Lecture 8 - L & D Flashcards
What defines labor?
painful contractions that dilate the cervix progressively
How is labor triggered?
theory – fetus releases cortisol causing placental formation of androgens, decrease in placental progesterone, and increase in estrogen and PGs
What control uterine growth during pregnancy?
estrogen, progesterone, and distention
this is mainly hypertrophy and less cell division
What coordinates contractions?
gap junctions that are formed by estrogen and prostaglandins
contractions spread as current flows from cell to cell
How are contractions inhibited during quiescence?
progesterone
absence of gap junctions
What happens to the uterus during activation?
uterine stretch
activation of HPA axis
formation of oxytocin receptors
How does labor being (chemically)?
placental production of CRH –positive feedback loop for cortisol
What is happening hormonally during the stimulation of labor?
CRH release –> cortisol
fall in progesterone
rise in estrogen
PG –> cervical softening
gap junctions –> coordinate muscle contractions
fetal membrane activation –> rupture of membranes
oxytocin – contractions
What is the cervix made of?
collagen and a small amount of smooth muscle
in response to PG it changes to soft and pliable
What happens to the cervix in response to PG?
collegenolysis (becoming more smooth)
increase in hyaluronic acid
decrease in dermatan sulfate
increase in water content
What is the baby supposed to do in response to reaching the pelvic floor?
flex the neck
making the smallest diameter –suboccipitobregmatic
What are the 3 things we are checking when examining mom’s cervix?
station (of the baby in regards to the ischial spine landmarks)
dilation
effacement
Stage 1 of Labor
Dilation and thinning of cervix
latent phase:
- early labor
- softening and thinning of the cervix
- minimal dilation
active phase:
- more rapid cervical dilation
- usually starts around 4-6cm
may last up to 24 hours
Effacement
typically precedes dilation
thinning out of the cervix
Stage 2 of labor
full dilation to delivery of baby
variable in length
Stage 3 of labor
delivery of baby to delivery of placenta
usually lasts <30 minutes
the placenta should be delivered 2-5 minutes post baby but up to 30 minutes –any longer you should interveine
Stage 4 of labor
puerperium (postpartum period)
What are the 3 Ps of abnormal labor?
Power: force of contractions
-administer oxytocin if inconsistent or weak contractions
Passenger: fetal size, presentation
-progress through the cardinal movements
Pelvis: bony pelvis
-cephalopelvic disproportion
What are indications of operative delivery?
vacuum and forceps
prolonged 2nd stage of labor
suspicion of immediate/impending fetal compromise
aid after coming head in breech vaginal delivery
shorten 2nd stage of labor for maternal benefit (only if strong valsalva efforts harm the mom- this is the only exception to pull the baby when mom isn’t pushing)
What are the indications of C-section?
labor dystocia h/o cesarean section malpresentation fetal distress placent previa
What are the different types of insertions for C-section?
Classical (prevents them from ever being able to do vaginal delivery)
Low transverse (ideal)
How can you aid in cervical ripening?
prostaglandin E2 or E1
mechanical:
- insert foley in cervix and apply pressure from inside
Bleeding postpartum is normal for how long?
5-8 weeks
What are anatomic and physiologic changes can you expect postpartum?
Uterus -decrease in size -cervical elasticity changes -discharge progression: lochia rubra --> serosa --> alba Vagina gradually regain tone
Return to menstruation
usually 6-8 weeks –> longer if you are breastfeeding (up to 6 months)
CV –urination increases to expel excess plasma volume
Postpartum blues is normal for 2-3 weeks
What are the maternal benefits of breastfeeding?
decrease postpartum depression
boosts weight loss
uterine involution (suckling –> oxytocin release –> uterine contractions –> minimizes hemorrhage)
Colostrum
early breast milk production
can start during pregnancy to 2nd day postpartum
evolves to mature milk in the first few weeks
What can suppress lactation?
Pharm intervention not recommended (bromocripitne, estrogen)
supportive bra
NSAIDs
Mastitis
often within 2-4 week postpartum
Staph Aureus MC
tx. dicloxacillin
if PCN allergy - cephalosporin or vacno
What is pseudoephedrines effect on lactation?
suppress lactation (even just a single dose)
What is domperiones effect on lactation?
boosts lactation
selective dopamine antagonist
Can a pregnant pt take NSAIDs?
no
there is a risk of premature closure of the infant PDA
Can a breastfeeding mom take NSAIDs?
yes
What medications can a breastfeeding mother not take d/t risk of passing it to baby?
narcotics
nitrofurantoin —infants without G6PD may develop hemolytic anemia
What is the MC cause of maternal death?
hemorrhage
What are the common causes of abnormal 3rd trimester bleeding?
placenta previa
abruption
preterm labor
Placenta previa
placenta covers the opening of the cervix
will need C section
Placeneta accreta
uncommon
typically results from trauma or prior surgery –defective decidual layer
the placenta attaches too deeply to the uterus
tx: total hysterectomy at the time of c-section
if you dont know ahead of labor and they go into vaginal delivery –they won’t deliver the the placenta
What is the MC cause of placenta accreta?
prior C section
Abruptio placentae
premature separation of placenta
initiated by hemorrhage to decidua basalis –> decidual hematoma –> separation of decidua from basal plate –> further separation and bleeding –> DIC
Risk factors: HTN hx abruption trauma short umbilical cord folate deficiency
DIC
risk of abruptio placenta
basically she bleeds out all of her clotting factors
we treat by giving clotting factors
What can cause uterine rupture?
prior c section scar opens during next labor
Fetal bleeding
rupture of fetal umbilical vessel
hard to tell that its not just the mother bleeding
can do Apt test but that might take too long
basically if you have any suspicion that it is fetal blood go straight to surgery
What are causes of postpartum hemorrhage?
uterine atony
trauma, uterine inversion
retained placental tissue
coagulation disorder
Uterine atony
reason of postpartum hemorrhage
failure of uterine contraction post delivery
tx: oxytocin, methylgonovine, PG (potocin)
to help contract the uterus and prevent bleeding
given to EVERY WOMEN post delivery of baby
What are the most common causes of maternal death?
hemorrhage
embolism
HTN crisis
infection
How do you dx postpartum maternal infection?
> /= 39C
> /=38 + clinical finding (tachycardia, leukocytosis)
more common with C-sections
risk factors: prolonged labor and/or membrane rupture
GBS infection
some women have this naturally in their flora but it is bad for children so we treat them for the “infection” during their 38th week of pregnancy
treating any earlier wont do anything since the bugs are likely to come back
if the infant gets this it can cause sepsis, PNA, bacteremia, meningitis
Postpartum hemorrhage
> 1000 mL blood loss with delivery plus sxs of hypovolemia
Intrapartum and up to 24h postpartum
MC cause:
Uterine atony
