seconds. A NST not meeting the criteria for reactivity is defined as nonreactive and typically requires additional evaluation of the fetus: either additional time for the NST to become reactive or performing a BPP. FIG. 2.1.1 demonstrates a reactive and normal fetal NST, and reflects a normal acid-base balance in the fetus.
FIGURE 2.1.1 A reactive nonstress test (NST) is demonstrated with a normal baseline fetal heart rate (FHR), moderate variability, accelerations, and no decelerations. The maternal and FHR tracings are shown in pink and aqua, respectively.
with absent variability, the rhythm is probably a supraventricular tachycardia (SVT) at a rate of 240 bpm (FIG. 2.1.3). The true FHR, as well as the atrioventricular (AV) relationship, can be determined by ultrasound examination.
TABLE 2.1.1 COMPONENTS OF THE 8-POINT BIOPHYSICAL PROFILE SCORE
TABLE 2.1.2 MONITORING CHARACTERISTICS OF ARRHYTHMIAS