Conditions · Obstetrics and gynecology
Intrapartum fetal compromise (non-reassuring fetal status) !
Signs during labour, mainly in the baby's heart rate, that the baby may not be getting enough oxygen. Staff act fast to improve it or deliver.
Updated 2026-11-01
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Why it happens
What it is
Evidence during labour, mainly from the fetal heart rate pattern, that the fetus may be hypoxic or acidotic. The term non-reassuring fetal status is preferred over "fetal distress" because the tracing suggests, but does not prove, hypoxia.
Who gets it
Abnormal or indeterminate heart rate patterns occur in a sizeable minority of labours and are a leading indication for emergency caesarean and operative vaginal delivery. Intrapartum hypoxia remains an important cause of stillbirth and neonatal death in Latin America and other middle-income regions.
Causes
- Maternal: hypotension (supine position, epidural), hypoxaemia, fever, severe anaemia
- Uterine: tachysystole (too many contractions, often with oxytocin), uterine rupture
- Placental: insufficiency (preeclampsia, growth restriction, post-term), abruption
- Umbilical cord: compression, prolapse, true knot
- Fetal: infection, anaemia, arrhythmia
Risk factors
- Preeclampsia and chronic hypertension
- Fetal growth restriction and post-term pregnancy
- Oligohydramnios and meconium-stained fluid
- Oxytocin induction or augmentation
- Chorioamnionitis and maternal fever
- Previous caesarean (risk of rupture)
Pathophysiology
Each contraction briefly reduces blood flow through the uterine arteries to the placenta. A healthy fetus tolerates this, but if reserve is low or flow is cut further, oxygen falls. Cord compression triggers abrupt variable decelerations via baroreceptors, while uteroplacental insufficiency produces late decelerations via chemoreceptors. Prolonged hypoxia leads to anaerobic metabolism, metabolic acidosis, loss of heart rate variability and, eventually, organ and brain injury.
Classification
- Category I (normal): baseline 110–160 bpm, moderate variability, no late or variable decelerations
- Category II (indeterminate): any pattern not in category I or III; needs close surveillance and corrective measures
- Category III (abnormal): absent variability with recurrent late or variable decelerations or bradycardia, or a sinusoidal pattern
- Decelerations: early (head compression, benign), variable (cord compression), late (uteroplacental insufficiency)
Symptoms and signs
- Fetal tachycardia or bradycardia outside the normal baseline
- Reduced or absent baseline variability
- Recurrent late decelerations after the contraction peak
- Recurrent or deep variable decelerations
- Thick meconium-stained amniotic fluid
Diagnosis
- Clinical
- Interpretation of the fetal heart rate tracing in relation to contractions (baseline, variability, accelerations, decelerations), in the context of maternal condition, labour progress and risk factors. Intermittent auscultation is used in low-risk labour and continuous cardiotocography when risk is higher.
- Tests
- Fetal scalp stimulation (an acceleration in response is reassuring); fetal scalp blood sampling for pH or lactate where available; umbilical cord blood gases after birth to confirm acidosis.
- Imaging
- Bedside ultrasound to check fetal heart activity, position and amniotic fluid when needed.
Differential diagnosis
- Maternal heart rate recorded instead of the fetal heart
- Fetal sleep cycle (temporarily reduced variability)
- Effects of maternal medicines such as opioids
- Fetal arrhythmia
- Benign early decelerations from head compression
Goal of treatment
Identify and correct the cause through intrauterine resuscitation and, if the tracing does not improve or is category III, deliver quickly by the safest route.
Treatment
- Acute
- Intrauterine resuscitation: turn the mother to her left side, give an intravenous fluid bolus, treat hypotension and give oxygen if the mother is hypoxaemic.
- Acute
- Stop or reduce oxytocin; give a tocolytic for tachysystole.
- Procedure
- Vaginal examination to exclude cord prolapse or rapid descent; amnioinfusion for recurrent variable decelerations in selected settings.
- Surgical
- Expedited delivery by operative vaginal birth or caesarean if the pattern persists or is category III.
- Follow-up
- Nursing: continuous monitoring, documentation and escalation of the tracing, maternal position and vital signs; neonatal resuscitation team at delivery and cord gases.
Complications
- Metabolic acidosis at birth
- Hypoxic-ischaemic encephalopathy, seizures, cerebral palsy
- Meconium aspiration syndrome
- Stillbirth or neonatal death
- Higher rates of operative delivery for the mother
Prognosis
Most babies with abnormal tracings are born healthy, because the tracing has high sensitivity but low specificity for acidosis. Prolonged, uncorrected hypoxia carries a risk of permanent brain injury or death.
Prevention
- Appropriate fetal monitoring according to risk
- Careful oxytocin use and avoiding tachysystole
- Avoiding the supine position and treating maternal hypotension
- Antenatal detection of growth restriction and preeclampsia
Test yourself
Think of the answer, then tap the question to see it.
What do late decelerations indicate?
Uteroplacental insufficiency with possible fetal hypoxaemia and acidosis.
What causes variable decelerations?
Umbilical cord compression.
What do early decelerations reflect?
Fetal head compression; they are benign.
What is the first nursing action for late decelerations during oxytocin infusion?
Stop the oxytocin, turn the mother on her left side, give IV fluids and notify the provider.
What is the normal fetal heart rate baseline?
110 to 160 beats per minute with moderate variability.
Related conditions
- Umbilical cord prolapse
- Placental abruption
- Uterine rupture
- Fetal growth restriction
- Chorioamnionitis (intra-amniotic infection)
- Preeclampsia
- Perinatal asphyxia and hypoxic-ischaemic encephalopathy
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Fetal Monitoring During Labor and Delivery (MSD Manual Professional Edition, 2024); Non-reassuring fetal status: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data (Vaccine (Brighton Collaboration), via PubMed Central, 2016).
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