All that follows is from Chapter E in the Advanced Life Support in Obstetrics (ALSO) Course Manual, June 2011, Intrapartum Fetal Surveillance:
INDICATIONS FOR CONTINUOUS ELECTRONIC FETAL MONITORING (CEFM)
Indications for CEFM include maternal medical problems, pregnancy related risk factors and labor complications:
Maternal indications (antenatal) are hypertension (preeclampsia, eclampsia), diabetes, cardiac disease, hemoglobinopathy, severe anemia, hyperthyroidism, collagen vascular disease, and renal disease.
Maternal indications (intrapartum) are vaginal bleeding in labor, and intrauterine infection.
Fetal indications (intrapartum) are meconium stained amniotic fluid, suspicious fetal heart rate on auscultation, abnormal fetal heart rate on the admission tracing (20 min. strip), and post term pregnancy.
Fetal indications (antepartum) are multiple pregnancies, intrauterine growth restriction, preterm labor (less than 37 weeks), breech presentation, Rh isoimmunization, oligohydramnios, and abnormal umbilical artery Doppler velocimetry.
Labor indications are induced or augmented labor, prolonged labor, regional analgesia, particularly after initial bolus and after top ups, thick meconium, abnormal fetal heart rate or concerning decelerations in structured intermittent auscultation, vaginal bleeding in labor, abnormal uterine activity, and the previous cesarean section.
DR C BRAVADO
The mnemonic DR C BRAVADO is a systematic approach to the interpretation of FHR tracings for both CEFM and SIA (Structured Intermitent Auscultation).
Category I Fetal Heart Rate tracings
Category I tracings are normal tracings that are strongly predictive of normal fetal pH status at the time of observation and must include all of the following:
- baseline of 110 to 160 bpm
- moderate baseline variability [meaning 6 to 25 bpm amplitude range]
- late or variable decelerations are absent
- early decelerations may be present or absent
- accelerations may be present or absent
Generally, Category I tracings are considered normal and can be followed routinely.
Category II Fetal Heart Rate tracings
Indeterminant tracings are not predictive of fetal acid-base status and cannot be classified as either I or III. The presence of moderate variability or accelerations is highly predictive of normal fetal acid-base status. These tracings require prompt evaluation and efforts to resolve the tracing. Category II tracings may show any of the following:
- baseline with absent, minimal, or marked variability
- recurrent variable decelerations with minimal to moderate variability
- recurrent late decelerations with moderate variability
- variable decelerations with slow return overshoot or “shoulders”
- prolonged deceleration
- no acceleration after fetal stimulation
Category II tracings are indeterminate and not predictive of abnormal pH status. These tracings require prompt evaluation and efforts to resolve the tracing.
Category III Fetal Heart Rate tracings
These tracings are predictive of abnormal fetal pH status. These require prompt evaluation and consideration of immediate delivery. These include:
- sinusoidal pattern
- absent fetal heart rate variability with any of the following:
- recurrent late decelerations
- recurrent variable decelerations
These tracings [the above] are predictive of abnormal fetal pH status. These require prompt evaluation and consideration of immediate delivery.
Documentation of fetal heart tracing and categorization during labor should include:
- fetal heart rate data (i.e., baseline rate, variability, periodic changes and categorization)
- uterine activity characteristics obtained by palpation or pressure transducer (i.e., frequency, duration, intensity and whether tachysytole is present)
- specific actions taken when changes in fetal heart rate occur
- other maternal observations and assessments
- maternal and fetal responses to interventions
- subsequent return to normal findings
Various intrauterine resuscitative measures for category II or category III tracings or both
- initiate lateral positioning (either left or right)
- administer maternal oxygen
- administer intravenous fluid bolus
- reduce uterine contraction frequency
- discontinue oxytocin or cervical ripening agents
- administer tocolytic medication (e.g., terbutaline)
- initiate maternal repositioning
- initiate amnio infusion
- if prolapsed umbilical cord is noted, elevate the presenting fetal part while preparations are underway for operative delivery
And always check the cervix and the maternal vital signs [including oximetry]
Ancillary testing for Category II and III fetal heart rate tracings
Fetal scalp pH testing is no longer commonly performed in the United States and has been replaced with fetal stimulation or immediate delivery (by operative vaginal delivery or if necessary cesarean section). A meta-analysis showed that if there is absent or minimal variability without spontaneous accelerations, the presence of an acceleration after scalp stimulation or fetal acoustic stimulation indicates that the fetal pH is greater than 7.20. If the fetal heart tracing remains abnormal then these tests the may need to be performed periodically and consideration for emergent cesarean or operative vaginal delivery is usually recommended. Cord blood gases are recommended after a delivery for an abnormal heart tracing.