The Birth Process
Mamie Guidera, CNM, MSN
Carol O’Donoghue, CNM, MSN, MPH
Normal Labor and birth:
Objectives
Introductions
Physiologic labor and birth: the basics
Phases of labor
Birth video
The P’s: Power, passageway, passenger, etc.
Briefs:
American birth & (some of the) influences:
Where births take place
Cultural expectations of pain management
A word on Fetal Monitoring
What is “normal” labor?
An introduction
Length of first stage labor in healthy nulliparous
and multiparous childbearing women
adapted from Albers L. (2007)
bold = nullips, italics = multips
Mean (hrs)
95th percentile (hrs)
Friedman (1978)
4.1
8.5
Kilpatrick & Laros
(1989)
8.1
16.6
Albers, Schiff &
Gorwoda (1996)
7.7
19.4
Albers (1999)
7.7
17.5
Friedman (1978)
2.4
7.0
Kilpatrick & Laros
(1989)
5.7
12.5
Albers (1996)
5.7
13.7
Albers (1999)
5.6
13.8
Cervical Examination:
examining the passageway
Dilatation
Effacement
Station
Position
Consistency
Presenting part
Status of membranes
The Passage
Pelvic Bones and Pelvimetry
Passenger: Attitude
Passenger: Presentation
Passenger
Descent
Fetal head journey through the pelvis
until Crowning
Flexion
Fetal head tucks into chest
Important so that smallest diameter of head presents
May depend on pelvic type/shape
Passenger: Station
Engagement
AKA “dropping” or “lightening”
At the level of ischial spines = 0 station
Above ischial spines
-5 to -1
-5 = unengaged
Below ischial spines
+1 to +5
+5 = crowning
Passenger: Presentation
Second Stage of Labor
From 10 cm to birth
of baby
Pushing or expulsion
Contraction pattern
Duration
Birth
Perineal management
(keep your hands off
Mirror
Ask mother to feel
the baby’s head
Stay focused on
woman, not tasks
Third Stage of Labor
Birth of the placenta
5 to 30 minutes….or more
Signs of placental separation
Inspection
A word on Active Management of Third
Stage
Pitocin and prevention of postpartum
hemorrhage
Two Methods of Third Stage
Management
 Physiologic (“expectant”) management
Oxytocics are not used
Placenta is delivered by gravity and maternal effort
Cord is clamped after delivery of the placenta
 Active Management
Oxytocic is given
 [Cord is clamped]
Placenta delivered by controlled cord traction (CCT) with
counter-traction on the fundus
Fundal massage after delivery of placenta
Part II:
Reality & modern hospital birth: pain management,
monitoring, interference with physiologic birth
Physiology of labor pain: First stage
o Uterine contractions:
o Myometrial ischemia
Causes release of potassium, bradykinin, histamin, serotonin
o Distention of lower uterine segments and cervix
o Stimulates mechanorecoptors
Impulses follow sensory-nerve fibers from paracervical and
hypogastric plexus to lumbar sympathetic chain
Enter dorsal horn of spinal cord at T10-12, L1
Pain pathways during labor: Late
first and Second stage
o Transition associated with greater nocioceptive
input related to increased somatic pain from
vaginal distention
o Distention of vagina, perineum, pelvic floor,
stretching of pelvic ligaments
o Pain signal transmitted to spinal cord via S2-S4
(includes pudendal nerve)
Pain Management in Active
Labor
Walking/Movement
Hydrotherapy
Back Rubs
Birth Ball, toilet
Maternal Preference
Analgesia/ Anesthesia
Others?
hydrotherapy
Continuous Labor Support
o Non-medical care by a trained
person
o Different definitions/criteria
depending on studies:
o “minimum of 80%” presence
o presence “without interruption, except
for toileting”
o Various terms: doula, labor
assistant, birth companion,
monitrice
o May refer to husband or untrained
female companion
Kennell J, Klaus M, McGrath S, Robertson S,
Hinkley C. Continuous Emotional Support During
Labor in a US Hospital: A Randomized Controlled
Trial. JAMA, May 1991; 265: 2197 - 2201.
•616 women
•Three arms: supported (doula), observed,
control groups
•Outcomes studied: epidural use, duration of
labor, oxytocin use, prolonged infant
hospitalization and maternal fever all
significantly less with supported group
•More spontaneous birth with supported
group
Hodnett, ED et al (2007). Continuous support for
women during childbirth (Review). Cochrane Database
of Systematic Reviews 2007, Issue 3. Art No.: CD 003766.
16 trials, all RCTS
o 13,391 women
o Women with CLS were:
o
o
o
o
Less likely to have regional anesthesia
Less likely to have any analgesia/anesthesia
Less likely to have an operative delivery
Less likely to report dissatisfaction and low leves
of control with the CB experience
o Less likely to use EFM
o …and were more likely to have a shorter
labor length and a spontaneous vaginal
birth.
Continuous Labor Support: Mechanism of Action from Hodnett (2007)
Positive impact
of
companionship
on mom
Mitigates
potentially
harsh
environment
Negative
experiences
may impede
labor
Negative
experiences may
impede adjustment
to motherhood
Physiologic
impact of
continuous
labor support
Mobility
encouraged by
support
person
Support
person
decreases
anxiety of mom
fetopelvic
relationship
is enhanced
stress hormones
(epinephrine)
may be
reduced
woman
uses
gravity &
position changes
fewer
abnormal
FHR
patterns
preserves
uterine
contractility
Epidurals: how do they contribute to
prolonged labor or dx of labor dystocia, if at
all?
Length of labor
First stage labor not impacted
Studies do not uniformly look at or control for
confounding factors such as rate of dilation or rates of
spontaneous labor
Length of second stage longer
General agreement
Malpresentation
3 RCTs, 2 observational studies: significant
findings, significant crossover in RCTs
Lieberman & O’Donoghue, Am J Obstet Gynecol 2002, 186(5):S31-S68.
Leighton& Halpern Am J Obstet Gynecol 2002, 186(5):S69-77.
Monitoring for fetal well-being: the
evidence
Monitoring FHR: a short history
 1600s:
Marsac of France describes the sound of FHTs
Marsac’s colleague Phillipe LeGaust mentions FHTS in a poem
Kilian proposes that FHTs be used to dx fetal distress and when a clinician
should intervene
 1800s:
1818: auscultation via maternal abdomen helps dx fetal viability and fetal
lie
1893: VonWinckel defines criteria for fetal distress that remained
unchanged until the 1960s
Gabbe (2002), 4th Ed.
Monitoring FHR: a short history
 1958
 American Edward Hon (“father of EFM”) reports on instantaneous FHR recording
 Hon collaborated with Calderyo-Barcia (Uruguay) and Hammacher (Germany) to
describe patterns that would diagnose fetal distress
 1968:
 Benson et al: review of 24,000 cases of auscultation and outcomes; determined that
“there was no reliable indicator of fetal distress in terms of FHR save in extreme
degree.”
 Late 1960s: first commercially available electronic FHR monitor available
 By late 1970s EFM used in most American labor and delivery units
 By 1978, 66% of women EFM used during their labors
 In 2002, 85% of labors included EFM
Gabbe (2002), 4th Edition; Williams (2005), 22nd Edition
Original Assumptions of EFM
 Electronic fetal heart rate monitoring provided accurate
information
 The information was of value in diagnosing fetal distress
 It would be possible to intervene to prevent fetal death or
morbidity
 Continuous electronic fetal heart rate monitoring was
superior to intermittent methods
Williams Obstetrics (2005), 22nd Edition
Monitoring FHR: the evidence
 1968:
Benson et al: review of 24,000 cases of auscultation and outcomes;
determined that “there was no reliable indicator of fetal distress in terms of
FHR save in extreme degree.”
 Thacker et al (2005) reported in the Cochrane Database (18,561
pregnancies):
Prevention of neonatal seizures
No prevention of cerebral palsy
Abnormal neurological outcomes not higher in infants managed by
intermittent auscultation vs. continuous EFM (CEFM)
Monitoring FHR: a short history
 Thacker’s report now replaced by Alfirevic (2006; >37,000
women):
Seizures decreased; rare outcome 1/500 births
No increase in cerebral palsy, infant mortality “or other
standard measures of neonatal well-being”
Increase in cesarean section and instrumental deliveries
Limits movement of women during labor
CEFM may also mean that “some resources tend to be focused
on the needs of the CTG rather than the women in labour.”
Gabbe (2002), 4th Ed.; Williams (2005), 22nd Edition
Actual Outcomes of Widespread
EFM Use
 By 1994, Symonds writes that 70% of obstetrical litigation
related to fetal brain damage is related to purported
abnormalities on the EFM tracing
 Significant interobserver and intraobserver variability
Studies published prior to NICHD and after guidelines
(1982-2003)
 Increase rate of Cesarean Section delivery
 Increase use of Vacuum and Forceps
 No reduction in perinatal mortality
Incidence of neonatal seizures significantly decreased
 No reduction in cerebral palsy
ACOG Practice Bulletin 70 (2005); Williams (2005), 22nd Ed.
EFM vs Intermittent Auscultation (IA)
 Research does not support one modality over the other
 Most studies comparing the two were only conducted in low risk
patients; Alfirecvic (2006) did include patients receiving oxytocin
 ACOG Practice Bulletin 70 (2005) states:
“Those with high-risk conditions (eg, suspected fetal growth restriction,
preeclampsia, and type 1 diabetes should be monitored continuously).”
 Current USPSTF Guideline (1996 to present):
Routine intrapartum EFM not recommended
Insufficient evidence regarding its routine use in high risk pregnancies
http://www.ahrq.gov/clinic/uspstf/uspsiefm.htm Accessed 6/30/08
Oxytocin Augmentation
Clark SL, Simpson KR, Knox GE, Garite T.
Oxytocin: new perspectives on an old drug. Am J
Obstet Gynecol 2009;200:35.e1-35.e6
.
 We know of no other area of medicine in which
a potentially dangerous drug is administered to
hasten the completion of a physiologic process
that would, if left to its own devices, usually
complete itself without incurring the risk of drug
administration. Yet the administration of
oxytocin is often undertaken under precisely
these circumstances when labor is electively
induced or Braxton-Hicks contractions are
electively augmented.”
Medicalization of labor:
Parkland, Texas
The challenge is, can you provide
vigilance without intervention….
Don’t just stand there.
Do nothing!”
Questions & Comments?