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Midwifery Division
Department of OB/GYN
University of North Carolina
School of Medicine
OBJECTIVES
 Define labor and its stages
 Exam of the laboring woman and her fetus
 Review the cardinal movements of labor and birth
 Review Disorders of Labor
 Induction of Labor
 Other labor and delivery issues
Define Labor and its Stages
 Labor: progressive change of the cervix in the setting of
uterine contractions
 Term Labor: > 37 weeks gestation
 Preterm Labor: < 37 weeks gestation
 11% of all US births in 1997
 80% of preterm births between 34 - 36
 Preterm delivery < 35 weeks: 3.5%
weeks
Define Labor and its Stages
 Stages of Labor
 1st stage – onset of labor until full cervical dilitation
 2nd stage – from full dilitation to birth of infant
 3rd stage – from birth of infant until delivery of
placenta
 4th stage – 2 hours after the delivery of placenta
Define labor and its Stages
1st stage and its phases
 Latent phase: onset of contractions
until active phase
 Active phase: 3 cm dilation in
nulliparas; 4 cm dilation in multiparas
to deceleration phase
 Deceleration phase: 8 – 9 cm dilation
to complete dilation
Exam of the Laboring woman and
her Fetus
 Review of prenatal records and labs
 Physical exam
 1. Vitals and routine physical exam
 2. Abdominal Exam


Palpation of contractions
Leopold’s maneuvers
 3. Pelvic Exam
 4. Fetal heart rate monitoring
Review of Prenatal Records
 Allergies
 Medications
 Past medical, surgical, obstetrical, gynecologic, social
and family histories
 Routine prenatal lab work
 Complications of current or past pregnancies
Abdominal Exam
 1. Palpation of contractions for duration and intensity
 2. Leopold’s maneuvers

To assess estimated fetal weight, fetal lie, presentation and
position, attitude, and (a)synclitism
NORMAL LABOR & DELIVERY
Estimated Fetal Weight
 Leopold’s maneuvers (palpation of the
maternal abdomen)
 Ultrasound estimate of fetal weight
(error of 10 – 15%)
 Maternal estimate of fetal weight
(best)
Fetal Lie
 Lie: relationship between the long axis
of the fetus and the mother
Longitudinal
 Transverse
 Oblique

Fetal presentation
 Presentation: fetal part closet to pelvic inlet
 cephalic
 breech
 shoulder
Fetal position
 Position: relationship of fetal presenting part to
the maternal pelvis
 Occiput
 Brow
 Mentum
 Breech
 Shoulder
Fetal Attitude
 The relationship of the fetal parts to one another (i.e.
flexion  extension of head relative to body).
Vertex
Parietal
Brow
Face
(A)synclitism
 Synclitism is when the biparietal diameter of the fetal
head is parallel to the planes of the maternal pelvis.
Pelvic Exam
 Pelvic Exam – sterile vaginal exam +/- sterile speculum
exam
 Dilation
 Effacement
 Station
 Also position of cervix and consistency important.
Obstetrical Pelvic Exam
 Dilation (dilatation): patency of the internal cervical
os
 0 = “closed”
 10 cm = “complete”
 Effacement: shortening of the cervical length
 0% = “thick”
 100% = “fully effaced”
Obstetrical Pelvic Exam
Station: level of presenting part
(bony portion) in relation to the
maternal ischial spines
 Ischial spines = O station
 Above spines: -5 to -1
 Below spines: +1 to +5
Obstetrical Pelvic Exam
 Also includes same assessment included in
Leopold’s maneuvers (fetal lie, presentation,
position, etc.)
Fetal Monitoring
 Intermittent
 Continuous
Continuous Fetal Monitoring
 Baseline rate
 Variability
 Presence of accelerations
 Presence of decelerations
 Changes or trends of FHR patterns over
time
 Contractions
Fetal Heart Rate Baseline
10 minute window
Duration: at least 2 minutes
Bradycardia: < 110 bpm
Tachycardia: > 170 bpm
Fetal Monitoring (Variability)
 Concept of short and long-term
variability dropped
 Absent: undetectable
 Minimal: undetectable - < 5 bpm
 Moderate: 6 - 25 bpm
 Marked: > 25 bpm
Fetal Monitoring
(Accelerations)
 Onset to peak: < 30 seconds
 > 32 weeks: >15 bpm X >15 secs
 < 32 weeks: > 10 bpm X > 10 secs
 > 2 minutes in duration: prolonged
 > 10 minutes in duration: change in
baseline
DECELERATIONS
Fetal Monitoring (Variables)
Onset to nadir < 30 secs
> 15 bpm below baseline
 Duration: > 15 seconds
< 2 minutes from onset to return
to baseline
DECELERATIONS
Fetal Monitoring (Variables)
Treatment
 Pelvic exam (rule out prolapsed cord)
 Maternal oxygen
 Change maternal position
 Stop pushing
 Amnioinfusion
Fetal Monitoring
(Early Decelerations)
Onset to nadir > 30 secs
Coincident in timing with UC
Nadir occurring simultaneously
with the peak of the contraction
Fetal Monitoring
(Late Decelerations)
Onset to nadir > 30 secs
Delayed in timing
Nadir occurring after the peak of
the contraction
Reccuring can be ominous
Fetal Monitoring
(Late Decelerations)
Treatment
 Correct hypotension or other maternal
conditions
 Maternal oxygen
 Scalp stimulation
 Cesarean delivery if repetitive
Uterine Contractions
External tocodynamometry
Internal tocodynamometry
What’s going on in there?
 The cardinal movements of labor are the mechanism
by which the fetus moves progressively through the
birth canal.
Cardinal Movements of Labor –
Occurring during first and
second stages of labor
Engagement: descent of biparietal diameter to the level
of the ischial spines (0 station)
1.

2.
3.
Often occurs before onset of labor in nulliparous patients
Descent
Flexion: presenting diameters of fetal head presenting to
maternal pelvis are optimized
Cardinal Movements of Labor
4. Internal rotation: fetal occiput rotates
from transverse to AP
5. Extension: head rotates under
symphysis pubis
6. External rotation (restitution): occiput
and spine assume same position
7. Expulsion: fetal body delivers
rd
3
and
th
4
stages
 Delivery of placenta
 Bonding, etc
So what if it doesn’t happen
like that?
 Disorders of the 4 stages of labor
Abnormalities of Labor
THE 5 “P”
 Passageway: maternal pelvis
 Powers: uterine contractions
 Passenger: fetus
 Placenta: perfusion
 Psyche: mother’s readiness
st
1
stage disorders
Slow rate of dilation in the active
phase of labor
 < 1.2 cm/hr in nulliparas
 < 1.5 cm/hr in multiparas
 Abnormal latent phase
 Abnormal Active phase
Abnormal Latent Phase of
Labor
 > 20 hours in nulliparas
 > 14 hours in multiparas
 Treatment
 Therapeutic rest
 Morphine (10- 20 mg)
 Hypnotic (Ambien)
 85% proceed into active phase of labor
 10% - no contractions
 5% - may need oxytocin
Disorders of the Active Phase
 Secondary Arrest: cessation of previously
normal rate of dilation for two hours
 Combined Disorder: cessation of
dilation when patient has previously
exhibited a primary dysfunctional labor
nd
2
stage disorders
Disorders of the Second Stage
 Protracted Descent:
 < 1 cm/hr in nulliparas
 < 2 cm/hr in multiparas
 Prolonged:
 Nulliparas


With epidural – 3 hours
No epidural – 2 hours
 Multiparas


With epidural – 2 hours
No epidural – 1 hour
Episiotomy
Need for this now signifies an
abnormality of second stage
 Originally thought to protect perineum
 Now thought to result in more 3rd and
4th degree extensions
 More perineal pain
 At UNC less that 3% of patients
Forceps Assisted Vaginal
Delivery
 Outlet forceps:
 Scalp visible at the introitus w/o parting the labia
 Sagittal suture < 45 degrees
 Low forceps:
 Leading point of skull at +2 or below


< 45 degrees
> 45 degrees
 Mid-forceps:
 Head is engaged but presenting part is above +2 station
 Rarely done
NORMAL LABOR & DELIVERY
Vacuum vs Forceps
 Forceps
 More maternal trauma
 Minimal fetal trauma (bruising)
 Vacuum
 Less maternal trauma
 Potential for increased fetal trauma
(subgaleal bleeding)
Mitivac vacuum
Ritgen Maneuver
Erb’s palsey
rd
3
stage disorders
Retained placenta
 Adherent
 Accreta, etc
POST PARTUM HEMORRHAGE
Causes:
 Atony of the uterus
 Placenta problem
 Laceration
Defined as greater than 500 ml for vaginal birth
Average EBL with C/S = 1000ml.
TREATMENT FOR PPH
 Find the cause and treat promptly
 Active management of the third stage
 Med: Pitocin
Cytotec
Methergine
Hemabate
And now you want to do what?
 Laceration repair
NORMAL LABOR & DELIVERY
Lacerations
 Cervical (use clock to describe location)
 Vaginal (left or right)
 Periurethral
 Clitoral
 Perineal
 1st degree: skin only involved
 2nd degree: skin and subcutaneous tissue
 3rd degree: external rectal sphincter
 4th degree: rectal mucosa not intact
First degree
External sphincter
Second degree
External sphincter
Third degree
Disorders of
th
4
stage
 Bonding
 Delayed postpartum hemorrhage
Induction of Labor – Why mess
with a good thing?
 Maternal or fetal medical indications
 EGA
 PROM/PPROM
INDUCTION OF LABOR
Bishop Score
0
1
2
3
Dilation
Closed
1-2
3–4
>5
Effacement
0 – 30
40 – 50
60 – 70
> 80
Station
-3
-2
-1
+1, +2
Consistency
Firm
Medium
Soft
Position
Posterior
Mid
Anterior
INDUCTION OF LABOR
Oxytocin
 Peptide from posterior pituitary
 Usually given IV; can be given IM
 IV bolus = hypotension
 10 units/ml; dilute in 1000 cc LR
 Routine dose: Start at 2mu/min,
 2 mu/min every 15-30 minutes to 36 IU/min
 Active management of labor: start at 6 mu/min,  by
6 mu/min every 15 minutes to 36 mu/min
 High doses – ADH effect = water intoxication
INDUCTION OF LABOR
Misoprostol (Cytotec®)
 PO tablet FDA approved to prevent gastric ulceration in
patients taking NSAID’s
 PGE1
 25 mcg (1/4 of 100mcg tablet) in vagina Q 4 hours X 4
doses
 Wait 6 hours after last dose to start oxytocin
 Contraindicated with uterine eschar
NORMAL LABOR & DELIVERY
Foley Bulb
 Place special foley through cervix and inflate balloon to
30 cc
 Tape to thigh – remove by 12 hours
 Used when Cytotec contraindicated – previous uterine
incision
 Mechanism: mechanical/local release of prostaglandins
 Frequently used with pitocin
Other things to consider
 Maternal pain relief
 GBS status
 Twins/Multiple
 Breech
 Caesarean delivery
 VBAC
NORMAL LABOR & DELIVERY
Anesthesia/Analgesia
 Cesarean section
 Spinal
 Epidural
 General (more risky in obstetrics)
 Vaginal delivery
 IV pain meds
 Local
 Pudendal
 Epidural
 Combined spinal/epidural
Pudendal Block
GBS Protocol
 Routine culture at 35-37 weeks
 Culture lower 1/4 vaginal and peri-
anal area
 Culture stable up to 96 hours in
Amies transport media
 If patient allergic to penicillin, get
susceptibility testing
GBS Epidemiology
 10-30% of pregnant women colonized
 Vertical transmission may occur
 Neonatal invasive GBS infection decreased
21% from 1993 to 1998.
 In 2000 rate was .23 per 1000 live births
 Early onset infection
 Antibiotics in labor will reduce
 Prevents 225 newborn deaths per year
 Late onset infection
Multiple Gestation
 Twins
Vertex/vertex – vaginal delivery
 Vertex/breech or transverse lie – breech
of 2nd twin
 Breech/other – C-section (locked twins)

extraction
 Triplets or higher order gestation
 Cesarean delivery indicated
NORMAL LABOR & DELIVERY
Breech Presentation
 37 weeks gestation – external cephalic
version (50% success)
 Ultrasound
 Non-stress test
 IV/subcutaneous terbutaline for tocolysis
 Ultrasound monitoring
 Repeat non-stress test
 Cesarean section vs. vaginal birth
BREECH
Frank breech
Complete breech
Incomplete breech
NORMAL LABOR & DELIVERY
Cesarean Delivery
Other
14%
Breech
12%
Fetal
Distress
9%
Repeat C/S
35%
Dystocia
30%
VBAC/Trial of Labor
 One previous LTCS (1% rate of rupture)
 Two previous LTCS (2% rupture)
 Unknown incision (up to 7% rupture)
 Success of TOLAC = VBAC (vaginal birth
after cesarean section): 60 – 80%
USA TRENDS