Late Pregnancy · Fetal Monitoring
Biophysical Profile (BPP)
Ultrasound test of baby's well-being: 5 components (breathing, movement, tone, amniotic fluid, NST). Score 0-10. Used in high-risk pregnancies, reduced movements, post-dates, IUGR. Score 8-10 reassuring; ≤4 may trigger delivery. NICE / ACOG.
Last reviewed 2 June 2026
Biophysical Profile (BPP)
Five-component fetal wellbeing score
Score all 5 components to see the BPP total.
Educational tool only — not medical advice. BPP is performed by trained sonographers; this tool is for understanding the score, not substituting for the assessment. Modified BPP (NST + AFI/SDP alone, Clark 1989) gives similar predictive value in shorter time and is increasingly preferred for routine surveillance.
What does this mean?
The BPP (Manning 1980) looks at five things in a single ~30-minute ultrasound + NST window: breathing movements, body movements, tone, NST reactivity, and amniotic fluid. Each scores 0 or 2 — total 10. The first four reflect the fetal central nervous system in the moment (acute hypoxia is the first thing to suppress them); amniotic fluid reflects chronic placental function over weeks. 8–10 is reassuring, 6 equivocal (repeat in 24 h or move toward delivery if term), ≤ 4 abnormal — typically delivery if ≥ 32 wk; neonatal cooling considered if 0–2 with HIE features. The modified BPP (Clark 1989) uses only NST + AFI/ SDP — quicker, similar predictive value, and is increasingly standard for routine high-risk surveillance.
What is a Biophysical Profile?
Ultrasound-based test of baby’s well-being. Score 0-10. Five components, each 0 or 2:
- Fetal breathing movements — ≥30 sec in 30 min.
- Gross body movement — ≥3 in 30 min.
- Fetal tone — ≥1 extension-flexion.
- Amniotic fluid — deepest pocket >2 cm.
- NST (CTG) — reactive heart rate.
When is BPP done?
- Reduced fetal movements.
- Suspected growth restriction (IUGR).
- Post-dates (≥41 wk).
- Gestational diabetes.
- Chronic hypertension / PE.
- Oligohydramnios or polyhydramnios.
- Previous stillbirth.
- Multiple pregnancies.
Score interpretation
- 8-10: reassuring — continue routine care.
- 6: equivocal — repeat in 24h or extend assessment.
- ≤4: concerning — consider delivery if term; intensive monitoring if preterm.
Amniotic fluid matters most — low fluid alone is concerning.
Full BPP vs Modified BPP
- Full BPP: all 5 components; 30-40 min.
- Modified BPP: NST + AFI only; quicker; ~75% sensitivity of full BPP.
Sleep cycles
Babies sleep ~40 min cycles. Sleeping baby may not breathe or move during scan window. Extend scan, vibroacoustic stimulation, or repeat — usually resolves.
Often combined with
- Growth scan (biometry, EFW).
- Umbilical artery Doppler.
- MCA Doppler (anaemia).
- Uterine artery Doppler.
Different scenarios
Scenario 1: Reduced movements 32 weeks, BPP 8/10
Reassuring. Routine care continues. Increased awareness of movements.
Scenario 2: IUGR 36 weeks, BPP 6/10 + oligohydramnios
Delivery discussion — induction or C-section depending on cervix.
Scenario 3: Post-dates 41+3 weeks, BPP 10/10
Reassuring. Induction planning per NICE NG207 timeline.
Scenario 4: Severe IUGR 28 weeks, BPP 4/10
Antenatal steroids if not given. Magnesium for neuroprotection. Delivery within 24-48h.
Scenario 5: GDM 36 weeks, twice-weekly BPP routine
Surveillance. Normal scores reassuring. Plan delivery 38-39 wk.
Care guidance — BPP
- 30-40 min scan typically.
- Eat beforehand; some sugary food stimulates baby.
- Bladder not critical.
- Sleeping baby may need extra time.
- Combine with growth + Doppler scans.
- Frequency depends on risk.
- Score ≤4 may trigger delivery.
- Continue kick counting between scans.
Sources
- ACOG Practice Bulletin 145. Antepartum fetal surveillance.
- RCOG. Reduced fetal movements (Green-top 57).
- NICE NG121. Caesarean birth (includes fetal surveillance context).
- Manning FA, et al. Antepartum fetal evaluation: development of a fetal biophysical profile.
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Frequently asked questions
What is a Biophysical Profile (BPP)?
ULTRASOUND-BASED test of baby's well-being. SCORE 0-10. Five components, each scored 0 or 2: (1) FETAL BREATHING MOVEMENTS — rhythmic movement of chest/diaphragm for ≥30 sec in 30 min; (2) GROSS BODY MOVEMENT — ≥3 discrete movements in 30 min; (3) FETAL TONE — ≥1 extension-and-flexion (e.g. hand opening/closing); (4) AMNIOTIC FLUID VOLUME — deepest pocket >2 cm; (5) NON-STRESS TEST (NST/CTG) — reactive heart rate pattern. SCORE 8-10 reassuring; 6 equivocal; ≤4 concerning.
When is BPP done?
INDICATIONS: REDUCED fetal movements; SUSPECTED growth restriction (IUGR); POST-DATES pregnancy (≥41 wk); GESTATIONAL DIABETES; CHRONIC hypertension / PE; OLIGOHYDRAMNIOS or polyhydramnios; previous stillbirth; reduced amniotic fluid; suspected fetal anaemia. ANTENATAL TEST — usually after 26-28 weeks (earlier limited usefulness). MULTIPLE pregnancies + Doppler studies often added. ROUTINE in third trimester high-risk pregnancies.
How is BPP done?
ULTRASOUND scan (usually 30-40 min). RADIOGRAPHER or sonographer observes baby's breathing movements, body movements, tone, measures amniotic fluid pocket. CTG / NST separately or before scan. SOMETIMES extended observation if baby asleep. NO CONTRAST or special prep. BLADDER not critical. CAN BE done with mother lying back; some prefer sleep cycle = quiet = repeat scan or vibroacoustic stimulation to wake baby.
What does each component test?
(1) BREATHING — central nervous system intact, no acidosis; sleep cycles affect (~40 min asleep + 30 awake — REPEAT scan if sleeping). (2) BODY MOVEMENT — neuromuscular function. (3) TONE — neurological maturation. (4) AMNIOTIC FLUID — placental function over time (long-term marker). (5) NST — autonomic regulation (short-term marker). BPP COMPREHENSIVE — covers acute + chronic indicators.
What does BPP score mean?
8-10/10: REASSURING. Continue routine pregnancy / repeat as planned. 6/10: EQUIVOCAL. Repeat in 24h or extend assessment. ≤4/10: CONCERNING. Consider delivery (if term); intensive monitoring if very preterm. AMNIOTIC FLUID matters most — even with high score elsewhere, low fluid alone is concerning. AT TERM (37+ wk): low score often triggers delivery. PRETERM: balance baby's gestation vs risk of staying in womb.
What's the difference between BPP and NST alone?
NST = just the heart rate / contractions trace. BPP = NST + 4 ultrasound components. BPP MORE COMPREHENSIVE — assesses multiple aspects. MODIFIED BPP = NST + AMNIOTIC FLUID INDEX only (quicker, ~75% sensitivity of full BPP). FULL BPP for highest concern; modified BPP for routine surveillance.
How long does BPP take?
USUALLY 30-40 minutes — needs 30 min observation of fetal activity. IF BABY ACTIVE: can finish in 20 min (max points achieved). IF BABY SLEEPING: extend to 60-90 min; sometimes return another day. EAT before; some sugary food stimulates baby. NO BREATHING for 30 min from sleeping baby gets repeated until awake. VIBROACOUSTIC STIMULATION (acoustic device) sometimes used to wake.
What if BPP is repeatedly low?
PERSISTENT score 6 or lower despite repeat scans: DELIVERY discussion. AT TERM (37+ wk): often induce or C-section. PRETERM: weigh risks of preterm delivery vs continued in-utero. ANTENATAL STEROIDS if 24-34 wk; MAGNESIUM SULPHATE for neuroprotection if very preterm. SPECIALIST fetal medicine review. EACH WEEK GAINED helps if preterm.
Is BPP accurate?
GOOD but not perfect. NORMAL BPP: stillbirth risk in next week ~1 in 1,000. ABNORMAL: stillbirth risk much higher. FALSE POSITIVES happen — score may improve on repeat. FALSE NEGATIVES rare. CLINICAL CONTEXT matters — combine with growth scans, Doppler studies, fetal movements, other tests. NICE / RCOG support use in high-risk pregnancies.
Can BPP be done alongside other scans?
YES — often combined: GROWTH SCAN (biometry, EFW); UMBILICAL ARTERY DOPPLER (placental flow); MCA DOPPLER (fetal anaemia); UTERINE artery Doppler if applicable. PLUS BPP. FULL fetal assessment ~45-60 minutes total. STANDARD third trimester surveillance for many high-risk women — often weekly.
Can BPP miss things?
YES. Doesn't tell you everything: (1) ACUTE deterioration after scan can happen; (2) NORMAL BPP at the moment doesn't predict 2 weeks ahead; (3) STRUCTURAL anomalies not always visible at later scans; (4) PLACENTAL function declining may have brief normal periods. BPP IS A SNAPSHOT. Combine with fetal movement awareness — call midwife if reduced movements between scans.
Will my baby be born early because of BPP?
DEPENDS. NORMAL BPP: continue pregnancy as planned. ABNORMAL: may trigger DELIVERY. AT TERM (37+): induce or C-section. PRETERM: balance + intensive monitoring; deliver if very abnormal. EARLIER DELIVERY usually better than continued risk if scores severely abnormal. SHARED DECISION with fetal medicine specialist.
What about amniotic fluid volume (AFI / SDP)?
Two ways to measure: AMNIOTIC FLUID INDEX (AFI) — sum of 4 quadrant deepest pockets; normal 5-25 cm. SINGLE DEEPEST POCKET (SDP) — normal ≥2 cm. OLIGOHYDRAMNIOS (low fluid) suggests placental insufficiency. POLYHYDRAMNIOS (high fluid) — gestational diabetes, gut anomalies, infection. SDP now preferred (less false-positive interventions vs AFI). /calculators/afi-sdp for detail.
Do I need BPP every week?
DEPENDS on risk. SEVERE IUGR / oligohydramnios / pre-eclampsia: WEEKLY or twice-weekly. POST-DATES (≥41 wk): twice-weekly BPP often offered. GESTATIONAL DIABETES: weekly third trimester. PREVIOUS STILLBIRTH: weekly. LOWER RISK: less frequent. EACH PROTOCOL individualised by obstetrician.
How does this relate to other calculators on BumpBites?
Companion: /calculators/kick-counter for daily movement monitoring; /calculators/ctg-categorization for NST detail; /calculators/afi-sdp for amniotic fluid; /calculators/fetal-weight for growth; /calculators/mca-psv for Doppler; /calculators/ua-dv-doppler; /calculators/fgr-doppler-composite.