A CTG (cardiotocograph) records your baby's heart rate with one belt and the tightening of your womb with another, usually for 20 to 40 minutes. Done before labour it is called a non-stress test in the US. A normal trace has a baseline of 110–160 beats per minute (bpm), variability of 5–25 bpm, accelerations, and no repeated decelerations.
This page explains what each of those words means on your printout, when a non-stress test counts as reactive, why the test sometimes runs much longer than planned and what the Fischer score on some reports adds up. It also has a decoder for the numbers on your report and a comparison of when different countries offer the test.
The short answer: FIGO calls a CTG normal when the baseline is 110–160 bpm, variability is 5–25 bpm and there are no repetitive decelerations. Before labour, a non-stress test is reactive when the heart rate rises by at least 15 bpm for 15 seconds at least 2 times within 20 minutes (10 bpm for 10 seconds before 32 weeks). A sleeping baby can make a healthy trace look flat, so the test is often extended to 40 minutes.
What a CTG records
You lie back or on your side while a midwife or nurse straps two flat discs to your bump. One sits where the baby's heartbeat is clearest and picks up the heart rate by Doppler ultrasound. The other is a pressure sensor (a tocodynamometer) near the top of the womb that registers tightenings. The machine prints both as lines on a paper strip or a screen: heart rate on top, contractions below. German guidance recommends lying tilted to the left late in pregnancy, so the womb does not press on the large vein behind it and make you feel faint.
The heart-rate line is what the test is about. The contraction line shows how often your womb tightens, including Braxton Hicks you may not feel. FIGO points out that this belt shows reliably how often contractions come, not how strong they are.
How to read a CTG: the four features
Whoever reads your trace looks at four features of the heart-rate line, in this order. FIGO's 2015 consensus, which the German guideline and many others follow, then sorts the whole trace into normal, suspicious or pathological.
| Feature | Normal | Suspicious | Pathological |
|---|---|---|---|
| Baseline | 110–160 bpm | Lacks at least one normal feature, but has no pathological one | Below 100 bpm |
| Variability | 5–25 bpm | Below 5 bpm for more than 50 min, above 25 bpm for more than 30 min, or a sinusoidal pattern for more than 30 min | |
| Decelerations | No repetitive decelerations | Repetitive late or prolonged decelerations for more than 30 min (20 min with reduced variability), or one prolonged deceleration of more than 5 min | |
| What it suggests | No oxygen shortage | Low probability of oxygen shortage | High probability of oxygen shortage |
Source: FIGO consensus guidelines on intrapartum fetal monitoring, cardiotocography (Ayres-de-Campos et al. 2015), Table 1. Decelerations count as repetitive when they come with more than 50% of contractions. Accelerations are not part of the classification.
Baseline
The baseline is the average heart rate over about ten minutes, leaving out the rises and dips. A normal baseline is 110 to 160 bpm. Babies tend to sit near the top of that range earlier in pregnancy and nearer the bottom after the due date, which is why a baseline of 100 to 109 bpm can be normal after 40 weeks. FIGO calls a baseline above 160 bpm for more than 10 minutes a tachycardia and names a fever in the mother as its most frequent cause. The fetal heart rate by week page shows how the rate changes across pregnancy.
Variability
Variability is the small, constant wobble of the line around the baseline, measured as the gap between the highest and lowest point in each minute. A healthy nervous system keeps adjusting the heart rate, so a normal wobble of 5 to 25 bpm is one of the most reassuring things on the strip. During deep sleep variability sits at the lower end of normal, and some medicines, such as opioid painkillers, flatten it too.
Accelerations
Accelerations are short rises of more than 15 bpm lasting more than 15 seconds, usually when the baby moves. Before 32 weeks they are smaller, and 10 bpm for 10 seconds counts. NICE says accelerations are generally a sign that the baby is healthy, while their absence on an otherwise normal trace does not mean the baby is short of oxygen. That is why FIGO leaves them out of the classification but they decide the result of a non-stress test.
Decelerations
Decelerations are dips of more than 15 bpm below the baseline lasting more than 15 seconds. Their shape and timing matter more than their depth:
- Early decelerations are shallow, mirror each contraction and come from pressure on the baby's head in labour. They are benign.
- Variable decelerations drop and recover quickly, in a V shape, and are the commonest kind in labour. They usually come from brief squeezing of the umbilical cord. NICE asks for closer review when they last more than 60 seconds, recover slowly or come with other changes.
- Late decelerations start after a contraction has peaked and recover only after it ends, in a U shape. They suggest the baby is reacting to a shortage of oxygen and always need a doctor's review.
- Prolonged decelerations last more than 3 minutes. One that goes past 5 minutes is pathological under FIGO and is acted on at once.
How NICE reads the same trace
In the UK, NICE NG229 rates each feature white, amber or red. A baseline of 110–160 bpm is white, 100–109 bpm or a rise of 20 bpm since labour began is amber, and below 100 or above 160 bpm is red. Variability under 5 bpm is amber for 30–50 minutes and red after that, and a single deceleration of 3 minutes or more is red. The trace is normal when every feature is white, suspicious with one amber feature, and pathological with one red or two amber features.
Reactive and non-reactive non-stress tests
Before labour, the question is simpler: does the heart rate speed up when the baby moves? ACOG calls the test reactive when at least 2 accelerations appear within 20 minutes, and describes that as reassuring for now. A non-reactive test has too few accelerations after 40 minutes.
A non-reactive result most often means the baby was asleep. FIGO notes that after 32 to 34 weeks a baby's deep sleep can last up to 50 minutes, with very few accelerations and variability at the low end of normal. The midwife may extend the recording, or hold a small buzzer to your bump to wake the baby. A Cochrane review of 12 trials with 6,822 women found this sound and vibration stimulus cut non-reactive results and shortened the test. If the trace still does not react, ACOG lists a biophysical profile among the next tests: a scan that adds the baby's breathing, movements, muscle tone and fluid to the heart-rate trace.
CTG report decoder
Fill in whatever your report gives. The decoder reads each number against the published definition of that one feature and tells you what the guidelines say about it. It does not classify your whole trace: a doctor or midwife does that by looking at the line itself, which no set of numbers captures.
What the guidelines say about each number
Whatever the numbers: if your baby is moving less than usual, call your maternity unit straight away, even if your last CTG was normal.
The Fischer score (CTG points)
Reports printed in Germany, Ukraine, Russia and Poland may add a score out of 10. It comes from Fischer and colleagues, who in 1976 proposed scoring a trace taken before labour the way an Apgar score rates a newborn: five features, each worth 0, 1 or 2 points. A total of 8 to 10 is reassuring, 5 to 7 is borderline and calls for a repeat or longer recording, and 4 or less is a warning sign that needs a doctor's review.
The five features are the baseline heart rate, the amplitude of the variability, how often the trace swings across its baseline, accelerations and decelerations. The limits that earn 0, 1 or 2 points for each feature differ between textbooks: German references and Russian-language ones print different cut-offs, and we could not check either against Fischer's original 1976 table. So this page gives no points-per-feature table. If your report lists points for each feature, the person who scored it can tell you which version they used. Every version agrees that 8 to 10 points is reassuring.
German guidelines have moved on: the 2023 S3 guideline tells doctors to read a CTG with the FIGO classification, which the German S1 guideline calls the only score with wide agreement. If your report has both a Fischer score and a FIGO category, the FIGO category is the one your doctor will act on.
Computerised CTG and the Dawes–Redman criteria
Many units, especially in the UK, let software read the antenatal trace using the Dawes–Redman criteria. The program checks the trace against ten criteria. Once all are met, it prints "criteria met" and the recording can stop, often well before the planned time. If they are still not met after 60 minutes, it prints "criteria not met" and advises the staff to ask for an expert opinion. "Not met" means a person needs to look, not that the baby is unwell. These reports often add a short-term variation (STV) in milliseconds, which the software works out from the intervals between beats.
How the test is done and how long it takes
A non-stress test takes at least 20 minutes, and German guidance sets 30 minutes as the usual minimum. Plan for up to an hour: if your baby sleeps, the recording continues until the baby wakes. Nothing is injected and nothing is done to cause contractions, which is where the name non-stress comes from. Go to the toilet first, eat as you normally would and bring something to do.
A sweet drink before the test is a popular tip, but a Cochrane review of 2 trials with 708 women found that glucose did not reduce non-reactive results. In labour, NICE recommends continuous CTG for women with risk factors such as a previous caesarean, high blood pressure that needs medicine, type 1 or type 2 diabetes, gestational diabetes treated with medicine, bleeding or signs of infection. Otherwise the midwife listens to the heartbeat at intervals, and you can time your contractions with our contraction timer before you go in.
When is a CTG offered?
The answer depends on the country, because guidelines disagree on whether a healthy pregnancy needs one:
- WHO: routine CTG during pregnancy is not recommended to improve outcomes for mothers and babies.
- United Kingdom: no routine antenatal CTG. NICE tells you to contact maternity services at any time if you are worried about your baby's movements after 24 weeks, and the NHS says the unit will check your baby's movements and heartbeat.
- United States: ACOG says testing for women with a reason for it, such as diabetes, high blood pressure, reduced movements or a pregnancy past 42 weeks, usually starts at 32 to 34 weeks.
- Germany: the maternity guidelines allow a CTG only with an indication: from 26–27 weeks for threatened preterm birth, or from 28 weeks for heart-sound changes or suspected early labour, and repeats for reasons such as twins or a pregnancy past its due date.
- Russia: clinical guidelines schedule a CTG every 2 weeks from 32 weeks.
- Ukraine: the national guideline follows the WHO and does not recommend routine CTG.
- Poland: the perinatal care standard lists a CTG straight after 40 weeks, repeated 7 days later if it is normal.
Wherever you live, the trace is offered whenever there is a concern: fewer movements, bleeding, high blood pressure, a baby measuring small, or a pregnancy running past its due date. Our prenatal tests and scans guide puts it in order with every other check.
Why routine CTG in a healthy pregnancy is not recommended
A Cochrane review of 6 trials with 2,105 women, all with higher-risk pregnancies, found no clear evidence that antenatal CTG improves outcomes for babies. Pointing to that missing benefit in higher-risk pregnancies, the WHO recommends against routine CTG in healthy ones. A CTG has a cost of its own, too: FIGO notes that a routine CTG on arrival in the labour ward for low-risk women was linked to more caesareans, with no better outcomes. Germany's 2023 guideline goes further and advises against any CTG before labour in a low-risk pregnancy.
None of that applies when something has changed. A CTG is the right test when movements slow down, after a fall or bleeding, or when blood pressure rises.
Home CTG and remote monitoring
Some hospitals lend wireless CTG kits to women with high-risk pregnancies, who record a trace at home and send it to the unit to be read. A 2026 review of 39 studies with 7,240 participants found home monitoring no worse than hospital monitoring, though the certainty of the evidence was low. This is supervised care arranged by your hospital. It is not the same as a home Doppler bought online, which the NHS advises against because hearing a heartbeat does not show that a baby is well.
When to call your maternity unit the same day
Call your maternity unit straight away, even at night, if: your baby is moving less than usual or the pattern of movements has changed; you have vaginal bleeding; fluid is leaking from your vagina; you have regular, painful contractions before 37 weeks; or you have severe or constant tummy pain. Do not wait for a booked CTG, and do not use a home Doppler to decide. Call 999 or 911, or your local emergency number, for heavy bleeding or if you collapse.
A normal CTG describes your baby on the day of the test. It does not cover the days after it, so a change in movements always needs a new check. Our guide to your baby's movements explains what to look out for.
Frequently Asked Questions
How long does a non-stress test take?
At least 20 minutes, and German guidance sets 30 minutes as the usual minimum. If your baby is asleep and the trace shows too few accelerations, the test is extended to 40 minutes or longer: FIGO notes that a baby's deep sleep can last up to 50 minutes. A computerised CTG stops as soon as its criteria are met, or after 60 minutes.
What does a reactive non-stress test mean?
It means the baby's heart rate rose at least 2 times within 20 minutes, each rise reaching 15 bpm above the baseline for 15 seconds (before 32 weeks, 10 bpm for 10 seconds). ACOG calls a reactive result reassuring: for now it does not suggest a problem. It describes the day of the test, so a change in movements afterwards still needs a call.
What does a non-reactive non-stress test mean?
It means there were not enough accelerations in 40 minutes. The commonest reason is a sleeping baby, and some medicines have the same effect. The usual next step is a longer recording, a sound stimulus to wake the baby, or a different test such as a biophysical profile. ACOG notes that it can also mean the baby is not getting enough oxygen, which is why it is always followed up.
What does a suspicious CTG mean?
Under FIGO, a suspicious trace lacks at least one normal feature, such as a baseline of 100 to 109 bpm, without any pathological one. FIGO describes it as a low probability of the baby being short of oxygen. The response is to correct anything reversible, such as your position or a fever, and to keep watching or add another test. It is a reason for closer monitoring, not for an emergency.
Does a non-stress test measure contractions?
The second belt does. It records tightenings of the womb, so the printout shows contractions you may not feel, including Braxton Hicks. FIGO notes that this belt shows reliably how often contractions come, not how strong they are. The non-stress test itself is about how the baby's heart rate behaves, and nothing is done to cause contractions.
When do non-stress tests start in pregnancy?
Only when there is a reason, and the timing depends on where you live. ACOG says testing usually starts at 32 to 34 weeks, earlier for some complications. Russia schedules a CTG every 2 weeks from 32 weeks; Poland after 40 weeks. The WHO, the UK, Germany and Ukraine do not offer routine CTG in a healthy pregnancy.
Should I eat before a non-stress test?
Eat normally, but do not expect a sugary drink to change the result. A Cochrane review of 2 trials with 708 women found that giving glucose before the test did not reduce non-reactive results. What does help is a sound or vibration stimulus: in 12 trials it cut non-reactive results and shortened the test.
CTG and the non-stress test at a glance
A CTG prints your baby's heart rate above your contractions. It is read in four features: a baseline of 110–160 bpm, variability of 5–25 bpm, accelerations, and decelerations, which matter by shape and timing. A non-stress test is reactive with 2 accelerations in 20 minutes; a sleeping baby is the usual reason it is not. Fischer scores of 8–10 are reassuring. Routine CTG in a healthy pregnancy is not recommended by the WHO, but reduced movements always need a same-day check.
Inside Baby Novum: the lab results journal keeps each test result with its date and a photo of the printout, so the CTG from this visit sits next to the last one, and the kick counter helps you learn your baby's usual pattern of movements. One journal record is free; Premium keeps them all.
Read next
Sources
- Ayres-de-Campos et al., FIGO consensus guidelines on intrapartum fetal monitoring: cardiotocography (2015)
- NICE NG229 — Fetal monitoring in labour: recommendations
- ACOG — Special tests for monitoring fetal well-being
- Fischer, Stude & Brandt, Zeitschrift für Geburtshilfe und Perinatologie 1976 — A suggestion for the evaluation of the antepartal cardiotocogram
- Ultrasound in Obstetrics & Gynecology 2025 — Performance evaluation of computerized antepartum fetal heart rate monitoring: Dawes–Redman algorithm at term
- Grivell et al., Cochrane Database of Systematic Reviews 2015 — Antenatal cardiotocography for fetal assessment
- Tan & Sabapathy, Cochrane Database of Systematic Reviews 2012 — Maternal glucose administration for facilitating tests of fetal wellbeing
- Tan et al., Cochrane Database of Systematic Reviews 2013 — Fetal vibroacoustic stimulation for facilitation of tests of fetal wellbeing
- PLOS Digital Health 2026 — Remote home cardiotocography: a systematic review and meta-analysis
- WHO recommendations on antenatal care for a positive pregnancy experience (2016), recommendation B.2.3
- NICE NG201 — Antenatal care: recommendations
- DGGG, DEGUM, OEGGG and SGGG S3 guideline 015/089 — Fetal assessment in pregnancy (2023)
- DGGG S1 guideline 015/036 — Use of CTG during pregnancy and labor
- Federal Joint Committee (G-BA) — Mutterschafts-Richtlinie, Appendix II: indications for CTG
- Russian Ministry of Health — Clinical recommendations "Normal pregnancy" (2023)
- Ministry of Health of Ukraine — Clinical guideline "Normal pregnancy" (2022)
- Poland — Perinatal care organisational standard, Dziennik Ustaw 2026 item 1140
- NHS — Your baby's movements
Baby Novum is an informational and tracking tool, not a medical device, and does not provide medical diagnosis or treatment. Always consult your doctor or midwife about your pregnancy.