21: Dysfunctional Labor

Question 1

Definition of labor

Answer 1

Presence of regular uterine contractions of sufficient intensity, frequency, and duration to bring about demonstrable effacement and dilation of the cervix

Question 2

First stage of Labor

Answer 2

Onset of contractions to full dilation of cervix

Question 3

Second stage of Labor

Answer 3

Full dilation of cervix to delivery of infant

Question 4

Third stage of Labor

Answer 4

Delivery of infant to delivery of placenta

Question 5

Latent phase (of first stage) of Labor

Answer 5

Cervical softening/effacement occurs with minimal dilation (less than 4 cm)

Question 6

Active phase (of first stage) of Labor

Answer 6

Starts when cervix dilated to 4 cm, includes descent of presenting fetal part

Question 7

What are the minimal cervical dilation rates for 1. nulliparous and 2. multiparous women?

Answer 7

1. 1.2 cm/hr

2. 1.5 cm/hr

Question 8

What are the minimal rates of descent for 1. nulliparous and 2. multiparous women?

Answer 8

1. 1.0 cm/hr

2. 2.0 cm/hr

Question 9

Protraction disorders of labor

Answer 9

Delayed/prolonged stages

Question 10

Arrest disorders of labor

Answer 10

Complete failure to progress

Question 11

The 3 P’s influencing abnormal/difficult labor

Answer 11

Power - contraction/maternal expulsive force
Passenger - position, size, presentation of fetus
Passage - maternal pelvic bone contractures

Question 12

Augmentation of labor

Answer 12

Stimulation of uterine contraction when spontaneous contractions have failed to result in progressive cervical dilation or descent of the fetus

Question 13

When should augmentation be considered?

Answer 13

If contractions are less than 3 in 10 minute period or if intensity is less than 25mmHg

Question 14

What is recommended by ACOG for protraction and arrest disorders?

Answer 14

Oxytocin

Question 15

Benefits to rupture of membranes

Answer 15

augments labor, allows assessment of meconium status

Question 16

Risks to rupture of membranes

Answer 16

cord prolapse, chorioamnionitis

Question 17

Minimal effective uterine activity

Answer 17

3 contractions in a 10 minute period averaging 25 mmHg above baseline

Question 18

MVU

Answer 18

Montevideo units - calculated by measuring peaks of contractions in mmHg in a 10 minute period

Question 19

How many MVU needed for how long to measure effective activity?

Answer 19

> 200 MVU for at least 2 hours. Need to document for 4 hours before proceeding to C-section

Question 20

Pitocin

Answer 20

Only FDA approved medicine for labor stimulation; stimulates uterine contractions

Question 21

Cephalopelvic disproportion (CPD)

Answer 21

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

Question 22

Normal fetal presentation in laboring patient

Answer 22

Vertex occiput anterior (OA)

Question 23

Transverse arrest of descent

Answer 23

Persistent OT position with arrest of descent for a period of 1 hour or more

Question 24

Which forceps are used specifically for rotation of baby in persistent OT position?

Answer 24

Keilland forceps

Question 25

Macrosomia

Answer 25

Defined as fetus weighing >4500g when mother has Gestational Diabetes; >5000g in all others

Question 26

Risks associated with macrosomia

Answer 26

Shoulder dystocia, fracture of clavicle, damage to brachial plexus

Question 27

Most common brachial plexus injury

Answer 27

Erb-Duschenne - upper arm palsy; injury to C5, C6

Question 28

Turtle sign

Answer 28

Retraction of delivered fetal head against the maternal perineum

Question 29

McRobert’s maneuver and Suprapubic pressure

Answer 29

Used to manage shoulder dystocia; McRobert’s: hyperflexion and abduction of maternal hips; suprapubic pressure may dislodge anterior shoulder
do NOT apply fundal pressure

Question 30

Zavanelli maneuver

Answer 30

Reverse cardinal movements for cephalic replacment; last resort