- ATHENS OFFICE MED4WOMAN ATHENS
- VOLOS OFFICE MED4WOMAN VOLOS
Obstetrician-Gynecologist
PhD, University of Athens Medical School
Obstetrician-gynecologist Panagiotis Polyzos practices at the Institute of Life, the IVF Unit of IASO Maternity Hospital.
The biophysical profile is a prenatal test used to assess the fetus's well-being. The test combines fetal heart rate monitoring (NST – Non-Stress Test) and ultrasound evaluation of the fetus by assessing:
Each parameter is scored 2 points if normal and 0 points if abnormal. The total score reflects the fetus's intrauterine condition. The maximum possible score is 12, and the minimum is 0.
After scoring each parameter individually, the points are summed to obtain the final score. Thus, a total score:
A biophysical profile is used to assess and monitor the health of the fetus. The goal of a biophysical profile is to prevent pregnancy loss and to detect low oxygen supply to the fetus (fetal hypoxia) early enough so that the baby can be delivered without sustaining permanent damage.
A biophysical profile is performed more often when there is an increased risk of complications that could lead to pregnancy problems or preterm birth.
The biophysical profile is usually done after week 32, or earlier in high-risk pregnancies. It is painless and completely safe for mother and fetus. The ultrasound part lasts up to 30 minutes, as long as needed to observe the baby's movements, tone and breathing movements, and it is combined with cardiotocography (NST), which lasts 20 to 40 minutes.
No special preparation is needed. A light meal before the test helps, because the baby is usually more active after eating. If the fetus is asleep, the test may be extended or repeated.
A low score does not necessarily mean there is a problem. The fetus may simply have been asleep, or the mother may have taken medication that calms it. That is why a borderline result is usually repeated within 24 hours and evaluated together with Doppler, fetal growth and gestational age. The decision to deliver is never based on a single number.
Between tests, the best indicator is the movements you feel yourself. If you notice a clear decrease, contact your doctor the same day. See what else is checked in the third trimester of pregnancy.
In its classic form, as described by Manning, the biophysical profile evaluates five parameters, each scored 2 or 0 points, for a maximum of 10. Some centers add the placental maturity grade, bringing the scale to 12. Observation takes place within a time window of up to 30 minutes, and each parameter has a specific, measurable criterion:
The four ultrasound parameters are often completed within a few minutes when the baby is awake. If all are normal, some protocols consider a score of 8 out of 8 reassuring even without the NST.
The value of the biophysical profile rests on a simple physiological observation. Fetal activities are controlled by brain centers that mature in different weeks. Muscle tone appears first, around week 8. Body movements follow, then breathing movements, and last, toward the end of the second trimester, the link between heart rate and movements, that is, NST reactivity.
When oxygen supply decreases gradually, these functions are lost in reverse order. NST reactivity and breathing movements “switch off” first. Later, body movements become less frequent. Tone is lost last, which is why its absence is considered a serious finding.
Amniotic fluid works differently. It does not show what is happening right now, but what has been happening for days or weeks. In chronic hypoxia the fetus redistributes its blood toward the brain, heart and adrenal glands. Blood flow to the kidneys decreases, and with it urine production, which makes up most of the amniotic fluid in the second half of pregnancy. So the four “acute” parameters reflect the current state, while the fluid gives the long-term picture.
In many obstetric centers, especially when monitoring is needed once or twice a week, the modified biophysical profile is used. It combines only two elements: the NST, which reflects current oxygenation, and the amniotic fluid measurement, which reflects placental function over time.
The result is considered normal when the NST is reactive and the amniotic fluid index (AFI) is above 5 centimeters or the deepest vertical pocket is at least 2 centimeters. If either does not meet the criteria, the doctor usually proceeds to a full biophysical profile or additional tests.
According to the American College of Obstetricians and Gynecologists (ACOG), the predictive value of the modified version is comparable to that of the full biophysical profile. The advantage is practical: less time at the office, without sacrificing reliability. The choice between the two versions depends on the indication, gestational age and previous findings.
Fetal sleep is the best-known cause of a falsely low score. But it is not the only one. Some conditions temporarily change the baby's behavior without meaning it lacks oxygen:
That is why you should always tell your doctor about every medication you take and any recent injections. The same score can mean something completely different in two different women.
The biophysical profile is rarely evaluated on its own. In pregnancies with fetal growth restriction, the main monitoring test is umbilical artery Doppler, because it shows how the placenta is working. When flow is normal, the risk to the fetus is low. When end-diastolic flow is reduced, absent or reversed, monitoring becomes more frequent and the biophysical profile helps decide the right time for delivery.
In preterm fetuses with severe growth restriction, other vessels are also examined, such as the middle cerebral artery and the ductus venosus. Ultrasound weight estimation is repeated every two to three weeks and not more often, because over shorter intervals the measurement error exceeds the actual growth.
A similar approach is used in other conditions, such as high blood pressure in pregnancy or diabetes treated with medication. The monitoring plan is built from a combination of tests, not from a single measurement. To see when each ultrasound check is done during pregnancy, visit the page on obstetric ultrasound.
No fetal well-being test is perfect. The strength of the biophysical profile is that a normal result is truly reassuring. In large patient series, the risk of stillbirth within one week of a normal biophysical profile was below 1 in 1,000.
Its weak point is false positive results. A low score is often not confirmed on repeat testing and, if interpreted hastily, can lead to unnecessary induction of labor or a cesarean section. There are also things the test does not predict:
The test answers one specific question: is the fetus well oxygenated right now? Everything else requires other tools.
The biophysical profile gives a “snapshot” of the moment. On the other days, the most useful tool is you. RCOG guidelines do not require strict kick counting. They do, however, ask every pregnant woman to know her baby's own pattern of movements.
A woman who reports reduced movements usually has an NST the same day and, depending on the findings, an ultrasound or biophysical profile.
The test does not require fasting or a full bladder. A little organization, however, makes interpretation more accurate and your conversation with the doctor more productive.
Allow 45 minutes to an hour in total at the office, so you are not rushed if the baby needs more time to “show” all its movements.
Usually from week 32 onward when there is an indication, or after week 40 in a prolonged pregnancy.
Yes. It is based on ultrasound and heart rate recording, with no radiation or intervention.
It depends on the indication. In high-risk pregnancies it is done once or twice a week.
The NST records only the fetal heart rate and uterine contractions. The biophysical profile adds an ultrasound assessment of movements, tone, breathing movements and amniotic fluid.
Yes. Each fetus is evaluated separately, with its own score and its own amniotic fluid measurement in its own sac. The test takes longer and requires careful identification of each fetus so that the findings are attributed correctly.
The acute parameters are normal, but oligohydramnios may indicate chronic placental compromise or ruptured membranes. Further investigation is needed. At term, delivery is often discussed, while in a preterm pregnancy closer monitoring is the usual approach.
Studies have not shown that glucose or juice meaningfully increases fetal movements. A normal, light meal is enough. If you have gestational diabetes, eat according to your meal plan and do not stop your treatment.
The test is usually done with a slight tilt to the left or with short breaks, so that the uterus does not press on the large veins of the abdomen. Tell the staff right away if you feel dizzy, nauseous or short of breath.
