OB Exam 2

labor

function by which the products of conception (fetus, amniotic fluid, placenta, membranes) are separated and expelled from the uterus through the vagina into the outside world

true labor

• cervix softens, effaces and dilates and moves anteriorly

• contractions become “longer, stronger and closer together”

• regular contraction pattern

• intensity increases with walking or standing

• felt in lower back and radiate to lower abdomen

• continue to increase in intensity despite comfort measure or position changes

false labor

• usually little or no cervical change 

• cervix often stays in poster position 

• contractions have irregular pattern and intensity does not increase with time 

• contractions are easily interrupted with medications, walking or position change 

• felt in back or upper fundal area

labor initaition (patient) 

• uterine muscles stretch releasing prostagladins 

• pressure on cervix from fetus stimulates release of oxytocin (Ferguson reflex

• estrogen/progesterone ratio shifts so that estrogen stimulates contractile response of uterus and drop of progesterone increases oxytocin 

  • eestrogen= increased contractions

  • progesterone = relative decrease means oxytocin no longer inhibited meaning more contractions

• dramatic increase of oxytocin during labor

labor initiation (fetal)

• placental aging and deterioration

• cortisol production 

  • made in the fetal adrenal gland and stimulates labor onset by acting on placenta to reduce progesterone formation and increase prostaglandin

• prostaglandin produced by fetal membranes and uterine decidua stimulate contractions 

powers

uterine smooth muscle contractions with force generating capacity 

• frequency

• duration

passengers

fetus; affected by size, presentation, position, presenting part, degree of flexion (attitude) and placenta

passage and position

bony boundaries of the pelvis and position of the patient in labor

psyche

patients emotional state determines their response to labor and influences physiological functioning

• fear from past experiences

• hospital as point of no return

• unwanted pregnancy? high expectations?

• sterss hormones can stall labor

LISTEN EDUCATE SUPPORT

strength of contraction (powers)

• pacemaker located in fundus because greater number of myometrial cells located there 

• normally 30-50mmHG/UC necessary for effective labor 

• adequate labor contractions= montevideo units (MVU’s) >200 mmHg total across contraction per 10 minutes (if IUPC)

• desire no more than 5 UCs in 10 minutes (MVU’s <280 mmHG)

measuring powers

• palpation

• external tocodynamometer (gives the frequency and duration but not the intensity)

  • affected by patient habitus and proper placement

• IUPC- measures MHG exerted by each contraction

  • associated with infection, uterine perforation, trauma

tachysystole

greater than 5 contractions in 10 minutes 

hyperetonus

contractions lasting longer than 2 minutes in duration

cephalopelvic disproportion

mismatch between size and/or shape of the fetal head and size and/or shape of the pelvis, making it difficult for the baby to pass through the birth canal

gynecoid 

normal pelvis for individuals assigned female at birth with an incidence of 50%

round or transverse oval shape, all diameters are adequate 

most ideal for space

android

pelvis for individuals assigned male at birth with an incidence of 20%

heart of wedge shaped

reduced in all diameters

arrest of labor is common

anthropoid 

ape like pelvis with an incidence of 25%

long anteroposterior oval shape

OP presentation is common 

platypelloid

flate with an incidence of 5%

transverse oval shape

delay of descent at inlet is common and c/s is common

fetal lie

reference to maternal spine

• longitudinal

• transverse

• oblique

fetal presentation 

• cephalic: vertex, military, brow, face 

• breech: complete, frank, footling 

• shoulder 

fetal attitude

• flexion (vertex) - everything crossed in

• extension- neck and arms pushed back

fetal position

occiput, sacrum, mentum (chin)

anterior 

fontanelle that is closed by 18 months and is diamond 

posterior

fontanelle that is closed by 6-8 weeks and is triangle

engagement

when the widest diameter of the presenting part has passed the inlet, usually 0 station

floating

when presenting part is entirely out of the pelvis and freely movable in the inlet

cardinal movements 

• engagement and descent 

• flexion 

• internal rotation 

• extension 

• restitution 

• external rotation 

• expulsion 

5 P’s interventions 

• facilitate effective uterine contractions 

• minimize risk of infection/complication

• facilitate maximum pelvic capacity 

• facilitate fetal cardinal movements with position changes 

• minimize anxiety and fear associated with labor 

• maximize coping strategies and knowledge and understanding

initial labor admission

• review of systems

• urinary protein and glucose

• leopold’s maneuvers to determine fetal position

• fundal height

• signs of domestic abuse and support

• signs of preeclampsia

Risk factors:

• prior OB history

• current pregnancy info

• prenatal

Labor Sx and Fetal Status:

• Oxygenation of patient and fetus

• assessment of labor tolerance - patient and fetus

labor continued assessment 

• vitals checked every hour while in active labor 

• I/O every 4 hrs 

• contraction pattern - assess by palpation, even with IUPC- confirm uterine relaxation 

• cervical exam- dilation, effacement, fetal station

• ROM- time,color, amount, odor 

• bleeding, discharge 

hyperventilation

• common with anxiety and occasionally occurs when utilizing relaxation breathing techniques 

• symptoms: lightheadedness, dizziness, tingling of fingers, spasms in hands or feet, circomoral numbness

Results: respiratory alkalosis 

interventions: 

• replacement of bicarbonate ion by rebreathing CO2

platelets (labor)

decreased thought to be due to hemodilution

WBCs(labor)

increase to 25,000 considered normal

same response as strenuous exercise

first stage of labor 

• assist with positioning 

• monitor maternal/fetal status 

• integrate support persons into plan of care doulas, friends, family, partners 

• implement pain management techniques/meds 

• monitor I/O

• assist with infection prevention- know your patient’s STI, GBS lab status  

second stage of labor

• encourage rest during latent phase

• optimize oxygenation (open glottis pushing, side-lying position, push every other UC)

third stage of labor

• facilitate bonding

• observe for signs of separating placenta

• monitor for and prevent increased bleeding

• expectant vs active management (pitocin, cord traction, fundal massage)

• inspect placenta for abnormalities

signs of placental separation

• lengthening of cord

• change in shape of fundus from discoid to globular

• gush of blood

shiny schultz 

fetal side of placenta 

dirty duncan

maternal side of placenta

fourth stage of labor

newborn:

• support trasition to extrauterine life

• APGAR, initial assessment, meds, etc.

maternal:

• monitor for signs of excessive bleeding

  • VS/fundal/lochia assessments- q15 ×4, q30×2 until stable

  • QBL- weigh pads (1gm=1ml)

  • oxytocin IV or IM

version

turning of fetus from one presentation to another (usually from breech/shoulder to vertex)

version prereqs

• confirm >=37 weeks

• ultrasound: placenta, cord, fluid, position, uterine anomalies

• reactive NST to confirm fetal well-being

• informed consent

• tocolysis (terbutaline) to relax uterus

version postprocedure 

• assess for abruption, rupture, PTL, AFE, fetal distress 

• monitor FHR, contractions for 1hr or until stable 

• RhoGam if mom is Rh- 

version contraindications

• uterine anomalies (ex: bicornuate uterus)

• lavor contractions - can’t do with contracted uterus

• 3rd trimester bleeding (ex: previa)

• multiple gestation

  • internal version can be done for 2nd twin

• oligohydramnios

• evidence of uteroplacental insufficiency

• nuchal cord

• prior c/s of significnat uterine surgery

• obvious cephalopelvic disproprortion

1st stage pain

visceral

• cervical dilation and effacement

• ischemia of uterine muscles 

• stretching of LUS 

• pressure on pelvis, bowel, bladder 

2nd stage pain

somatic pain 

• distention of vagina 

• distention and stretching of perineal tissue 

• ischemia of uterine muscles 

• pressure on pelvis, bowel and bladder 

nonpharacologic pain management

• cognitive: relaxation, patterened breathing, imagery, hypnosis

• cutaneous: massage, warmth, hydrotherapy, positional assistance (birthing/peanut ball), rockinging/swaing

nitrous oxide

laughing gas

• 50% oxygen 50% nitrous oxide

• commonly used in midwives and homebirths

narcotics- fentanyl and butorphanol 

opioid agonist 

• increases pain threshold 

• may increase or decrease uterine contractions 

• may cause drowsiness 

• cross placental barrier—→ administer during contraction to minimize fetal effect 

• can cause sinusoidal appearing FHR pattern 

IV fentanyl

advantages:

• strong narcotic

  • decreases severe pain

• short acting

  • effect worn off in less than 1 hr

• cardiovascular stability

  • BP usually does NOT drop

• moderate sedation

• minimal nausea

• minimal newborn effects

• can be given right up to time of delivery

• inexpensive

disadvantages:

• strong narcotic

  • can cause respiratory depression narcan

• short acting

  • needs to be repeated frequently

• itching is common

agonist-antagonists 

• butorphanol tartrate (stadol) or nalbuphine hydrocholride (nubain) 

• good analgesia with less respiratory depression and N/V

agonists

• promethazine (phenergan)

• decrease anxiety and apprehension, increase sedation and reduce nausea and vomiting

• may potentiate narcotic- help them work more effectively (morphine)

sedatives

• zolpidem (ambien) or secobarbitol (seconal)

• provide sedation or sleep and reduce tension and fear

• cross placenta and may affect newborn up to 12-24 hours