Category Fetal Monitoring

In this blog I’ll highlight a case scenario specific to intrapartum management of a persistent Category II fetal heart rate (FHR) tracing.  The longitudinal evolution of the tracing will be highlighted as well as the perinatal care delivery responses.  In closing, I’ll offer current recommendations regarding the management of persistent Category II FHR tracings with high-risk findings. 

Case Scenario: Persistent Category II FHR Tracing

Patient Profile: A woman in active labor whose FHR tracing changes from Category I to Category II. Labor is being augmented with Oxytocin. Position change is the only documented intervention. 

Tracing Observations: The fetal monitor shows a baseline FHR of 130 bpm, moderate variability, accelerations absent and intermittent late decelerations. A normal contraction pattern is observed. 

Obstetrical provider order, note and plan of care: increase Pitocin as reassured by moderate variability.

Four hours later: The fetal monitor shows a baseline of 140 bpm, moderate variability, absent accelerations, recurrent late decelerations with intermittent variable decelerations and one prolonged deceleration.

(Image: Category II FHR tracing with late decelerations)

Birth Outcome: Vaginal birth of viable newborn requiring resuscitative efforts. Apgar scores: 2/4/6/6. Arterial cord blood gas: pH 6.9, BE -14. Transferred to NICU requiring therapeutic hypothermia for moderate to severe encephalopathy.

Comments: Prolonged or repetitive intrapartum fetal hypoxemia can lead to fetal acidemia.  Fetal acidemia is associated with adverse neonatal outcomes, including encephalopathy and cerebral palsy. 

Category II FHR tracings are the most common pattern associated with perinatal litigation claims involving hypoxic ischemic encephalopathy. Category II FHR tracings present with much heterogeneity, meaning, the presence of a broad range of patterns with various risk levels for the fetus.  This can make it difficult to determine if the Category II tracing is indicative of current or impending fetal acidemia.  This is why it’s crucial for all members of the perinatal team to further characterize the features of a Category II FHR, as well as the development of certain features over time.  Characteristics of FHR tracings that are considered high risk, meaning, those features that have a greater likelihood of indicating fetal hypoxia or acidemia, are referenced below:

• Absent baseline FHR variability
• Prolonged, otherwise unexplained, minimal variability
• Unexplained change in baseline from normal to tachycardia
• Recurrent late, recurrent variable, or more than one prolonged deceleration

It’s important to be aware that currently, there is insufficient high-quality data to support the presence of moderate variability and / or fetal accelerations as markers of fetal well-being in the presence of Category II FHR tracings with high-risk features.

Recommended Management: In the setting of a persistent Category II FHR tracing, intrauterine resuscitation is required – maternal position change, amnioinfusion for variable decelerations, intravenous fluid bolus, discontinuation of augmentation or induction agents, oxygen, correction of maternal pathophysiology thought to be associated with the FHR tracing changes.  Communication with the attending obstetrical provider is warranted. 

The perinatal care team should also systematically consider individual characteristics of the hospital, available staff, patient, fetus and labor.  Consideration must be made specific to labor progress, proximity to delivery, as well as maternal, fetal and labor risk factors when determining a management plan and timing of delivery. 

If the above conservative resuscitative measures are unsuccessful, the obstetrical provider must decide whether to wait for spontaneous vaginal birth or to expedite delivery by other means (operative birth if appropriate, or cesarean section).  This decision requires clinical judgment, weighing the estimated time until vaginal birth against the estimated time until the onset of potential injury.

In 2013 Clark et al. proposed a standardized approach to managing persistent Category II FHR tracings, as outlined below:

• Moderate variability or accelerations in the presence of significant decelerations with normal labor progress: expectant management with close observation regardless of the presence of decelerations. Exception: presence of prolonged decelerations
• Moderate variability or accelerations in the presence of significant decelerations with abnormal labor progress: cesarean section should be considered
• Absent moderate variability and accelerations with recurrent significant decelerations with failure to respond to above corrective measures for 30 minutes: delivery should be considered
• Absent moderate variability and accelerations in the absence of significant decelerations: delivery should be considered after 60 minutes if not responsive to interventions

In 2018 the Clark Algorithm was produced which describes a standardized approach to managing Category II FHR tracings with recurrent significant FHR decelerations based on FHR baseline variability.  Significant decelerations are defined as late decelerations, variable decelerations lasting 60 seconds and reaching a nadir of ≤ 60 bpm or at least 60 bpm below baseline, or prolonged decelerations.  See referenced algorithm below:

Closing Thoughts: Category II FHR tracings are the most complex to analyze and to manage.  In the setting of persistent Category II FHR tracings, a common, preventable error in management is to postpone expedited delivery in the hope that the FHR tracing will resolve spontaneously.  To reduce adverse outcomes as well as liability risk, efforts should be made to timely identify and treat Category II FHR tracings.  In the setting of a clinical indication to expedite delivery, effort should be made to refrain from delaying decisions that are required to be made. 

References

AAP, ACOG, 2017. Guidelines for Perinatal Care

ACOG, 2025. Intrapartum Fetal Heart Monitoring: Interpretation and Management

Miller et al., 2027. Pocket Guide to Fetal Monitoring

COMMENT AND SHARE: Do you anticipate a change in the way you interpret and / or manage persistent Category II FHR tracings following review of this post?

Case Review: 21-year-old primiparous (first pregnancy) at 35+4 weeks gestational age presents to labor and delivery triage status post a motor vehicle accident (MVA) 4 hours prior to arrival.  Patient reports occasional mild uterine contractions on arrival. Denies vaginal bleeding, or leaking of fluid.  Reports decreased fetal movement since the MVA.  Obstetrical history is significant for anemia, and O negative blood type.

1:30pm: RN progress note – occasional mild uterine contractions. Abdomen soft, non-tender. FHR 125 with moderate variability. Occasional accelerations. Absent decelerations. Occasional mild uterine contractions. Category I fetal heart rate (FHR) tracing reported to attending Ob/Gyn via telephone (in reference to above tracing).

5:30pm: RN progress note – Telephone report provided to Dr. Z. Category I tracing. Reassuring maternal, and fetal status. Rhogam administered. Orders received to discharge patient home with follow up in office as previously scheduled.

11:30pm: Patient returned to labor and delivery triage with onset of painful uterine contractions, and vaginal bleeding. Uncertain if perceiving fetal movement.  Abdomen rigid, and tender to touch. Fetal heart tones absent. Intrauterine fetal demise confirmed via bedside obstetrical ultrasound. Patient desires primary cesarean section.  Placenta abruption confirmed at delivery.

Sinusoidal FHR Pattern: A sinusoidal FHR pattern is uncommon.  The smooth, sine wave-like undulating pattern in the FHR baseline serves to distinguish this pattern from variability.  In the presence of a sinusoidal FHR pattern, there is a cycle frequency of 3 to 5 per minute that persists for 20 minutes.  A sinusoidal FHR pattern can be misinterpreted as moderate variability.  This misinterpretation puts the team (including the patient, and her family) at risk for misdiagnosis, and mismanagement.

An effective way to distinguish FHR  variability from the sinusoidal pattern is by recognizing that variability is defined as fluctuations in the baseline that are irregular in amplitude, and frequency.  By contrast, the sinusoidal pattern is characterized by fluctuations in the baseline that are regular in amplitude, and frequency.  Spontaneous accelerations are absent, nor are they elicited in response to uterine contractions, fetal movement, or stimulation (i.e., digital scalp stimulation, vibroacoustic stimulation).

Causes:  Causes of a sinusoidal FHR pattern can include fetal anemia as a result of Rh isoimmunization (i.e., the mother’s blood protein is incompatible with the fetus’s in the case of a maternal Rh negative [O negative] blood type), fetal maternal hemorrhage (i.e., placenta abruption), twin-to-twin transfusion syndrome, ruptured vasa previa, and fetal intracranial hemorrhage.  Other fetal conditions that have been reported to be associated with a sinusoidal FHR pattern include fetal hypoxia or asphyxia, fetal infection, fetal cardiac anomalies, and gastroschisis. 

Pseudosinusoidal, or medication induced sinusoidal can occur after the administration of some opioids, fetal sleep cycles, or rhythmical movements of the fetal mouth.  These events are of short duration, preceded, and followed by an FHR with normal characteristics.  These short periods of sinusoidal appearing patterns do not require treatment.

Significance / Management: A sinusoidal FHR pattern is associated with an increased risk for fetal acidemia at the time of observation.  This pattern is to be considered a Category III (abnormal), which requires immediate evaluation, intrauterine resuscitation, and expedited birth if unresolved. 

References

Lydon, and Wisner, (2021). Fetal Heart Monitoring Principles and Practices

Miller et al., (2022). Mosby’s Pocket Guide to Fetal Monitoring

Simpson et al., (2021). Perinatal Nursing

P.S. COMMENT AND SHARE: What is your experience reviewing a case involving a sinusoidal FHR pattern? Was the abnormal pattern identified timely? Was the pattern misinterpreted as moderate variability? What was the neonatal outcome?

Fetal heart rate (FHR) pattern interpretation, communication, and documentation is a common area of liability.  Reviewing the standards of care that support verdicts, as well as learning from past plaintiff, and defense counsel allegations, aids in the ability to bridge the gap between perinatal medicine, and the law.   

In this blog, I’ll be reviewing a medical malpractice birth injury case with a theme specific to failure to monitor, as well as failure to identify, and act on a non-reassuring fetal heart rate tracing.  I’ll discuss allegations from both the plaintiff and defense counsels that led to the plaintiff verdict.  Facts of the case will be reviewed, and medical legal risk reduction strategies will be offered, specific to fetal heart rate monitoring interpretation, communication, documentation, and education.  The referenced risk reduction strategies represent current evidence-based standards of care specific to electronic fetal monitoring.   

Case Facts: On April 4, 2013, Ms. Jones, a 24-year-old, who was 40 weeks pregnant, presented to University Medical Center for a routine prenatal exam, and reported she was experiencing some contractions. She underwent a non-stress test, which was completely normal, and reassuring. Jones was sent home, and was instructed to return for routine testing one week later. That night, April 4, 2013, at approximately 2:01 a.m., Jones was admitted to the University Medical Center’s triage unit for observation after she reported decreased fetal movement.  Jones was evaluated in triage with a series of tests, including a non-stress test, and an attempted vibroacoustic stimulation. The non-stress test was not reactive, and the vibroacoustic stimulation failed. The resident doctors admitted Jones for non-reassuring fetal well-being, and delivery for fetal distress at approximately 4:20 a.m. At approximately 5:20 a.m., Jones was transferred into a labor room from triage at the hospital’s labor and delivery unit. Instead of performing a cesarean section for non-reassuring fetal well-being, and fetal distress, at approximately 7:53 a.m., Jones was induced for a trial of labor with the induction agent Cervidil (Dinoprostone). The fetal heart rate remained non-reassuring throughout Jones’ labor according to all medical records, and all testimony at trial. After approximately 11 hours of non-reassuring fetal heart rate tracing, and a failed induction of labor, Jones was evaluated by a board-certified attending physician for the first time at 1:05 p.m. Following the attending physician’s evaluation, a decision was made to proceed with an emergency cesarean section for fetal distress, according to numerous medical records. At approximately 1:49 p.m., Jones gave birth to plaintiff newborn Jones. The birth was performed by cesarean section. Newborn Jones was admitted to the hospital’s neonatal intensive care unit, and remained an inpatient for three weeks.

Plaintiff Counsel Allegations: Plaintiffs’ counsel alleged that the party sued was negligent in its treatment of Jones and that it failed to deliver her unborn baby immediately by cesarean section, and instead induced her with a contraindicated induction of labor medication. Counsel asserted that it was a violation of the standard of care to induce Jones for vaginal delivery, despite obvious, and documented non-reassuring fetal well-being, and fetal distress for a period of about 12 hours. The experts opined the nursing staff failed to properly assess, and analyze the fetal heart monitor, and the signs of fetal distress, failed to properly communicate with the attending physicians, failed to advocate for the safety of newborn Jones, including preventing the administration of a contraindicated medication, and advocating for earlier necessary delivery. The Jones’ maternal fetal medicine expert, and obstetrical expert testified that the attending physicians at the sued hospital deviated from the standard of care by failing to personally evaluate Jones considering the documented findings of non-reassuring fetal well-being, and fetal distress. The experts stated the attending physicians failed to properly oversee the resident doctors who were managing Jones improper induction. Ultimately, the experts opined that all of the attending physicians, and the residents deviated from accepted practice by attempting to induce Jones instead of performing an immediate cesarean section at or around the time she arrived to the hospital with identified fetal distress. The maternal fetal, and obstetrical experts concluded that had newborn Jones been delivered by cesarean section, as was required by the standard of care, he would not have suffered from brain damage

Defense Counsel Allegations: Defense counsel contended nothing it did was negligent, and that Jones’ brain damage was caused by an undiagnosed, in utero infection that occurred sometime before April 4, 2013. The defense contended there was no significant hypoxia since the cord gases showed normal oxygen, and only mild acidemia that would not account for the significant brain damage. There were other objective laboratory results that could only be explained by an event more than 24 hours prior to delivery. The only explanation that would explain everything was an in-utero infection, supported by chorioamnionitis on the placental pathology, and the mother’s complaint of decreased fetal movement for 24 hours. Furthermore, the monitor strips, and other information required continued monitoring but not an immediate or emergency cesarean section. The hospital’s expert neonatologist testified that there was an in-utero event that caused brain damage at least 24 hours prior to delivery. The most likely cause of the brain damage, based on laboratory results including the cord gases, was an infection that occurred at least 24 hours prior to the delivery, and an earlier delivery would not have changed the outcome. The defense’s expert in obstetrical nursing opined that the fetal monitor strips were stable throughout, that the nursing monitoring was within the standard of care, and that there was no reason for the nurses to “go up the chain of command” to suggest an immediate cesarean section. The hospital’s expert in maternal fetal medicine testified that the cord gases ruled out hypoxic injury during the time of the hospitalization. Additional objective laboratory evidence clearly supported an injury at least 24 hours prior to delivery. This was supported by Jones’ complaint of decreased fetal movement on arrival at the hospital, and chorioamnionitis on the placenta pathology report. Furthermore, the fetal monitor strips were stable throughout Jones’ course at the hospital, and there was nothing requiring a decision to proceed to immediate cesarean section in this first-time mom until that decision was reached.

Result: Plaintiff verdict in the amount of $53 million.  Injury type(s): brain-cerebral palsy; mental/psychological-birth defect; mental/psychological-learning disability; mental/psychological-cognition, impairment; pulmonary/respiratory-hypoxia

Standard of Care Takeaways:

• Fetal heart rate (FHR) pattern interpretation, communication, and documentation is a common area of liability, and patient harm.
• Use of the standardized nomenclature recommended by the National Institute of Child Health, and Human Development (NICHD) to describe FHR patterns in all professional communication, and medical record documentation is the standard of care.
• FHR assessment must include baseline FHR, variability, presence or absence of accelerations, and decelerations, and pattern evolution when communicating normal, abnormal, and indeterminate FHR patterns.
• Ensure that agreed upon definitions of fetal well-being are established, and documented on admission prior to induction or augmentation of labor, initiation of epidural analgesia, patient transfer, and discharge.
• Develop common expectations for intrauterine resuscitation based on the presumed etiology of the FHR pattern.
• Establish agreement among team members specific to which types of FHR patterns require bedside evaluation by the primary (supervising or collaborating) care provider, and timeframe involved.
• Organizations should require ongoing multidisciplinary fetal monitoring education.  Organizations should require all nurses, physicians, residents, and advanced practice RN’s (midwives, nurse practitioners, physician assistants) responsible for care of pregnant women to demonstrate competency in interpreting electronic fetal monitoring (EFM) data.

Closing: Birth injury cases allegedly involving an acute ischemic event during the labor course can be challenging in the absence of understanding the physiology behind fetal monitoring interpretation.  Additionally, knowledge of expected communication, and documentation specific to clinical findings are crucial to understand in an effort to defend a birth injury case with a theme central to failure to monitor, and/or failure to identify, and act on a non-reassuring fetal heart tracing. 

Resources:

AAP, ACOG (2017). Guidelines for Perinatal Care. 8^th edition.

AWHONN (2021). Perinatal Nursing, 5^th edition.

Miller et al., (2022). Pocket Guide to Fetal Monitoring, A Multidisciplinary Approach. 9^th edition.

P.S. COMMENT AND SHARE:  What do you find to be the most challenging aspect of reviewing birth injury cases with a case theme related to fetal monitoring?

Barber Medical legal Nurse Consulting, LLC is available to support your efforts in making sense of the maternal labor records, while educating your team on fetal heart rate strip interpretation.  

Email: Contact@barbermedicallegalnurse.com.