Module 2 - OB Flashcards
First stage of labour
onset of contractions –> full cervical dilation
early/latent = cervix dilates to 3-4 cm, baby continues to drop in pelvic inlet
active = cervix dilates to 8-9 cm
transitional = cervix dilates to 10 cm
Second stage of labour
full cervical dilation –> delivery of baby
latent/passive = mother does not feel urge to push (primary powers)
active = mother actively feels urge to push (secondary powers)
Third stage of labour
delivery of placenta
Active third stage management
oxytocin IM usually given after delivery of anterior shoulder
gentle cord traction
promotes delivery of placenta + reduces r/o PPh
Fourth stage of labour
first few hours after delivery
initiate skin-to-skin and breastfeeding
afterpains may occur d/t involution
Precipitous labour
Dystocia
Pain management during labour (pharmacology)
nitrous oxide (laughing gas)
sterile water injection
epidural/spinal
opioids
general anesthesia
pudendal block
Pudendal block
local anesthesia inserted through vagina into pudendal nerve
pudendal nerve innervates buttocks, perineum, anus/rectum/vulva
DOES NOT take away pain of contractions
Sterile water injection
inserted intradermally/subcutaneously in lower back
works via gate control theory
Nitrous oxide
controlled by mom
can be used for 2-3 hours max
minimal adverse effects
may blunt pain but not remove it
Opioids
fentanyl/morphine
cause feelings of euphoria/anagelsia
if given too close to delivery can lead to respiratory depression in newborn
Epidural/spinal
local anesthesia inserted into epidural space/subarachnoid space
can be used throughout labour
has many adverse fx: dural headache, urinary retention, hypotension, motor block
can affect baby’s ability to breastfeed
General anesthesia
total sedation + anagelsia + amnesiac fx
mom is totally out –> misses pregnancy
may have adverse fx on baby (BF ability)
First stage labour pain
visceral pain
pain felt during contractions
felt in lower back, abdomen, sides
Second stage labour pain
pain increases as contractions become longer and more frequent
pain begins to be felt near perineum
Episiotomy
surgical incision made into perineum to facilitate delivery
4 T’s of PPH
Tone
Trauma
Tissue
Thrombin
Tone RF
overdistended uterus
polyhydramnios
multiple gestation
macrosomia
uterine muscle exhaustion (precipitous labour, prolonged labour, high parity, oxytocin induction)
intra-amniotic infection (fever, prolonged ROM)
placenta abnormalities (previa, fibroid)
uterine-relaxing medication (halogenated anesthesia, nitroglycerin)
distended bladder
How does oxytocin lead to uterine atony?
causes desensitization to oxytocin –> decreased contractions
Trauma RF
laceration (precipitous delivery, assisted delivery)
C/S
uterine rupture
uterine inversion
Tissue RF
retained products - abnormal placentation (accreta, increta, percreta, extra lobe, incomplete delivery)
previous uterine surgery
high parity
abnormal placenta on ultrasound
retained blood clots
atonic uterus
Thrombin
pre-existing blood disorders (hemophilia A, vWD dx, idiopathic thrombocytopenia)
history of liver dx
DIC
Which layer of the uterus contracts to prevent blood loss?
myometrium contracts after birth
this squeezes maternal blood vessels supplying the spiral arteries of the endometrium
Uterotonic drugs
oxytocin
misoprostol
methylergonovine
carboprost
tranaxemic acid
Oxytocin
exogenous hormone
causes uterine contraction
given IM/IV
Misoprostol
prostaglandin causing uterine contractions + antiulcer effects
CI in allergy
given rectal, SL, PO
Methylergonovine
ergot alkaloid
stimulates uterine/vascular smooth muscle contraction
CI in HTN, pre-eclampsia, cardiac disease
givne IM, IU, PO
Carboprost
prostaglandin
causes uterine contractions by stimulating myometrium
CI: asthma, HTN
given IM, IU
Tranaxemic acid
plasminogen inactivator
prevents fibrinolysis
CI: hx of blood clots, concurrent anticoagulant use
given iV
PPH interventions
fundal massage
O2 therapy (simple face mask)
lower HOB
IV access –> blood products, uterotonic drugs (oxytocin), fluid bolus
I&O/indwelling catheter
monitor labs
5 factors affecting labour
Passenger (fetus/placenta)
Pathway (birth canal)
Psychological
Powers (primary and secondary)
Position (of mother)
Passenger factors
size of fetal head
fetal presentation (cephalic, breech - which part of the body facing opening)
fetal lie (longitudinal, transverse, horizontal, oblique)
fetal attitude (flexion)
fetal position (reference point of presenting part to pelvis)
Types of pelvises
gynecoid (normal)
android (masculine)
anthropoid (resembling apes)
platypelloid (oval)
Primary powers
involuntary contractions
Secondary powers
pushing of the mother
Birth position
Station
relationship of presenting fetal part to imaginary line drawn b/w maternal ischial spines
measures how far into pelvic inlet baby has dropped
Contraction characteristics
frequency
duration
intensity
Effacement
shortening/thinning of cervix
Dilation
enlargement/widening of cervix
Lightening
feeling of baby as it drops into true pelvis
Show
vaginal/cervical mucus increases during fetal descent
may be bloody/rust-colored
Cervical ripening
cervix becomes soft
