Labor and Delivery
Marcela’s Recipe for
Having a Baby:
• 2 cup Mechanics
• 2 cups Hormones
• 3 cup emotional &
physical support
• Mix and Stir with
the three stages of
•Time: 8 - 48 hours
•Makes three: one
new mom, one new
dad and a brand
new baby
Birth of the baby
Both Biological and Social Event
Expected Day of Delivery
266 days (38 weeks) after fertilization
280 days (40 weeks) after last menstrual period
Onset of Labor not completely understood but
we do know it’s about:
1. Mechanical Factors (psst this means muscles)
2. Hormonal Factors (oh yes there are more!!)
It’s Like a Marathon:
The Body Prepares
• Training: fitness of mom
and fetus are important
during labor (remember
hypoxia bad!)
• Stretching: Ligaments relax
esp. pubic symphisis making
more room in pelvic brim
• Practice makes perfect:
Braxton-Hicks Contractions
give the top myometrium a
workout, stretch the bottom
muscles and help dilate the
Your Favorite: Hormones!
• Fetal Hormones
• High Estrogen vs.
• Prostaglandins
• Oxytocin
• Relaxin
• All combine for a
POSITIVE feedback
On Your Mark, Get Set, Go!
The Onset of Labor
• Fetal Hypothalmus secretes Corticotropin Releasing
Hormone near term which stimulates the
• Fetal Anterior Pituitary to secrete adrenocorticotropin
hormone (ACTH)
• ACTH stimulates fetal adrenal cortex to produce
• Cortisol stimulates secretion of estrogen from
placenta, inhibition of P synthesis -> uterine
contractions -> stimulates oxytocin -> hyp
• Fetuses with adrenal hypoplasia are often post-date
and labor is slow to start
Estrogen and
• Progesterone
• Estrogen increases
• At 7th month,
estrogen still
increasing but
progesterone drops
off slightly
• High Estrogen:
Progesterone ratio
excites uterus
Oxytocin: “The Hormone
of Love” Michel Odent
• Peptide hormone created in hypothalmus
• Once E:P stimulating contraction,
hypothalmus signaled to send oxytocin to
posterior pituitary
• E and Prostaglandin increase sensitivity of
oxytocin receptors
• Stimulates uterine contraction and breasts
• Administered to stimulate labor as pitocin
• Fun Fact: hormone involved in orgasm!!
Two More!!
• Release stimulated
by estrogen and
• Also stimulates
oxytocin (+ loop)
• Promotes uterine
Peptide hormone
produced by the
corpus luteum
Looses ligaments
Softens cervix
Increases # of
oxytocin receptors
Three Stages of Labor
• Dilation and
• Descent and
• Expulsion of
Stage One: Dilation
• Intermittent
contractions < 10
• Cervix dilating and
• Average 12 hours
primigravidas, 7
hours for
Vertex and Transverse
• Vertex position (head
down) is “normal”
• Uterus contracts
pushing the occiput
bone to put pressure on
cervix to dilate
• Transverse lie is worst
case scenario with
shoulder as presenting
Breech Presentation
Stage Two: Expulsion
• Begins when cervix
fully dilated (10 cm)
• Contractions are
strongest at top of
uterus pushing fetus
• Average 50 minutes
prima, 20 min multi
Head Crowing
Can You Tell the
• Most US hospitals encourage women to deliver in
supine position
• Physiologically worst position because works against
gravity, compresses blood vessels endangering baby
and increases chance of 3rd and 4th degree tears
with episiotomy
Working Hard
Mom and Baby
• Pain from contractions comes first from
hypoxia to uterine muscles and then from
stretching and straining
• Contractions intermittent because baby’s
blood supply compromised and fetal HR drops
with every contraction, thus hypoxia can
occur (esp when too much pit is given)
• Baby is an active participant in birth pushing
and negotiating bony structure to get through
birth canal
This Little Guy is All Tuckered Out
Stage 3: Placenta
• Uterus contracts reducing
area of attachment
• Separation of placenta
results in bleed and clotting
• Placenta expelled
• Represents stage when
hemorrhage can occur
• Pitocin administered to aid
uterine contraction
• Manual Extraction if retained
• Lasts about 15 minutes
Recovery Time
• Contraction of uterus result in
constriction of spiral arteries
(what was their role again?)
• Mother - Father - Baby
Bonding Time: intense period
of hormone release: prolactin,
serotonin, dopamine, the
happy hormones
• In first hour of life, babies can
crawl and self-attach to breast
however babies that are
drugged are almost always too
disoriented to do so
Happy Mom Breastfeeding
If All Else Fails
Cesarean Section
• Indications:
Cord Prolapse
Tranverse Lie
Fetal Distress
Placenta Previa
Placenta Abruption
“Failure to Progress”
VBAC: risk of uterine
– Cephlo-Pelvic
Warning: Midwife
• US C-section rate 25-30%
• WHO says >10% unnecessary
• Interventions such as epidurals,
withholding food and water,
supine position increase chance
of C-section
• Hospital settings induce
anxiety, release of adrenaline,
labor STOPS
• Feminist critique: Much of
language used to describe birth
is very unempowering (ie
failure to progess, stubborn
If we hope to create
a non-violent world
where respect and kindness
replace fear and hatred
We must begin
with how we treat each other
at the beginning of life.
For that is where
our deepest patterns are set.
From these roots
grow fear and alienation
~or love and trust.
~Suzanne Arms
If we want to create a less violent world, we
must begin with birth

Labor and Delivery - Viscodes and sks99