Dysfunctional Labor

Question 1

physiologic changes of the uterus in labor

Answer 1

upper segment contracts and retracts to expel the fetus

lower segment along the cervix becomes thinner and passive

Question 2

physiologic changes of the cervix in labor

Answer 2

becomes soft, pliable and dilated structure

result of collagenolysis, increased hyaluronic acid, and decreased dermatan sulfate

Question 3

abnormalities of active labor

Answer 3

protraction - slower than normal

arrest - complete cessation of progress

Question 4

what does an arrest in the latent phase imply?

Answer 4

true labor has not begun

Question 5

what is considered a prolonged latent phase?

Answer 5

> 20 hrs for primiparous

> 14 hrs for multiparous

Question 6

causes of prolonged latent phase

Answer 6

lack of substantial cervical change
excessive use of sedatives or analgesics
fetal malposition

Question 7

prolonged latent phase management

Answer 7

sleep - true vs false labor

morphine - 62-85% will progress to active phase

Question 8

protraction disorder

Answer 8

protraction of dilation - dilation less than norm

protraction of descent - descent less than norm

Question 9

if 2 or more hours elapse with no cervical dilation, what has occured?

Answer 9

arrest of dilation

Question 10

if no change in descent has occured within 1 hour what is the dx?

Answer 10

arrest of descent/station

Question 11

what is the risk associated with active phase abnormalities?

Answer 11

increased risk of perinatal mortality

Question 12

etiology of active phase abnormalities

Answer 12

inadequate uterine activity
cephalopelvic disproportion
fetal malposition
anesthesia

Question 13

dystocia

Answer 13

difficult labor

Question 14

3 P’s of dystocia

Answer 14

power = uterine contractions or expulsive forces
passenger = position, size or presentation of fetus
passage = pelvic bone contractures

Question 15

what needs to occur before dystocia is dx?

Answer 15

an adequate trial of labor has been attempted

Question 16

when should augmentation be considered?

Answer 16

if contractions are less than 3 in 10 min period or the intensity is less than 25 mmHg

Question 17

what needs to be assessed prior to giving oxytocin in protraction and arrest disorders?

Answer 17

maternal pelvis
fetal position
station
maternal and fetal status

Question 18

how can “power” be assessed?

Answer 18

intrauterine pressure catheter (IUPC)

requires membranes to be ruptured

Question 19

what are montevideo units (MVU)?

Answer 19

measure the peaks of contractions in mmHg in a 10 minute period

normal = > 200 MVU for at least 2 hrs

Question 20

what needs to be documented before proceeding to C-section?

Answer 20

adequate contractions for at least 4 hours

Question 21

MOA of pitocin

Answer 21

increased intracellular CA which results in increase in actin/myosin activity

Question 22

cephalopelvic disproportion (CPD)

Answer 22

disparity between the size of the maternal pelvis and the fetal head that precludes vaginal delivery

Question 23

what indicates an increased likelihood of CPD?

Answer 23

primiparous woman who presents in labor with an unengaged head

Question 24

what is considered an abnormal fetal presentation?

Answer 24

anything other than vertex occiput anterior presentation

Question 25

abnormal fetal structures that can cause dystocia

Answer 25

macrosomia
shoulder dystocia
fetal anomalies

Question 26

persistent occipitotransverse (OT) position

Answer 26

occurs when the head fails to rotate and flex into the OA position

may be caused by CPD

Question 27

transverse arrest of descent

Answer 27

persistent OT position with arrest of descent for ≥ 1 hr

Question 28

management of persistent OT position

Answer 28

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

Question 29

what is the normal outcome of persistent occipitoposterior (OP) position?

Answer 29

labor usually proceeds without issue
second stage may be prolonged
associated with more back discomfort

Question 30

management of persistent OP position

Answer 30

observation and delivery
OR
operative vaginal delivery with vacuum or forceps

Question 31

macrosomia

Answer 31

fetus weighing 4500 g (10 lbs!!!)

Question 32

large for gestational age

Answer 32

birth weight equal to or greater than the 90% for a given gestational age

Question 33

fetal abnormalities that may cause dystocia

Answer 33

hydrocephalus
fetal ascites
immune hydrops
conjoined twins
locked twins

Question 34

risk factors that cause macrosomia

Answer 34

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

Question 35

risk factors associated with macrosomia

Answer 35

maternal morbidity due to post-partum hemorrhage

fetal morbidity and mortality due to fracture of clavicle, shoulder dystocia, and brachial plexus injury

Question 36

what is recommended course of action for macrosomia?

Answer 36

prophylactic C-section

Question 37

antepartum risk factors for shoulder dystocia

Answer 37

fetal macrosomia
maternal diabetes
obesity
post-term gestation
short stature
hx of macrosomic birth
hx of shoulder dystocia

Question 38

labor risk factors for shoulder dystocia

Answer 38

labor induction
epidural
prolonged labor
operative vaginal deliveries

Question 39

possible fetal outcomes of shoulder dystocia

Answer 39

brachial plexus injuries
fractured clavicle or humerus
hypoxic-ischemic encephalopathy
death

Question 40

management of shoulder dystocia

Answer 40

McRobert’s maneuver - hyperflexion and abduction of maternal hips

suprapubic pressure
fetal rotational maneuvers

proctoepisotomy

Zavanelli maneuver - cephalic replacement *last resort

Question 41

is shoulder dystocia an obstetric emergency?

Answer 41

YES! call for help - anesthesia and NICU