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8/3/2019 Labor and Delivery Lecture
1/23
Labor and DeliveryMarcela s Recipe forHaving a Baby:
2 cup Mechanics2
cups Hormones3 cup emotional &physical support
Mix and Stir withthe three stages of laborTime: 8 - 48 hoursMakes three: one
new mom, one newdad and a brandnew baby
8/3/2019 Labor and Delivery Lecture
2/23
P arturitionBirth of the babyBoth Biological and Social Event Expected Day of Delivery
266 days (38 weeks) after fertilization 2 80 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!!)
8/3/2019 Labor and Delivery Lecture
3/23
I t s Like a Marathon:The Body P repares
Training: fitness of momand fetus are important during labor (rememberhypoxia bad!)Stretching: Ligaments relaxesp. pubic symphisis makingmore room in pelvic brim
Practice makes perfect:
Braxton-Hicks Contractionsgive the top myometrium aworkout, stretch the bottommuscles and help dilate thecervix
8/3/2019 Labor and Delivery Lecture
4/23
Your Favorite: Hormones!
Fetal HormonesHigh Estrogen vs.P rogesterone
ProstaglandinsO xytocinRelaxin
A ll combine for aP O SITIVE feedbackloop
8/3/2019 Labor and Delivery Lecture
5/23
O n Y our Mark, Get Set, Go!The O nset of Labor
Fetal Hypothalmus secretes Corticotropin ReleasingHormone near term which stimulates theFetal A nterior P ituitary to secrete adrenocorticotropinhormone ( A CTH)
A CTH stimulates fetal adrenal cortex to producecortisolCortisol stimulates secretion of estrogen from
placenta, inhibition of P synthesis -> uterinecontractions -> stimulates oxytocin -> hypFetuses with adrenal hypoplasia are often post-dateand labor is slow to start
8/3/2019 Labor and Delivery Lecture
6/23
E strogen andP rogesterone
Progesteroneinhibitscontractibility
Estrogen increasescontractibility
A t 7th month,estrogen stillincreasing but
progesterone dropsoff slightlyHigh Estrogen:P rogesterone ratioexcites uterus
8/3/2019 Labor and Delivery Lecture
7/23
Ox ytocin: The Hormoneof Love -Michel O dent
Peptide hormone created in hypothalmusO nce E: P stimulating contraction,
hypothalmus signaled to send oxytocin toposterior pituitaryE and P rostaglandin increase sensitivity of oxytocin receptors
Stimulates uterine contraction and breasts A dministered to stimulate labor as pitocin
Fun Fact: hormone involved in orgasm!!
8/3/2019 Labor and Delivery Lecture
8/23
8/3/2019 Labor and Delivery Lecture
9/23
8/3/2019 Labor and Delivery Lecture
10/23
Two More!!P rostagladins
Release stimulated
by estrogen andoxytocin A lso stimulates
oxytocin (+ loop)
Promotes uterinecontractions
Relaxin Peptide hormone
produced by thecorpus luteumLooses ligaments
Softens cervixIncreases # of oxytocin receptors
8/3/2019 Labor and Delivery Lecture
11/23
8/3/2019 Labor and Delivery Lecture
12/23
Three Stages of LaborDilation andEffacement
Descent andExpulsionExpulsion of P lacenta
8/3/2019 Labor and Delivery Lecture
13/23
StageO
ne: DilationIntermittent contractions < 10
minutesCervix dilating andthinning
A verage 1 2 hours
primigravidas, 7hours formultigravidas
8/3/2019 Labor and Delivery Lecture
14/23
V erte x and TransverseP ositions
Vertex position (headdown) is normal
Uterus contractspushing the occiput bone to put pressure oncervix to dilateTransverse lie is worst case scenario withshoulder as presentingpart
8/3/2019 Labor and Delivery Lecture
15/23
BreechP
resentation
8/3/2019 Labor and Delivery Lecture
16/23
Stage Two:Ex
pulsionBegins when cervixfully dilated (10 cm)
Contractions arestrongest at top of uterus pushing fetusdownward
A verage 50 minutesprima, 2 0 min multi Head Crowing
8/3/2019 Labor and Delivery Lecture
17/23
Can You Tell theDifference?
Most US hospitals encourage women to deliver in
supine position Physiologically worst position because works against gravity, compresses blood vessels endangering babyand increases chance of 3rd and 4th degree tearswith episiotomy
8/3/2019 Labor and Delivery Lecture
18/23
W orking HardMom and Baby
Pain from contractions comes first fromhypoxia to uterine muscles and then from
stretching and strainingContractions intermittent because baby sblood supply compromised and fetal HR dropswith every contraction, thus hypoxia canoccur (esp when too much pit is given)Baby is an active participant in birth pushingand negotiating bony structure to get throughbirth canal
This Little Guy is All Tuckered O ut
8/3/2019 Labor and Delivery Lecture
19/23
Stage 3:P
lacenta Uterus contracts reducing
area of attachment Separation of placentaresults in bleed and clotting
Placenta expelledRepresents stage whenhemorrhage can occur
Pitocin administered to aiduterine contractionManual Extraction if retainedLasts about 15 minutes
8/3/2019 Labor and Delivery Lecture
20/23
R ecovery TimeContraction of uterus result inconstriction of spiral arteries(what was their role again?)Mother - Father - BabyBonding Time: intense periodof hormone release: prolactin,serotonin, dopamine, thehappy hormonesIn first hour of life, babies cancrawl and self-attach to breasthowever babies that aredrugged are almost always toodisoriented to do so
Happy Mom Breastfeeding
8/3/2019 Labor and Delivery Lecture
21/23
I f All E lse FailsCesarean Section
Indications: Cord P rolapse Tranverse Lie Fetal Distress P lacenta P revia P lacenta A bruption Failure to P rogress VB A C: risk of uterine
rupture Cephlo- Pelvic
Disproportion
8/3/2019 Labor and Delivery Lecture
22/23
W arning: MidwifeSpeaking
US C-section rate 2 5-30% WHO says >10% unnecessary
Interventions such as epidurals,
withholding food and water,supine position increase chanceof C-sectionHospital settings induceanxiety, release of adrenaline,labor ST O PSFeminist critique: Much of language used to describe birthis very unempowering (iefailure to progess, stubbornuterus)
8/3/2019 Labor and Delivery Lecture
23/23
If we hope to createa non-violent world where respect and kindness
replace fear and hatred
We must beginwith how we treat each other at the beginning of life.
For that is whereour 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