Module 2A Flashcards
Dilation
the opening or enlargement of external cervical os
What are the 2 main functions of uterine contractions?
to dilate the cervix and to push fetus through birth canal
What happens hormonally and physically to initiate labor?
Estrogen levels increase / progestrone decreases which leads to increase in number of myometrium gap juncations (faciliatate contractions and stretching)
Number of oxytocin receptors increase. Fetal cortisol levels increase synthesizing prostaglandins, uterine contractions are initiated, cervical softening and myometrial sensitization = dilation.
Lightening
occurs when fetal presenting part begins to descend into true pelvis
False labor
condition occuring in later weeks of preg when irregular uterine contractions are felt but cervix is not affected
True labor
contractions occuring at regular intervals that increase in frequency, duration, and intensity. Brings about progressive cervical dilation and effacement
Factors that affect labor process
“five P’s”
- Passageway (birth canal)
- Passenger (fetus and placenta)
- Powers (contractions)
- Position (maternal)
- Psychological response
What are the 5 additional P’s?
- Philosophy
- Partners (support)
- Patience (natural timing)
- Patient preparation
- Pain managment
What is the false pelvis?
Greater - composed of upper flared parts of two iliac bones with their concavities and wings as base of sacrum
Linea terminalis
Imaginary line from scaral prominence at back to superior aspect of symphysis pubis at front
What is the true pelvis?
3 planes?
Bony passageway through which the fetus must travel. Made up of 3 planes. the inlet, mid-pelvis, the outlet
Pelvic inlet?
Entrance toward birth canal
Wider side ways than from front to back
What happens when fetus travels in the mid pelvis
Chest is compressed causing lung fluid and mucus to be expelled. Which removes the space occupying fluid so that air can enter lungs with newborns first breath
What measurements are assessed on the pelvic outlet for vaginal birth?
-Diagonal conjugate of inlet
-Transverse or ischial tuberosity diameter of outlet
-True or ob conjugate
What does diagnoal conjugate and true or ob conjugate need to measure for vaginal birth?
Diagnoal conjugate - at least 11.5cm
True conjugate - 10 cm
The pelvis is divided into what 4 shapes?
Gynecoid
Anthyopoid
Android
Platypelloid
Gynecoid pelvis
-Considered true female pelvis (40% of women)
-Vag birth most favorable
-Inlet is round, outlet roomy, optimal diameters in all 3 planes
*allows early and complete fetal internal rotation during labor
Anthropoid pelvis
-Common in men and non-white women. (25% of women)
-Pelvic inlet is oval and sacrum is long, producing a deep pelvis (wider front to back)
**more favorable compared to android or platypelloid
Android pelvis
-Considered male shaped and characterized by funnel shape (20% of women)
-Pelvic inlet heart shaped. Posterior segment is reduced in all pelvic planes. Descent of fetal head is slow and failure to rotate is common. Usually leads to C-section
Platypelliod (flate) pelvis
Least common (3%)
Pelvic cavity is shallow but widens at pelvic outlet, making it difficult for fetus to descend through mid pelvis.
Labor is poor, arrest at inlet common
What do the soft tissues of the passage way consist of
Cervix, pelvic floor muscles, vagina
Effacement
cervix effaces (thins) to allow presenting fetal part to descend into vagina
What 5 bones are not fused in fetus head?
2 frontal
2 parietal
Occipital
Fetal head
largest fetal structure (1/3 of body length)
What are sutures?
What are fontanelles?
Sutures - membranous spaces between cranial bones
Fontanelles - intersection of these sutures
Why are sutures important in newborns?
Allow cranial bones to overlap in order for head to adjust in shape when pressure is exerted by uterine contractions or maternal bony pelvis
Molding
Changing (elongated) shape of fetal skull at birth from overlapping of cranial bones
Caput saccedaneum
Caphalohematoma
Caput saccedaneum - fluid collected at scalp (can be described as edema). Disappears within 3-4 dats
Caphalohematoma- blood collected beneath scalp. reaborbed in 6-8 weeks
Sutures help the examiner
Detemine position of fetal head and degree of rotation
What is the soft spot called?
Anterior fontanelle
Diamond shape
Measures 1-4cm
Remains open for 12-18months to allow for growth of brain
Posterior fontanelle
Measures?
Located?
Closes?
1-2cm
back of fetal head
8-12 weeks after birth
What are the fetal skull diameters?
Occipitofrontal
Occipitomental
Suboccipitobregmatic
biparietal
BOLD is 2 most important
Fetal attitude
refers to posturing (flexion or extension) of joints and the relationship of fetal parts to one another
- most common is all joints flexed (back is rounded, chin to chest, thighs flexed on abdomen, legs flexed at knees)
What happens if fetal attitude is abnormal (no flexion or extension)?
nonflexed parts increase diameter increasing difficultly
Extension leads to larger fetal skull diameters which may make birth difficult
Fetal lie
Relationship of the long axis (spine) of fetus to the long axis (spine) of mother.
Three possible lies: Longitudinal (most common), transverse, oblique
What is longitudinal lie
Transverse lie
Oblique lie
Longitudinal - long axis is parallel with mothers
Transverse - long axis of fetus is perpendicular to mother
Oblique - fetal long axis is at an angle and no palpable fetal part is presenting. (usually transitioning between other lies)
*Transverse or oblique cannot be delivered vaginally
Fetal presentation
3 main?
refers to the body part of the fetus that enters the pelvic inlet first.
Cephalic (head first)
Breech (pelvis first)
Shoulder (scaplua first)
What are the 3 types of breech presentations
Frank- butt is first, legs extended
Full/complete - fetus sits crosslegged
Footling/incompete - one or both legs are presenting
*frank can result in vag birth all others - c-section
Breech presentation are associated with
Prematurity, placent previa, multiparity, uterine abnormalities (Fibroids), some congenital anomalies such as hydrocephaly.
Shoulder presentation or shoulder dystocia
occurs when fetal shoulders present first with head tucked inside
“turtle sign”
Fetal position
describes relationship of a given point on the presenting part of the fetus to a designated point of maternal pelvis
What are the landmark fetal presenting parts
(O) - Occipital bone = vertex presentation
(mentum [M]) = chin - face presentation
**(sacrum [S]) **- sacrum - breech
(acromion process [A]) - shoulder presentation
In determining fetal positioning the maternal pelvis is divided into what 4 quadrants?
Right anterior, Left anterior, Right posterior, Left posterior
Fetal position is first id’d by presenting part then maternal quad
How to notate position as a 3 letter abbrievation?
- Presenting part is tilted toward Left or Right side of maternal pelvis, L or R
- Presenting part of fetus, O, S, M,D
- Anterior or posterior A or P
LOA most common and most favorable
ROA next
Fetal station
Refers to relationship of presenting part to the level of maternal pelvis ischial spines.
Measured in centimeres and referred to as PLUS or MINUS, depending on above or below ischial spines
Fetal engagement
signifies the entrance of largest diameter of fetal presenting part (usually head) into the smallest diameter of maternal pelvis
*fetus said to be engaged in pelvis when presenting part reaches 0 station.
Engagment is determined by pelvic exam
Uterine contractions
Involuntary, rhythmic, intermittent with period of relaxation. Pause restores blood flow to uterus and placenta
-Responsible for thinning and dilating cervix, then thrusting presenting part to lower uterine.
How would effectment be decribed
Cervical canal 2cm in length
Cervical canal 1 cm in length
Cervical canal 0 cm in length
Cervical canal 2cm in length - 0% effaced
Cervical canal 1 cm in length - 50% effaced
Cervical canal 0 cm in length - 100% effaced
What are the 3 phases of contraction
Increment - build up of contraction
Acme - peak
Decrement - desecent or relaxation of uterine muscle fibers
Uterine contractions are monitored and assessed according to 3 parameters?
Frequency - how often. Measured from begining of one to begining of next
Duration - how long lasts. Measured from begining to end
Intensity -strength. Determined by palpation or measured by internal intrauterine pressure catheter
What are the maternal physiologic responses to labor
HR increase by 10-20bpm
C/o increase by 12-31% during 1st stage of labor and 50% second stage
BP increases to 35mmhg during contractions
WBC increase 25,000 to 30,000
RR increases
Gastric motility and food absorption decrease
Temp rises slightly
Muscle aches and cramps
Blood glucose decrease
What are the physiologic responses of the fetus to labor?
Periodic HR acceleration/decelarations
Decrease in circulation and perfusion
Increase in arterial carbon dioxide pressure
Decrease in fetal breathing movements
Decrease in fetal oxygen pressure
What are the 4 stages of labor?
Dilation
Expulsive
Placental
Restorative
What can affect the length of 2nd stage of labor
PArity, delayed pushing, epideral, maternal body mass, birth weight, pelvis shape, occiput posterior position, fetal station at complete dilation
What is included in active managament during the 3rd stage to prevent death
Admin uterotonic agent
Expulsion of placenta with controlled traction of cord
Uterine fundal massage after placental expulsion
Spontaneous birth of placenta can occur in what 2 ways?
Fetal side (schultz side) - shiny gray side
Maternal side (duncan mechanism)- red raw side
How much blood is lost in
vaginal delivery
c-section
severe?
Vag - 500 ml
C-section - up to 1000ml
Severe = over 1000 ml
What is the purpose of performing a vaginal exam?
-assess amount of cervical dialtion
-% of effacement
-fetal membrane status
-info on presentation, position, station, degree of fetal head flexion and presence of fetal skull swelling or molding
If the initial vag exam is to check for membrane status, what is used as lube?
Water
What is the process of a vag exam?
-Don sertile gloves
-Insert index and middle finger
-Cervix is palpated to assess dilation, effacement, position
-Membranes evaled
Width of cervical opening determines?
Length of cervix detemines?
Width - dilation
Length - effacement
2cm = 0%, 1cm = 50%, oblierated = 100%
How is station assessed in a vag exam?
in relation to maternal ischial spines, which are blunted prominences at mid pelvis
-If presenting part is higher than spines then a negative number is assigned. If presenting part is lower than a positive number is assigned
How are membranes felt during a vag exam?
soft buldge that is more prominent during contraction
What is the priority assessment when membranes rupture
Fetal heart rate first to id decels which might indicate cord compression secondary to cord prolapse
Ruptured membranes increase risk of infection
What are signs of iintrauterine infection
Maternal fever
Fetal & Maternal tacycardia
Foul odor of vag discharge
increase WBC
At what stage of pregnancy do fetal membranes usually rupture
1st stage
How is the test performed to determine if fetal membranes have ruptured
Sample fluid is taking from vag via a nitrazine yellow dye swab to determine fluids PH
-Amniotic fluid is alkaline and turns swab blue/green and pH 6.5-7.5
-Membranes intact if swab remains yellow/green and pH between 5-6
Vag fluid is acidic, amniotic fluid is alkaline
What could be the cause of a false positive for ruptured membranes swab test?
if woman is exp large amounts of bloody show bc blood is alkaline
What are the 3 phases of a contraction
Increment - building up
acme - peak intensity
Decrement - letting down
Assessment of contractions include?
Freq
duration
intesnity
uterine resting tone
What is the mmHg needed for a uterine contraction to cause cervical dilation
30mmhg or more
During active labor what is the contraction intensity?
Resting tone is normally in early labor?
Resting tone is in active labor?
Intensity - 50-80mmHg
Resting tone - early - 5-10mmhg
Resting tone - active 12-18mmHg
When palpating fundus for contraction instensity how would you describe?
Tip of nose
Chin
forhead
Tip of nose - Mild
Chin - moderate
forhead - strong
Leopold maneuvers
method for determining the presentation, position, and lie of fetus through use of 4 specific steps
Involves inspection and palpation of maternal abdomen
What color should amniotic fluid be when membranes rupture
Clear
Amniotomy
disposable plastic hook used to perforate amniotic sac
What does it mean if amniotic fluid is green?
Cloudy or foul smelling?
Green - indicate fetus has passed meconium secondary to transient hypoxia, prolonged pregnancy, cord compression, intrauterine growth restriction, maternal hypertension, diabetes or chorioamnionitis.
Foul smell - infection
Amnioinfusion
introduction of warmed sterile normal saline or Ringers lactate solution into uterus to dilute moderate or heavy meconium to prevent meonium aspiration
Fetoscope
Modified stheoscope attached to headpiece
Pros and Cons of intermittent FHR monitoring
Pro- Women can move around and change position
Con - does not provide how fetus responds to stress. Cannot detect variability and types of decels
How do you determine a baseline with intermittent ausculation?
FHR assessed for 1 full min after contraction.
From then on listening for 30 sec and X2 is sufficent, unless other problems
Where is FHR most clearly heard on fetus body?
where in maternal abdomen?
In breech?
Fetus on back
Maternal ab - lower quad
Breech - at or above maternal umbilicus
How do you ensure the maternal HR is not confused with fetal?
Palpate pt radial pulse simultaneously while FHR is being ascultated through abdomen
For low risk women FHR and contractions should be assessed
q 15-30 mins in active and 5-15 while pushing
as well as before and after vag exam, membrane rupture, medication admin, ambulation
What are the indications for offering women EFM in labor
Receiving oxytocin
epidural
problems related to fetal or maternal health like prolonged ruptured membranes greater than 24hrs). HTN (higher than 150/100) confirmed delay in 1st or 2nd stage of labor or presence of meconium
Continuous external monitoring
2 ultrasound transducers applied to abdomen
1 is called Tocotransducer (pressure sensitive put against fundus) detects changes in uterine pressure
the other transducer records baseline FHR, long-term variability, accels, decels. Positioned midline between umbilicus and symphysis pubis.
What are pros and cons to Continous external monitoring
Pro: good continous data
Cons: mom cant move, cannot detect short term variability
Artifact
Used to describe irregular variations or absence of FHR on fetal monitor record due to result from mechanical limitations of monitor or electrical interference
Continuous internal monitoring
-Usually considered for high risk
Involves placement of spiral electrode on fetal presenting part, usually parietal bone on head, to assess fhr and pressure transducer placed internally within uterus to record contraction
What could be some conditions for continuous internal monitoring
Multiple gestation
decreased fetal movement
abnormal FHR
IUGR
Maternal fever
Preeclampsia
dysfunctional labor
preterm birth
diabetes, HTN
What 4 specific criteria must be met for Continuous internal monitoring to be used
- Ruptured membranes
- Cervical dilation fo 2cm
- Presenting fetal part low enough to allow placement of scalp electrode
- Skilled practionior to insert and place spiral electrode
Umbilical cord blood analysis is a good indicator of
fetal oxygenation and acid-base condition at birth
Normal pH 7.2-7.3
Fetal scalp stimulation or vibroacoustic stimulation is used for and how
indirect method to eval fetal oxygenation and acid-base balance to id Fetal hypoxia
Stimulator applied to womans ab and turned on for 3-5 sec or placing pressure on fetal head. Well oxygenation fetus will respond acceleration fo 15bpm above baseline that lasts at least 15 sec
Pain in
First stage labor
Second stage
is assoc with
1st - ischemia of uterus during contractions
2nd - stretching of vagina, perineum and compression of pelvis
Applachian women
asain, latino, jewish women
Cherokee, hmong and japan women
Applachian women - knife under bed to cut pain in birth
asain, latino, jewish women - request mothers not husbands at birth
Cherokee, hmong and japan women - remain quiet and do not show pain
What are some nonpharmacologic measures for pain in labor?
continous labor support
hydrotherapy
Hypnosis
ambulation/position change
TENS
acupuncture/pressure
attention focus
massage
breathing tech
effleurage - light stroking touch of ab in ryhtym with breathing during contractions
Neuraxial analgesia/anesthesia
admin of analgesia or anesthetic agents, etiher continuously or intermittently, into epidural or intrathecal space to relieve pain.
Systemic analgesia
Use of one or more drugs admin orally, IM or IV, they become distributed throughout body via circulatory system
OPIOIDS
ANTEMETICS
BENZOS
Inhaled analgesics
Inhaled nitrous oxide offers a safe and effective means of labor analgesia
Self administered
Side effects: nausea, vomit, dizzy, dysphoria. No FHR abnormalities reported
Regional analgesia/Anesthesia
& routes
Pain relief w/o loss of consciousness
Usually refers to partial or complete loss of pain sensation below T8-T10 level of spinal cord
Epidural block
Combo spinal-epidural
Local infiltration
pudendal block
Intrathecal
General anesthesia
reserved for emergency C-section when not enough time for spinal or epidural
Complication: fetal depression, uterine relaxation, maternal vomit and aspiration.
