Summary DYSTOCIA Williams Obstetrics 25th Chapter 23

Arises from 3 categories (“3 Ps”)
DYSTOCIA 1. Uterine Dysfunction (Power)
2. Fetal Abnormalities (Passenger)
Williams Obstetrics 25th 3. Structural Changes (Passage)
Chapter 23 **Some clinicians acknowledge a 4th P - PSYCHE of the
mother
OUTLINE
DYSTOCIA ............................................................................................. 1 MECHANISMS OF DYSTOCIA
MECHANISMS OF DYSTOCIA ............................................................. 1
ABNORMALITIES OF THE EXPULSIVE FORCES .................................. 1  Uterine Dysfunction
TYPES OF UTERINE DYSFUNCTIONS ................................................ 1  Fetopelvic Proportion
LABOR DISORDERS............................................................................ 2
MATERNAL PUSHING EFFORTS......................................................... 2
FETAL STATION AT LABOR ONSET.................................................... 2 ABNORMALITIES OF THE EXPULSIVE FORCES
RISKS FOR UTERINE DYSFUNCTION................................................. 2  Greatest at the fundus (fundal dominance) and onset of
PREMATURELY RUPTURED MEMBRANES AT TERM .......................... 2 contractions are from fundus, mid zone, and lower uterine
PRECIPITOUS LABOR AND DELIVERY................................................. 2
segments.
FETOPELVIC DISPROPORTION ............................................................ 2
PELVIC CAPACITY .............................................................................. 2  Monitoring of uterine contractions, you are going to palpate
FETAL BODY AND HEAD SIZE ............................................................ 3 the fundus, where the uterine contractions will start.
FETAL PRESENTATIONS .................................................................... 3
SHOULDER DYSTOCIA ......................................................................... 5
DEFINITION/ETIOLOGY....................................................................... 5
TYPES OF UTERINE DYSFUNCTIONS
RISK FACTORS ................................................................................... 6 1. Hypotonic
SHOULDER DYSTOCIA DRILL............................................................. 6 2. Hypertonic
BREECH DELIVERY............................................................................... 7
CLASSIFICATION ................................................................................ 7
FORCEPS DELIVERY............................................................................. 7 4. Lower limit of contraction pressure required to dilate
VACCUM EXTRACTION ......................................................................... 8
the cervix
A. 5mmHg
DYSTOCIA B. 10mmHg
 Difficult labor C. 15mmHg
 Slow labor progress D. 20mmHg
 Other terms:
o Cephalopelvic disproportion
o Failure to progress

1. The Most common cause of Obstructed Labor
A. Pelvic Contracture
B. Malposition
C. Malpresentation
D. Failure to Progress
2. Factors influencing progress of labor are
A. Uterine Contractions
B. Cervical Resistance
C. Pressure exerted by the presenting part
D. All of the above
3. Fetopelvic proportion becomes apparent during Measuring Uterine Contraction
A. First Stage  Palpation:
B. Second Stage o UC <20 seconds = mild
C. Active Stage o UC 20-40 seconds = moderate
D. Latent Phase o UC >40 seconds = strong
 Montevideo unit
o Check for the 10-minute period
o Get how many contractions are there for the span of 10
minutes
o Subtract the baseline from the peak then add all the
pressures from the contractions

5. Hypotonic Uterine Dysfunction is characterized by
A. No basal hypertonus
B. Normal gradient pattern
C. Slow dilatation of the cervix
D. All of the above
6. Hypertonic Uterine Dysfunction
A. Basa tone is elevated
B. Pressure gradient is distorted
C. There is still dilatation of cervix
D. All of the above

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, LABOR DISORDERS RISKS FOR UTERINE DYSFUNCTION
 Neuraxial analgesia can slow labor and has been associated
with lengthening both first and second stages of labor and
slowing the rate of fetal descent.
 Chorioamnionitis is associated with prolonged labor, and
some clinicians have suggested that this maternal
intrapartum infection itself contributes to abnormal uterine
activity.
 PROM (premature rupture of membranes)

PREMATURELY RUPTURED MEMBRANES AT TERM
 Membrane rupture at term without spontaneous uterine
contractions complicates approximately 8 percent of
**Other Criteria: pregnancies.
 Completed Latent Phase >4cm  Labor stimulation initiated if contractions did not begin after 6
 Uterine contraction of 200 Montevideo units in 10 minutes. to 12 hours.
 In those with membranes ruptured >18 hours, antibiotics are
instituted for group B streptococcal infection prophylaxis
7. A G1, 42 weeks, on her 2nd hospital day showed
slow but progressive 1st stage Labor. Management PRECIPITOUS LABOR AND DELIVERY
option now that the patient is at 5cm cervical dilation and  Terminate in expulsion of the fetus in <3 hours of labor
intact BOW and with normal vital signs and FHT.  Brought about by:
A. Bed Rest o Low resistance of the soft parts of the birth canal
B. Cesarean Delivery o Absence of labor sensation
C. Oxytocin
D. Send patient home huhu
FETOPELVIC DISPROPORTION
PELVIC CAPACITY
OB Care Consensus Committee
1. Prolonged latent phase is not an indication for cesarean CONTRACTED INLET
delivery  Important diameters:
2. Protraction disorder managed with observation, o True conjugate
assessment of uterine activity and stimulation of o Obstetrical conjugate
contractions as needed o Diagonal conjugate (measurable)
3. Cervical dilatation threshold for active labor = 6 cm
4. Cesarean delivery for active phase arrest “should be 8. What is the average Biparietal Diameter?
reserved for women at or beyond 6 cm of dilatation with A. 9.5 cm
ruptured membranes who fail to progress despite 4 hours B. 10.5 cm
C. 11.5 cm
of adequate uterine activity or at least 6 hours of oxytocin
D. 12. 5 cm
administration with inadequate contractions and no AP diameter (which is the obstetrical conjugate is commonly
cervical change” approximated by manually measuring the diagonal conjugate
which is approximately 1.5 cm greater)
Concern of the OCCC: no focus on neonatal safety 9. Inlet contraction usually is defined as a diagonal conjugate
Second-labor disorders less than
 Nulliparas second stage duration is 2 hours, +1 hour if with A. 12.5 cm
regional analgesia; allowed to push for 3 hours B. 11.5 cm
 Multiparas second stage duration 1 hour, +1 hour if with C. 10.5 cm
regional analgesia; allowed to push for 2 hours D. 9.5 cm
10. Explain why early spontaneous rupture of membrane
occur more likely in contracted pelvic inlet?
MATERNAL PUSHING EFFORTS  The head is arrested in the pelvic inlet, the entire
force exerted by the uterus acts directly on the
 “Bear down” or “push” portion of the membranes that contact the dilating
 Contraction + pain will urge the patient to push, but cervix.
sometimes the extreme pain will prompt the patient not to
push anymore CONTRACTED MIDPELVIS
 Landmark for midpelvis: ischial spine (bispinous diameter
FETAL STATION AT LABOR ONSET which is 10 cm)
 Transverse diameter of the ischial spine: 10.5 cm
 Station is at 0, 5% CS rate
 Anteroposterior (lower border of the symphysis pubis to S4-
 Station is -1, -2, -3, 14% CS rate S5): 11.5 cm
 Risk for CS is higher if the station is above 0  Posterior sagittal (midpoint of the interspinous line to the
same point on the sacrum): 5 cm
 Contracted mid pelvis: sum of interspinous and posterior
sagittal diameter is less than or equal to 13.5 cm




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