Components and clinical significance of markers
To form an objective picture of the child's condition, several parameters are evaluated. They are divided into two groups depending on the rate of reaction to pathological changes:
- Markers of acute impairment. These include the results of the non-stress test (NST), as well as ultrasound indicators: the presence of breathing movements, general motor activity, and muscle tone. These parameters change first during a sudden deterioration of blood supply.
- Markers of chronic impairment. These include the volume of amniotic fluid and the degree of structural maturity of the placenta. Deviations in these indicators suggest that the pathological process has been ongoing for some time.
Diagnostic algorithm and interpretation of results
The assessment begins with a non-stress test. If a reactive NST is recorded (normal heart rate response to movements), no additional data is required—the condition is considered satisfactory. However, if the test is non-reactive, this is a direct indication for a detailed ultrasound examination of all other components.
Based on the examination, each parameter is evaluated in points, which are then summed up:
- 8–12 points: normal, intrauterine condition is reassuring.
- 6–7 points: equivocal result. Dynamic monitoring and a repeat examination are required.
- ≤ 5 points: critical indicator pointing to pronounced intrauterine fetal hypoxia.
Scoring criteria
Each sign is assigned from 0 to 2 points depending on severity.
| Parameter | 2 points (Normal) | 1 point (Borderline condition) | 0 points (Pathology) |
|---|---|---|---|
| Non-stress test | $\ge$ 5 accelerations (amplitude $\ge$ 15 bpm, duration $\ge$ 15 s) per 20 min | 2 to 4 similar accelerations per 20 min | 1 acceleration or none per 20 min |
| Motor activity | $\ge$ 3 generalized movements per 30 min | 1–2 generalized movements per 30 min | Complete absence of movements per 30 min |
| Breathing movements | $\ge$ 1 episode with duration $\ge$ 60 s per 30 min | $\ge$ 1 episode with duration from 30 to 60 s per 30 min | Absence of episodes or duration < 30 s |
| Muscle tone | $\ge$ 1 episode of limb return from extension to flexion | At least 1 episode of limb return from extension to flexion | Limbs remain in extension |
| Amniotic fluid | Vertical pocket of a free space 2–8 cm | $\ge$ 2 pockets sized 1–2 cm | Pocket of free space less than 1 cm |
| Placental maturity | Fully corresponds to current gestational age | — | Grade III maturity at gestational age under 37 weeks |
Additional methods for hemodynamic assessment
In addition to the biophysical profile, dopplerometry of blood flow in the mother-placenta-fetus system plays a crucial role. In uncomplicated pregnancy, peripheral vascular resistance gradually decreases, which is expressed in the reduction of blood flow indices (e.g., systolic-diastolic ratio). Increased resistance leads to an increase in these indices.
The following vascular beds are studied:
- Uteroplacental: uterine arteries and their branches (arcuate, radial, spiral).
- Fetoplacental: umbilical artery.
- Fetal hemodynamics: aorta and cerebral vessels (specifically, the middle cerebral artery).
- Venous blood flow: the key vessel is the ductus venosus (ductus venosus).
Color Doppler mapping (CDM) is also used. The method allows visualization of circulation in the intervillous space, detection of retroplacental hemorrhage, nuchal cord, vascular anastomoses in multiple pregnancies (twin-to-twin transfusion syndrome), and congenital heart defects.
For quick memorization of acute markers, use the acronym "BMT + Pulse": Breathing, Movements, Tone, and heart rate (NST). These are parameters that react to oxygen deficiency "here and now".
Class and exam questions
In which trimester is the biophysical profile assessed?
The study is used in the 3rd trimester of pregnancy to monitor the intrauterine condition of the fetus.
What to do if the BPP score is 6?
A score of 6–7 points is considered equivocal. In such a situation, a repeat examination must be scheduled to clarify the condition.
Why is blood flow in the ductus venosus assessed?
Examination of the ductus venosus has great diagnostic significance for the comprehensive assessment of fetal venous hemodynamics alongside the arterial bed.
What else to study on this topic
- Norms of the systolic-diastolic ratio (SDR) in the 3rd trimester
- Color Doppler mapping (CDM) in multiple pregnancy
- Indications and approaches for neonatal neurosonography
- Diagnosis of intracranial hemorrhages and cerebral ischemia in infants
- Fetoscopy: indications for intrauterine surgical interventions
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