methods

If there are concerns about your baby's wellbeing based on monitoring, your healthcare team may recommend additional assessment methods:

Fetal blood sampling (FBS):

• A small sample of blood is taken from your baby's scalp during labour to measure pH levels
• Helps to determine if your baby is experiencing significant oxygen deprivation
• May help avoid unnecessary intervention if the CTG is suspicious but not definitely abnormal
• Common in UK obstetric units as recommended by NICE guidelines

Fetal scalp stimulation:

• The doctor gently stimulates your baby's scalp during a vaginal examination
• If your baby responds with an acceleration in heart rate, this is generally reassuring
• A simple test that can sometimes provide quick reassurance

STAN monitoring:

• ST Analysis (STAN) is used in some UK hospitals to provide additional information alongside the CTG
• It analyses changes in the baby's ECG (heart electrical pattern) via a scalp electrode
• May help reduce unnecessary interventions in some cases

How Monitoring Guides Decision-Making

Understanding how monitoring influences care decisions can help you feel more informed during labour:

Normal findings:

• If monitoring shows your baby is coping well, labour will typically continue without intervention
• Your midwife or doctor will continue routine observations

Non-reassuring patterns:

• Initial conservative measures might include:
  • Changing your position
  • Ensuring you're well-hydrated
  • Reducing or stopping oxytocin if being used
  • Providing oxygen in some cases
• Further assessments (like fetal blood sampling) may be offered
• Your healthcare team will explain their concerns and discuss options with you

Abnormal findings:

• If monitoring indicates your baby is in distress, intervention may be recommended
• This might include instrumental delivery (forceps or ventouse) if you're close to giving birth
• A caesarean section may be advised if vaginal birth isn't imminent

Your Rights and Choices

In the UK, principles of informed consent and shared decision-making are fundamental to maternity care:

• Right to information: You should receive clear explanations about recommended monitoring and alternatives
• Right to consent or decline: You can accept or decline monitoring after being informed of the benefits and risks
• Birth plans: Discuss your monitoring preferences in advance with your midwife or doctor
• Questions: Always feel empowered to ask about the reasons for monitoring and what the results show
• Advocacy: Your birth partner can help ensure your preferences are considered during labour

Preparing in Advance

To feel more informed about fetal monitoring before labour begins:

• Discuss at antenatal appointments: Ask your midwife which monitoring approach is likely to be recommended for you
• Attend antenatal classes: NHS and NCT classes typically cover monitoring methods
• Tour the labour ward: Many hospitals offer tours where you can see monitoring equipment
• Include preferences in your birth plan: Note any specific requests about monitoring
• Research your hospital's facilities: Ask if they offer wireless monitoring if mobility is important to you