••• Chapter 4^ Antepartum Management and Fetal Surveillance^49
- Decelerations:
- Recurrent variable decelerations plus minimal or moderate variability
- Prolonged decelerations
- Recurrent late decelerations with moderate variability
❍ What defines a FHR Category III tracing?
- Absent variability plus any of the following:
- Recurrent late or variable decelerations
- Bradycardia
Or
- Sinusoidal pattern (visually apparent, smooth, sine wavelike undulating pattern in FHR baseline that persists
for >20 minutes)
❍ Fetal scalp stimulation is used to improve?
Variability, and adequate response represents a nonacidotic fetus.
❍ What are the advantages of an internal scalp electrode monitor?
Fetal variability is more apparent, easier to continuously follow FHR despite movement of fetus or mother,
and decreased chance of inadvertently monitoring maternal pulse instead of FHR.
❍ What are the disadvantages of an internal scalp electrode monitor?
Necessity of rupture of membranes for placement and a slightly increased risk of fetal infection or scalp hematoma.
Risk of vertical transmission of infections.
❍ In what maternal conditions should application of a fetal scalp electrode be avoided?
Hepatitis B and HIV infection.
❍ What are the potential causes of a sinusoidal FHR pattern?
Maternal-fetal hemorrhage, Rh isoimmunization, and fetal hypoxia, often resulting from severe chronic fetal
anemia, or administration of narcotic drugs to the mother.
❍ What are the potential causes of fetal tachycardia?
Maternal fever, chorioamnionitis, fetal anemia, illicit drug use, congenital heart disease, sympathomimetic drugs
(ie, terbutaline), fetal hypoxia, and acidosis.
❍ What are the potential causes of fetal bradycardia?
Acute cord compression or prolapse, rapid descent of the fetal head in labor, uterine hyperstimulation, maternal
hypotension, congenital heart block, inadvertent monitoring of maternal pulse, uterine dehiscence, severe fetal
hypoxia, and placental abruption.
❍ What are the potential causes of decreased variability?
Fetal sleep cycle, hypoxia, narcotics, CNS anomalies, and magnesium sulfate.