The biophysical profile is a means of assessing fetal wellbeing utilizing five measurable parameters. Each parameter is given a score of 0 (if absent) or 2 (if present): thus the score may be 0—10. Ventzileos et al (1983) have added placental grade to the profile, although placental grading is not used in most departments. Low scores are associated with poor outcome. The following parameters are included in the assessment.
· Fetal breathing movement-Real time US is used to assess breathing movements. The presence of at least one period of breathing lasting 60 seconds or more in a 30 minute period is considered normal. Hiccup and fetal movements are not counted.
2 = 30 seconds sustained breathing/30 minutes
0 = <30 seconds of sustained breathing/30 minutes.
· Fetal movements- Gross movements are recorded over 30 minutes: simultaneous limb and trunk movements are scored as a single event. Three movements over a 30 minute period are considered normal. The fetus is most active 1 hour after the mother has eaten.
2 = 3 gross movements/30 minutes
0 = <3 movements/30 minutes.
· Fetal tone- Flexion of the trunk with both the upper and lower limbs flexed is considered normal. If fetal extension is not followed rapidly by flexion, or the spine is extended with extended limbs or only partially flexed limbs, then tone is reduced. These fetuses hold their hands ‘open’.
2 = closed fists, flexed fetus/flexion from extension
0 = neither of above.
· Amniotic fluid volume- Amniotic fluid volume is measured in areas free of small parts. OH is present when the largest pocket of fluid is less than 2 cm. A four quadrant assessment is however usually made;, the sum of fluid depths (amniotic fluid index) should be more than 5 cm.
2= pockets of amniotic fluid > 1 cm i.e. normal liquor volume
0= pockets of amniotic fluid < 1 cm i.e. oligohydramnios.
· Non-stress test- The fetal heart rate is continuously monitored with Doppler ultrasound with simultaneous assessment of fetal movement by tachynamometer. Two accelerations of fetal heart rate of at least 15 beats/mm above the baseline, associated with fetal movements lasting at least 15 seconds, must be present within a 20 mm period for the test to be positive.
2 = 2 or more accelerations/20 minutes
0 = <2 accelerations.
· Nuchal cord compression stress test- External pressure with the ultrasound probe is applied over the nuchal cord for 10 seconds, causing venous occlusion (assessed on color Doppler). The fetal heart rate rises by 20—3 0 beats/mm after the pressure is released, returning to normal by 60 seconds. This response is reduced or absent when the fetus is hypoxic.
· Placental grade- Echogenicity and appearance of the maturing placenta have been used to assess placental grading (see p. 87): placental grade does not correlate well with fetal outcome and is therefore not included in the biophysical score in most departments.
2 = grade 0, 1 or 2 placenta
I = indeterminate placenta
0= grade 3 placenta.