Safe Deliveries Project
Management of Indeterminate
(Category II) Intrapartum Fetal
Heart Rate Tracings
Kathleen Simpson, PhD, RNC
November 19, 2013
Presented at Washington State Hospital Association Safe Table 11/19/2013
Presented at Washington State Hospital Association Safe Table 11/19/2013
Assuring Fetal Wellbeing
• Supporting a woman in giving birth vaginally
within the upper normal limits of labor
duration must be in the context of a well fetus
• Assessment of fetal status should be
considered relative to the likelihood and
timing of vaginal birth
Presented at Washington State Hospital Association Safe Table 11/19/2013
Labor Progress: Nulliparous Women
Spontaneous (Hours)
Induction (Hours)
Augmented (Hours)
(5th / 95th percentiles)
(5th / 95th percentiles)
(5th / 95th percentiles)
3-10
4.2
(1.3, 13.1)
6.9
(2.0, 24.9)
6.6
(2.0, 23.6)
3-4
0.4
(0.1, 2.3)
1.4
(0.2, 8.1)
1.2
(0.2, 6.8)
4-5
0.5
(0.1, 2.7)
1.3
(.02, 6.8)
1.4
(.03, 7.6)
5-6
0.4
(0.06, 2.7)
0.6
(0.1, 4.3)
0.7
(0.1, 4.9)
6-7
0.3
(0.03, 2.1)
0.4
(0.05, 2.8)
0.5
(0.06, 3.9)
7-8
0.3
(0.04, 1.7)
0.2
(0.03, 1.5)
0.3
(0.05, 2.2)
8-9
0.2
(0.03, 1.3)
0.2
(0.03, 1.3)
0.3
(0.03, 2.0)
9-10
0.3
(0.04, 1.8)
0.3
(0.04, 1.9)
0.3
(0.05, 2.4)
cm
Harper et al., 2012 Normal progress of induced labor.
Obstetrics and Gynecology 119(6),1113–8
Presented at Washington State Hospital Association Safe Table 11/19/2013
Assuring Fetal Wellbeing
• Birth of the fetus, when possible,
prior to the development of
damaging degrees of hypoxia/
acidemia
Presented at Washington State Hospital Association Safe Table 11/19/2013
Presented at Washington State Hospital Association Safe Table 11/19/2013
Fetal Status Fluctuations during Labor
• Most fetuses (84%) will demonstrate FHR pattern
characteristics that are both normal (category I) and
indeterminate (category II) over the course of labor
• Abnormal (category III) FHR patterns are rare (0.1%)
• On average, the duration of category I is about 78% of
labor, category II; 22% and category III; 0.004%
• Ideally, if the FHR pattern is category II, there is
moderate variability and/or accelerations to support
the presumption of a non-acidotic fetus
Jackson et al. (2011). Frequency of fetal heart rate categories and
short-term neonatal outcome. Obstet Gynecol. 118(4):803–808.
Presented at Washington State Hospital Association Safe Table 11/19/2013
Frequency of FHR Categories/
Short-Term Neonatal Outcome
• Babies of women whose last 2 hrs were exclusively
normal (category I) did well
• only 0.6% had 5-min Apgar scores less than 7
• 0.2% had low Apgar scores with NICU admission
• When >75% of last 2 hrs was indeterminate (category II)
• low 5-min Apgar score increased to 1.3% of patients
• low 5-min Apgar score with NICU admission increased to 0.7%
Jackson et al. (2011). Frequency of fetal heart rate categories and
short-term neonatal outcome. Obstet Gynecol. 118(4):803–808.
Presented at Washington State Hospital Association Safe Table 11/19/2013
Indeterminate (Category II)
• Wide range of clinical implications
associated with various types of FHR
patterns within category II
• Imprecise nature of category II as it
relates to fetal wellbeing makes it
challenging / not always useful for clinical
decisions during labor
Presented at Washington State Hospital Association Safe Table 11/19/2013
Indeterminate (Category II)
Presented at Washington State Hospital Association Safe Table 11/19/2013
11
Presented at Washington State Hospital Association Safe Table 11/19/2013
Assumptions/Clarifications
• Marked variability is considered same as
moderate variability
• Significant decelerations are defined as any
of the following:
• Variable decelerations lasting >60 sec and >60 bpm
below baseline.
• Variable decelerations lasting >60 sec and <60 bpm
regardless of baseline.
• Late decelerations of any depth
• Prolonged deceleration
Clark et al., (2013). Intrapartum management of category II fetal heart rate tracings:
Towards standardization of care. Am J Obstet Gynecol;209(2):89–97.
Presented at Washington State Hospital Association Safe Table 11/19/2013
Assumptions/Clarifications
• Application of algorithm may be initially delayed for up
to 30 min while attempts are made to alleviate category
II pattern with conservative therapeutic interventions
(e.g., correction of hypotension, position change,
amnioinfusion, tocolysis, reduction or discontinuation
of oxytocin)
• Once a category II FHR pattern is identified, FHR is
evaluated and algorithm applied q 30 min
• Any significant change in FHR parameters should result
in reapplication of algorithm
Clark et al., (2013). Intrapartum management of category II fetal heart rate tracings:
Towards standardization of care. Am J Obstet Gynecol;209(2):89–97.
Presented at Washington State Hospital Association Safe Table 11/19/2013
Assumptions/Clarifications
• For category II FHR patterns in which
algorithm suggests cesarean birth is
indicated, birth should ideally be
initiated within 30 min of decision
Clark et al., (2013). Intrapartum management of category II fetal heart rate tracings:
Towards standardization of care. Am J Obstet Gynecol;209(2):89–97.
Presented at Washington State Hospital Association Safe Table 11/19/2013
Assumptions/Clarifications
• If at any time tracing reverts to category
I status, or deteriorates for even a short
time to category III status, the algorithm
no longer applies
Clark et al., (2013). Intrapartum management of category II fetal heart rate tracings:
Towards standardization of care. Am J Obstet Gynecol;209(2):89–97.
Presented at Washington State Hospital Association Safe Table 11/19/2013
Moderate variability and accelerations, thus
excluding clinically significant acidemia
• Per algorithm, if labor is progressing normally
in active phase or second stage, careful
observation would be appropriate
• If the fetus is remote from birth, expediting
birth would be appropriate
Presented at Washington State Hospital Association Safe Table 11/19/2013
Moderate variability and accelerations, thus
excluding clinically significant acidemia
• Significant variable decelerations suggest umbilical
cord compression during contraction, which could,
over time, lead to significant acidemia
• Per algorithm, if labor is progressing normally in
active phase or second stage, careful observation
would be appropriate; if the fetus is remote from birth,
expediting birth would be appropriate
Presented at Washington State Hospital Association Safe Table 11/19/2013
Minimal to absent variability without
decelerations, despite regular contractions
• Medication effect has been excluded clinically as part of the
initial period of intrauterine resuscitation attempts
• While the fetus may have experienced prelabor central
nervous system injury, absence of late decelerations
excludes ongoing hypoxia in a neurologically intact fetus
• However, since such fetuses may not tolerate labor without
sudden deterioration and demise, cesarean birth would be
appropriate, per algorithm, if pattern persists for 1 hour
Presented at Washington State Hospital Association Safe Table 11/19/2013
Minimal to absent variability/late decelerations
occurring with >50% of contractions
• Per algorithm, expedited birth is
indicated regardless of labor progress
Presented at Washington State Hospital Association Safe Table 11/19/2013
Summary
• It is reasonable to initiate management of a
category II FHR pattern with an assessment of
variability and accelerations, thus allowing the
clinician to immediately rule out the presence
of clinically significant metabolic acidemia
• For nonacidemic fetuses, the focus then shifts
to assessing the likelihood of developing
significant acidemia prior to birth
Clark et al., (2013). Intrapartum management of category II fetal heart rate tracings:
Towards standardization of care. Am J Obstet Gynecol;209(2):89–97.
Presented at Washington State Hospital Association Safe Table 11/19/2013