4: Normal L&D Flashcards
A Bishop score greater than ? is consistent with a cervix favorable for both spontaneous labor and, as it is more commonly used, induced labor.
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five components of the cervical examination
dilation, effacement, fetal station, cervical position, and consistency of the cervix
Prodromal labor or “false labor”
These patients usually present with irregular contractions that vary in duration, intensity, and intervals and yield little or no cervical change.
Labor is induced with ?
prostaglandins, oxytocic agents, mechanical dilation of the cervix, and/or artificial ROM.
A Bishop score of ? or less may lead to a failed induction as often as 50% of the time
what can be used to “ripen” the cervix?
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prostaglandin E2 (PGE2) gel, PGE2 pessary (Cervidil), or PGE1M (misoprostol) or mechanical means
contraindications to PGEs
maternal: asthma, glaucoma
obstetric: prior C section, nonreassuring fetal status
* cannot turn off PGE2 gel: risk of uterine hyperstimulation and tetanic contractions: use a mechanical dilator such as a 30 cc or 60 cc Foley bulb
after amniotomy it is important not to ? in order to avoid cord prolapse
elevate the fetal head from the pelvis
the adequacy of contractions is indirectly assessed by ? and ?
the progress of cervical change
an IUPC
intrauterine pressure catheter (IUPC)
determines the absolute change in pressure during a contraction and thus estimates the strength of contractions
with FHR >160 bpm, what are possible concerns?
fetal distress secondary to infection, hypoxia, or anemia
Any prolonged fetal heart rate deceleration of greater than ? duration with a heart rate less than ? is of concern and requires immediate action.
2 minutes’
90 bpm
FHR variability definitions
absent (less than 3 beats per minute of variation), minimal (3 to 5 beats per minute of variation), moderate (5 to 25 beats per minute of variation), and marked (more than 25 beats per minute of variation)
a tracing can be considered formally reactive if ?
there are at least two accelerations of at least 15 bpm over the baseline that last for at least 15 seconds within 20 minutes.
early decelerations are from
increased vagal tone secondary to head compression during a contraction
Variable decelerations are a result of
umbilical cord compression
Late decelerations are a result of
uteroplacental insufficiency
They may degrade into bradycardias as labor progresses, particularly with stronger contractions.
In the case of repetitive decelerations or in fetuses who are difficult to trace externally with Doppler, a ?is often used.
fetal scalp electrode (FSE)
A small electrode is attached to the fetal scalp that senses the potential differences created by the depolarization of the fetal heart
CIs: maternal hepatitis, HIV or fetal thrombocytopenia
Category I FHR tracing
normal FHR tracing characterized by a normal baseline, moderate variability, and no variable or late decelerations.
Category II FHR tracing
indeterminate FHR tracing; a variety of tracings including those with variable and late decelerations, bradycardia and tachycardia, minimal variability, marked variability, and even absent variability without decelerations.
It is not Tier I and not Tier III, but every other fetal heart tracing.
Category III FHR tracing
abnormal fetal heart rate tracing; those with absent fetal heart variability AND recurrent late or variable decelerations or bradycardia.
the sinusoidal pattern consistent with fetal anemia is also Category III
external tocometer vs IUPC
If it is particularly important to determine the timing or strength of contractions, an IUPC may be used
Montevideo unit
an average of the variation of the intrauterine pressure from the baseline multiplied by the number of contractions in a 10-minute period
-Strength of uterine contractions can be considered adequate with greater than 200 Montevideo units
If a fetal heart rate tracing is nonreassuring, the fetal scalp pH may be obtained to directly assess fetal hypoxia and academia.
levels that are reassuring/nonreassuring?
reassuring when the scalp pH is greater than 7.25, indeterminant when it is between 7.20 and 7.25, and nonreassuring when it is less than 7.20.
The cardinal movements are ?
engagement, descent, flexion, internal rotation, extension, and external rotation (also called restitution or resolution)
first stage of labor ranges
approximately 10 to 12 (6-20 hour total range) hours in a nulli and 6 to 8 hours in a multi (2-12 hrs)
During the active phase, at least ? of dilation is expected in a nulliparous patient and ? in a multiparous patient. This minimal expectation is approximately the fifth percentile of women undergoing labor and the median rates of dilation range from ?
- 0 cm/hour
- 2 cm/hour
2.0 to 3.0 cm/hour
If the “passenger” is too large for the “pelvis,”
cephalopelvic disproportion (CPD)
Stage 2 is considered prolonged if its duration is longer than
nulli: >2 hours, >3 hours if epidural
multi: >1 hour, >2 hours with an epidural (typ.
what to do if nonreassuring fetal status i.e. repetitive late decelerations, bradycardias, and loss of variability
face mask O2, turned on left side to decrease IVC compression and increase uterine perfusion; stop oxytocin until the tracing resumes a reassuring pattern.
what to do if a prolonged deceleration is felt to be the result of uterine hypertonus (a single contraction lasting 2 minutes or longer) or tachysystole (greater than five contractions in a 10-minute period)
give a dose of terbutaline to help relax the uterus
indications for episiotomy
need to speed up delivery, impending/ongoing shoulder dystocia
-not routinely used as there is risk of lacerations increases with episiotomy esp. with medial vs. mediolateral cuts
The conditions necessary for safe application of forceps
full dilation of the cervix, ruptured membranes, engaged head and at least +2 station, absolute knowledge of fetal position, no evidence of CPD, adequate anesthesia, empty bladder, and—most important—an experienced operator.
complications of using vacuum
scalp laceration, cephalohematoma, shoulder dystocia
rare: subgaleal hemorrhage
complications of forceps
lacerations, bruising, facial nerve damage
rare: skull fracture, intracranial damage
stage 3 of labor
delivery of placenta, usually within 5-10 min of infant, up to 30 is within normal limits
give what during stage 3
oxytocin, strengthens uterine contractions to decrease placental delivery time and blood loss
The three signs of placental separation
cord lengthening, a gush of blood, and uterine fundal rebound
-don’t attempt to deliver placental until all these signs are noted
retained placenta is common in ?
what can be done?
preterm/previable deliveries, placenta accreta
D&C
degrees of laceration
1st degree: involves the mucosa or skin.
2nd degree: extend into the perineal body but does not involve the anal sphincter.
3rd degree: extend into or completely through the anal sphincter.
4th degree: occurs if the anal mucosa itself is entered.
what is failure to progress or active phase arrest?
2 hours without cervical change in the setting of adequate uterine contractions in the active phase of labor
-often leads to C section but it is reasonable to wait at least 4 hours for cervical stage in the active phase of labor
most common indications for C section
breech presentation, transverse lie, shoulder presentation, placenta previa, placental abruption, fetal intolerance of labor, nonreassuring fetal status, cord prolapse, prolonged second stage, failed operative vaginal delivery, or active herpes lesions. previous cesarean section is most common indication
Vaginal birth after cesarean (VBAC) can be attempted if the prior hysterotomy was a ?
Kerr (low transverse incision) or Kronig (low vertical incision) without any extensions into the cervix or upper uterine segment
NOT classical hysterectomy or vertical incision through the thick upper segment of the uterine corpus
The greatest risk during a trial of labor after cesarean (TOLAC)
rupture of the prior uterine scar
signs of uterine rupture
abdominal pain, FHR decelerations or bradycardia, sudden decrease of pressure on an IUPC, and maternal sensation of a “pop.”
pain management in labor
first stage: fentanyl, Nubain, Stadol, IM morphine
pudendal block given for
operative vaginal delivery
epidural vs spinal anesthesia
spinal is given in a one-time dose directly into the spinal canal leading to more rapid onset of anesthesia, more common for C sections than vaginal
complications of epidurals and spinal anesthesia
- maternal hypotension secondary to decreased SVR, which can lead to decreased placental perfusion and fetal bradycardia
- more serious: maternal respiratory depression if the anesthetic reaches a level high enough to affect diaphragmatic innervation.
- spinal headache from CSF loss
when is general anesthesia used and what are complications
C section, especially emergent
-maternal aspiration and hypoxia to mother and fetus
Common reasons for an emergent cesarean section
abruption, fetal bradycardia, umbilical cord prolapse, uterine rupture, and hemorrhage from a placenta previa.
Labor can be induced or augmented with
prostaglandins, oxytocin, laminaria, Foley bulb, and artificial ROM.
epidurals lead to a longer ?
second stage of labor, but offers better control during crowning
