Dysfunctional Labor Flashcards
physiologic changes of the uterus in labor
upper segment contracts and retracts to expel the fetus
lower segment along the cervix becomes thinner and passive
physiologic changes of the cervix in labor
becomes soft, pliable and dilated structure
result of collagenolysis, increased hyaluronic acid, and decreased dermatan sulfate
abnormalities of active labor
protraction - slower than normal
arrest - complete cessation of progress
what does an arrest in the latent phase imply?
true labor has not begun
what is considered a prolonged latent phase?
> 20 hrs for primiparous
> 14 hrs for multiparous
causes of prolonged latent phase
lack of substantial cervical change
excessive use of sedatives or analgesics
fetal malposition
prolonged latent phase management
sleep - true vs false labor
morphine - 62-85% will progress to active phase
protraction disorder
protraction of dilation - dilation less than norm
protraction of descent - descent less than norm
if 2 or more hours elapse with no cervical dilation, what has occured?
arrest of dilation
if no change in descent has occured within 1 hour what is the dx?
arrest of descent/station
what is the risk associated with active phase abnormalities?
increased risk of perinatal mortality
etiology of active phase abnormalities
inadequate uterine activity
cephalopelvic disproportion
fetal malposition
anesthesia
dystocia
difficult labor
3 P’s of dystocia
power = uterine contractions or expulsive forces passenger = position, size or presentation of fetus passage = pelvic bone contractures
what needs to occur before dystocia is dx?
an adequate trial of labor has been attempted
when should augmentation be considered?
if contractions are less than 3 in 10 min period or the intensity is less than 25 mmHg
what needs to be assessed prior to giving oxytocin in protraction and arrest disorders?
maternal pelvis
fetal position
station
maternal and fetal status
how can “power” be assessed?
intrauterine pressure catheter (IUPC)
requires membranes to be ruptured
what are montevideo units (MVU)?
measure the peaks of contractions in mmHg in a 10 minute period
normal = > 200 MVU for at least 2 hrs
what needs to be documented before proceeding to C-section?
adequate contractions for at least 4 hours
MOA of pitocin
increased intracellular CA which results in increase in actin/myosin activity
cephalopelvic disproportion (CPD)
disparity between the size of the maternal pelvis and the fetal head that precludes vaginal delivery
what indicates an increased likelihood of CPD?
primiparous woman who presents in labor with an unengaged head
what is considered an abnormal fetal presentation?
anything other than vertex occiput anterior presentation
abnormal fetal structures that can cause dystocia
macrosomia
shoulder dystocia
fetal anomalies
persistent occipitotransverse (OT) position
occurs when the head fails to rotate and flex into the OA position
may be caused by CPD
transverse arrest of descent
persistent OT position with arrest of descent for ≥ 1 hr
management of persistent OT position
if pelvis is adequate, infant is not macrosomic, and contractions are inadequate = start Pitocin and engage rotation of fetus
if pelvis is inadequate or fetus is macrosomic = C-section
what is the normal outcome of persistent occipitoposterior (OP) position?
labor usually proceeds without issue
second stage may be prolonged
associated with more back discomfort
management of persistent OP position
observation and delivery
OR
operative vaginal delivery with vacuum or forceps
macrosomia
fetus weighing 4500 g (10 lbs!!!)
large for gestational age
birth weight equal to or greater than the 90% for a given gestational age
fetal abnormalities that may cause dystocia
hydrocephalus fetal ascites immune hydrops conjoined twins locked twins
risk factors that cause macrosomia
maternal DM hx of macrosomia maternal obesity weight gain during pregnancy multiparity male fetus > 40 wks gestation ethnicity maternal birth weight maternal height maternal age < 17 y/o
risk factors associated with macrosomia
maternal morbidity due to post-partum hemorrhage
fetal morbidity and mortality due to fracture of clavicle, shoulder dystocia, and brachial plexus injury
what is recommended course of action for macrosomia?
prophylactic C-section
antepartum risk factors for shoulder dystocia
fetal macrosomia maternal diabetes obesity post-term gestation short stature hx of macrosomic birth hx of shoulder dystocia
labor risk factors for shoulder dystocia
labor induction
epidural
prolonged labor
operative vaginal deliveries
possible fetal outcomes of shoulder dystocia
brachial plexus injuries
fractured clavicle or humerus
hypoxic-ischemic encephalopathy
death
management of shoulder dystocia
McRobert’s maneuver - hyperflexion and abduction of maternal hips
suprapubic pressure
fetal rotational maneuvers
proctoepisotomy
Zavanelli maneuver - cephalic replacement *last resort
is shoulder dystocia an obstetric emergency?
YES! call for help - anesthesia and NICU
