Electronic Fetal Monitoring: An Update James Paul Ching Maganito, DO, MPH, MHA, CHES Obstetrics and Gynecology Yakima Valley Farm Workers Clinic Yakima Valley Memorial Hospital

Objective Refamiliarize ourselves with the recent ACOG practice bulletin guidelines, July 2009 Reemphasize definition to apply to clinical practice and documentation

Background FHR monitoring Original research started in the 1960’s Original rationale – screening test for asphyxia to prevent neurologic damage / fetal death Original research started in the 1960’s Study done on term pregnancy noted fetal asphyxia of unknown origin in 63% of the research sample (1) (1) Low JA, et al. The prediction and preention of intrapartum fetal asphyxia in term pregnancies. Am J Obstet Gynecol 2001; 184: 724-30

Guidelines for Nomenclature and Interpretation of Electronic Fetal Heart Rate Monitoring 2008 Eunice Kennedy Shriver National Institute of Child Health and Human Development American College of Obstetricians and Gynecologist Workshop focused on FHR monitoring Three goals To review and update the definitions for FHR pattern categorization from the prior workshop To assess existing classification systems for interpreting specific FHR patterns and make recommendations about a system for use in the United States To make recommendations for research priorities for EFM

True or False With regards to uterine contraction, the term hyperstimulation and hypercontractility is still used today and should be adopted and documented?

Uterine Contractions Definition Uterine contractions are quantified as the number of contractions present in a 10 minute window, average over a 30 minute period Documentation should include: frequency, duration, intensity, relaxation time Terminologies Normal: < 5 Ctx in 10min avg over 30min window Tachysystole: > 5 Ctx in 10min avg over 30min window Always qualified as to the presence or absence of associated FHR decelerations Applies to both spontaneous and stimulated labor

True or False? FHR baseline should be document as a range in order to avoid any confusion and give the team a better idea of the characteristic of the baseline?

Baseline FHR rounded to increments of 5bpm during a 10min segment, for at least 2mins, excluding Periodic or episodic changes Periods of marked FHR variability Segments of baseline that differ by more than 25bpm Normal: 110-160bpm Tachycardia: > 160 bpm Bradycardia: < 110bpm

True or False Variability should be described and documented as “no,” “good,” or “severe” as well as in terms of short-term versus long-term variability?

Baseline Variability Absent: undetectable Minimal: < 5bpm Moderate: 6-25bpm Marked: > 25 bpm

Accelerations Abrupt increase (onset to peak is < 30secs) > 32 wk GA, > 15bpm above BL > 15secs but less than 2 mins from onset to return < 32 wks, > 10bpm above BL > 10secs but less than 2mins from onset to return Prolonged accelerations last 2mins or more but less than 10mins > 10 mins is a baseline change

True or False Decelerations are described and documented as persistent, repetitive, or rare? Decelerations should be described as: Periodic: associated w/ uterine contractions Episodic: no association w/ uterine contractions Recurrent: repetitive

Decelerations Early Variable Late Prolonged Sinusoidal Gradual decrease, nadir = peak of ctx Variable Abrupt decrease, > 15 bpm lasting 15 secs but less than 2 mins Late Gradual decrease, nadir = after peak of ctx Prolonged > 15bpm, lasting > 2 mins but less than 10 mins Sinusoidal Smooth, sine wave, cycle frequency of 3-5 per min persisting 20mins or more

Classification of FHR Tracing Category I Category II Catergory III

Classification of FHR Tracings Category I BL: 110-160bpm BL FHR variability: moderate Accelerations: present Early Decels: present or absent Late or variable decels: absent Monitor Routinely No Specific Actions required

Classsification of FHR Tracing Category II BL: Bradycardia not accompanied by absent variability Tachycardia BL Variability Minimal or marked variability Absent with no recurrent decels Accelerations Absence of induced acceleration after fetal stimulation Periodic / Episodic decels Recurrent variable decels Prolonged decels Recurrent later decels Perform Ancillary Test to ensure fetal well being or intrauterine resuscitative measures may be used

Classification of FHR Tracing Category III BL: Absent with recurrent late/variable decels or bradycardia Sinusoidal pattern Prompt evaluation Depending on clinical scenario, expeditiously resolve abnormal FHR pattern by intrauterine resuscitative efforts IF NOT resolved – delivery should be undertaken

Guidelines for Review of Electronic FHR Monitoring Pt w/o complications First stage: q 30mins Second stage: q 15mins Pt w/ complications First stage: q 15mins Second stage: q 5mins

Efficacy of FHR monitoring INCREASED overall cesarean section delivery rate INCREASED operative vaginal delivery – vacuum and forcep Did NOT reduce cerebral palsy risk False positive rate is > 99% in predicting cerebral palsy Rationale: 70% of CP occurs before onset of labor & only 4% can be attributed to intrapartum events Reduced risk of neonatal seizures

Poor interobserver and intraobserver variability The ACOG guidelines highlight a case in which four obstetricians examined 50 FHR tracings; they agreed in only 22% of the cases. Two months later, these four physicians reevaluated the same 50 FHR tracings, and they changed their interpretations on nearly one out of every five tracings. Foreknowledge of neonatal outcome – alters the reviewer’s impressions of FHR tracings – thus not reliable.

Medication Effects on FHR Narcotics 75mg meperidine (Demerol) = 10mg morphine = 0.1 fentanyl = 10mg nalbuphine (nubain) Decrease variability, decrease frequency of accels Butorphanol (Stadol) Transient sinusoidal pattern Corticosteroid Betamethasone: decrease variability – returns to normal by fourth to 7th day post treatment Dexamethasone: no change MgSO4 Decreased variability with early gestational age Mg level did not affect variability Terbutaline Increase baseline FHR and incidence of fetal tachycardia

Ancillary Test to Aid Management of Category II and III Fetal Scalp Sampling Consider with Category III – difficult b/c of decrease in physician experience, difficulty, processing sample Allis Clamp Scalp Stimulation Vibroacoustic Stimulation Digital Scalp Stimulation

Intrauterine Resuscitation Discontinuation of labor stimulating agent Cervical exam Determine umbilical cord prolapse Rapid cervical dilation Descent of the fetal head Change maternal position Monitoring maternal blood pressure level (Hypotension) If secondary to regional anesthetic, volume expansion or IV ephedrine or both Assessment of pt for uterine tachysystole Supplemental oxygen for indeterminate or abnormal patterns There is no data on the efficacy or safety of this therapy Tocolytic agent If position and oxygenation does not change FHR pattern Although tocolytic therapy appears to reduce the number of FHR abnormalities, there is insufficient evidence to recommend it. Amnioinfusion Recurrent variable decels Decrease rate of decel, decrease hospitalization time of pt and newborn

Conclusion Baseline – multiple of 5 Variability – Absent, Minimal, Moderate, Marked Accels – no asphyxia Decels: Early, Variable, Late – Periodic, Episodic, Recurrent (Recurrent periodic/episodic) If in category II and III – physician should be present to evaluate the pt and fetus

Lastly… Computer vs “expert” human visualization, evaluation, and interpretation of electronic fetal heart tracing has been shown to have no statistical difference.

Reference GE: Electronic Fetal Heart Monitoring: Research Guidelines for Interpretation ACOG Practice Bulletin. Intrapartum Fetal Heart Rate Monitoring: Nomenclature, Interpretation, and General Management Principles. Number 106, July 2009 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines. Obstet Gynecol 2008; 112:661-6