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Flashcards in 4. Normal Labor and Delivery Deck (17):

Obstetric Exam:

Fetal lie


Fetal presentation

Fetal lie: transverse vs. longitudinal within the uterus


Fetal presentation: breech vs. vertex (cephalic)


Rupture of Membranes:




How to dx? (3 tests)

PROM = premature rupture of membranes... occurs more than 18 hrs before labor (puts both mom and fetus at inc. risk for infection)


PPROM = preterm, premature rupture of membranes (before 37 wks)


Dx: pool, nitrazine, and fern tests

  • pool test = + if there is a collection of fluid in the vagina (speculum exam)
  • nitrazine test = vaginal secretions are normally acidic, while amniotic fluid is alkaline... thus, when amniotic fluid is placed on nitrazine paper, paper should immediately turn blue
  • fern test = estrogens in amniotic fluid cause crystallization of the salts in the amniotic fluid when it dries... under low power, crystals resembles blades of a fern


Rupture of membranes:


What will you see on U/S?





Amnisure = rapid test to identify placental alpha-microglobulin-1 via immunoassay, which appears to have a higher sensitivity and specificity than conventional tests for PROM


Cervical Exam:


5 aspects of exam?

  • Purpose: determine whether patient is in labor, phase of labor, how labor is progressing
  • 5 components (Bishop Score): 
    • Dilation
    • Effacement
    • Fetal station (the relation of the fetal head to ischial spines)
    • Cervical position 
    • Consistency of cervix


Bishop shore > 8 is consistent with a cervix favorable for both spontaneous labor and induced labor.


How to induce labor? (4) = Ripening and dilation 


How to formally begin labor induction?



  • Prostaglandins (Cervidil = PGE2, Misoprostol = PGE1... "ripens" cervix)
  • Oxytocic agents
  • Mechanical dilation of cervix
  • Artificial ROM 


Formally begin = oxytocin (Pitocin)

  • Given continuously via IV drip b/c it is rapidly metabolized



Maternal and obstetric contraindications for the use of prostaglandins

Maternal: Asthma, glaucoma

Obstetric: prior C/S, nonreassuring fetal testing


What is a reactive tracing?

At least two accelerations of at least 15 bpm over the baseline that last for at least 15 seconds within 20 minutes 


What are the three types of decelerations?

  1. Early: begin and end approx at same time as contractions
    1. Result of increased vagal tone 2/2 head compression during contraction
  2. Variable: can occur at any time 
    1. Result of umbilical cord compression
  3. Late: begin at peak of contraction and slowly return to baseline after contraction has finished
    1. Result of uteroplacental insufficiency = MOST WORRISOME TYPE :(
    2. May degrade into bradycardias as labor progresses


When would you use a fetal scalp electrode?



1) In the case of repetitive decelerations or

2) in fetuses who were difficult to trace externally with Doppler



hx of maternal hepatitis, HIV, or fetal thrombocytopenia


Fetal Heart Rate Tracings


Category I, III

  • Category I:
    • Normal fetal HR tracing
    • Normal baseline
    • Moderate variability 
    • No variable or late decelerations
  • Category III
    • Abnormal fetal HR tracing
    • Absent fetal heart variability 
    • Recurrent late or variable decelerations or bradycardia
    • ** other category III tracing is a sinusoidal pattern consistent with fetal anemia


Cardinal Movements of Labor

  • Engagement
  • Descent
  • Flexion
  • Internal rotation
  • Extension
  • External rotation


When the fetal presenting part enters the pelvis, it is said to have undergone engagement. The head will then undergo descent into the pelvis, followed by flexion, which allows the smallest diameter to present to the pelvis. With descent into the midpelvis, the fetal vertex undergoes internal rotation from an OT position so that the sagittal suture is parallel to the AP diameter of the pelvis, commonly to the occiput anterior position. As the vertex passes beneath and beyond the pubic symphysis, it will extend to deliver. Once the head delivers, external rotation occurs and the shoulders may be delivered.


Stages of Labor:


Stage I

Onset of labor until complete dilation of cervix has occurred


  • Length: Avg first stage of labor lasts approx 10-12 hours in nulli and 6-8 hours in multip
  • Phases: Latent and Active
    • ​Latent = generally ranges from onset of labor until 3 or 4 cm dilation (slow cervical change)
    • Active = extends until greater than 9 cm of dilation and is defined by the period of time when slope of cervical change against time increases
      • at least 1.0 cm/hour of dilation in nulli
      • at least 1.2 cm/hr of dilation in multip
      • 3 P's = power, passenger, pelvis
        • Cephalopelvic disproportion (CPD) if "passenger" is too large for "pelvis"


If you see repetitive late decels, bradycardias, loss of variability... next step in mgmt? 

  • Place on face mask O2
  • Turn onto her L side to decrease IVC compression and increase uterine perfusion
  • if being used, d/c oxytocin immediately until tracing resumes a reassuring pattern


Stage 3 of Labor: 


What are the 3 signs of placental separation?

Cord lengthening

Gush of blood

Uterine fundal rebound as placenta detaches from uterine wall




Retained placenta

When the placenta does not deliver within 30 minutes after the infant


Retained placenta is common in preterm deliveries, particularly previable deliveries. However, it is also a sign of placenta accreta, where the placenta has invaded into or beyond the endometrial stroma


Indications for Cesarean Section








What is the greatest risk during a trial of labor after cesarean (TOLAC)?


What are the signs that this risk has occurred?

Rupture of the prior uterine scar (occurs approximately 0.5% to 1.0% of the time)


Signs of rupture:

  • abdominal pain,
  • FHR decelerations or bradycardia,
  • sudden decrease of pressure on an IUPC,
  • maternal sensation of a "pop"