labor and delivery lecture

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


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!!)


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


4/23

Your Favorite: Hormones!

Fetal HormonesHigh Estrogen vs.P rogesterone

ProstaglandinsO xytocinRelaxin

A ll combine for aP O SITIVE feedbackloop


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


6/23

E strogen andP rogesterone

Progesteroneinhibitscontractibility

Estrogen increasescontractibility

A t 7th month,estrogen stillincreasing but

progesterone dropsoff slightlyHigh Estrogen:P rogesterone ratioexcites uterus


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!!


8/23


9/23


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


11/23


12/23

Three Stages of LaborDilation andEffacement

Descent andExpulsionExpulsion of P lacenta


13/23

StageO

ne: DilationIntermittent contractions < 10

minutesCervix dilating andthinning

A verage 1 2 hours

primigravidas, 7hours formultigravidas


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


15/23

BreechP

resentation


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


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


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


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


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


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


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)


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

labor and delivery lecture

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