Lecture 18: Dysf. Labor Uterine Contractility and Dystocia Flashcards
During labor, 2 distinct segments of the uterus are formed, what is the function of each?
- Upper segment: actively contracts and retracts to expel fetus
- Lower segment: becomes thinner and passive
The active phase of the 1st stage of labor starts when the cervix is dilated how far?
6 cm
What are the normal limits of the latent phase for nulliparous and multiparous women (hours)?
- Nulliparous = up to 20 hours
- Multiparous = up to 14 hours
In general how are abnormalities of the latent phase managed?
Therapeutic rest (sleep) + Morphine
What are the normal limits of the active phase for cervical dilation (cm/hr) in nulliparous vs. multiparous woman?
- Nulliparous = 1.2 cm/hr
- Multiparous = 1.5 cm/hr
Cervical dilation or fetal descent of less than the norm during the active phase constittutes what type of disorder?
Protraction
What are the normal limits of the active phase for fetal descent (cm/hr) in nulliparous vs. multiparous woman?
- Nulliparous = 1 cm/hr
- Multiparous = 2 cm/hr
How long must no change in cervical dilation and/or fetal descent occur for it to be considered arrest?
- 2 hours or more w/ no cervical dilation
- 1 hour w/ no change in descent/station
Dystocia or “difficult labor” results from abnormalities of the three P’s, which are?
- Power = uterine contractions or maternal expulsive forces
- Passenger = position, size, or presentation of the fetus
- Passage = maternal pelvic bone contractures
The diagnosis of dystocia should not be made before what?
An adequate trial of labor has been tried
At which contraction rate and/or intensity should you consider augmentation of labor?
Contractions <3 in 10 minutes and/or intensity <25 mmHg
ACOG recommends oxytocin in protraction and arrest disordrs after assessing what 4 things?
- Maternal pelvis
- Fetal position
- Station
- Maternal and fetal staus
Placing an IUPC to assess “power” requires rupture of membranes, what 2 situations would you NOT want to do this?
- If the station is really high
- Babies head is ballotable (floating upward) upon palpation
Minimal effective uterine activity is defined by how many contractions in 10 minutes with an average intensity of how much?
3 contractions in a 10-minute period averaging 25 mmHg above baseline
Before proceeding to a C-section should document adequate contractions for at least how long?
At least 4 hours
Nulliparous women who present in labor with an unegaged fetal head indicates an increased likelihood of what?
Cephalopelvic disproportion (CPD)
Which diameter of the fetal head becomes the presenting diameter during transverse arrest of descent?
Occipitofrontal diameter which is 11 cm
What is appropriate management of persistent occipitotransverse position if pelvis is adequate, infant is not macrosomic and contractions are inadequate?
- Start oxytocin
- Rotation: manually or Keilland forceps
The course of labor if fetal head is in OP position is usually normal, but may see what 2 abnormalities?
- The 2nd stage may be prolonged
- Assoc. w/ considerably MORE back discomfort***
What is appropriate management of persistent OP fetal head position?
- Observation if labor continues to be progressive and FHR is normal
- Can use vacuum or forceps (operational delivery)
Most common cause of fetal ascites leading to dystocia is what?
Immune hydrops - Rh isoimmunization
What are the fetal risks associated with macrosomia during delivery?
- Shoulder dystocia
- Fracture of clavicle
- Damage to nerves of brachial plexus: especially C5-C6 (Erb’s palsy)
Most common brachial plexus injury during birth is what?
- Erb-Duschenne
- Upper arm palsy (C5-C6)
Which brachial plexus injury is more common with shoulder dystocia?
Klumpke’s palsy (C8 and T1); but Erb’s is still most common
What is first line and last resort managment of Shoulder Dystocia; what can be done after?
- McRobert’s Maneuver —> Hyerflexion and ABduction of maternal hips
- Suprapubic pressure
- Zavanelli maneuver is last resort –> will need C-section delivery
