L&D Exam 1

5 Ps

passenger, passageway, parts, powers, psyche

passenger

fetal head, fetal attitude, fetal lie, fetal presentation

fetal head elements that allow movement thru birth canal

fontanelles - have 2 (anterior and posterior - posterior closes after 1-2 mo, anterior is later), gaps “soft spots” between skull bones

sutures - fibrous flexible joints connecting skull plates. form to bone by adulthood

fetal attitude

relation of fetal parts to each other. can be vertex (full flexion), sinciput (moderate flexion), brow (partial extension), face (complete extension)

fetal lie

relationship of longitudinal axis of fetus to longitudinal axis of mother

• longitudinal = baby’s spine parallel to mother. can be cephalic (head first) or breech (feet first)

• transverse = baby’s spine perpendicular to mother, requires cesarean

• oblique = diagonal, will change before labor

fetal presentation

fetal body part presenting to maternal pelvis

• vertex (head first), breech (feet first), or shoulder first

parts - station

location of baby’s head in relation to invisible line drawn between two ischial spines of pelvis, -4 to +4. negative numbers = baby’s head above station, 0 = at station, positive numbers = baby’s head below station

parts - position

position of fetus relative to anterior, posterior or sides of maternal pelvis

• first letter - which side of maternal pelvis is the presenting part on? (L or R)

• second letter - which fetal part is presenting? O = occiput, M = mentum, S = sacrum

• third letter - orientation of presenting part relative to maternal pelvis anterior (A), posterior (P) or transverse (T)

OA = yay (preferred birthing position); OP = ouch (more difficult/painful birth)

powers - cervix

effacement (thinning of cervical walls) and dilation (enlargement of cervical canal to ~10cm

described by 3 numbers - % effaced, cm dilated, and station

electronic fetal monitoring (EFM)

provides a continuous tracing of fetal heart rate (FHR) allowing its characteristics to observed and evaluated

objectives of EFM

prevent fetal injury that might result from disruption of normal fetal oxygenation during labor

recognize specific features of the FHR that suggest a normal acid/base balance, and identify patterns that are indicative of impending or existing fetal acidemia so that appropriate interventions may be initiated

benefits of EFM

• evaluate fetal well-being

• useful in diagnostic testing

• help evaluation labor progress

risks of EFM

• supine postural hypotension

• intrauterine perforation and infection (with internal monitoring)

• decreased personal interaction (attention paid to machine)

• mother unable to ambulate or change position

influences on FHR - utero-placental unit

• at term, 10-15% of maternal CO (500-750 mL/min) perfuses the uterus each minute

• oxygenated blood from mother is delivered to intervillous space (where maternal-fetal exchange of O2, CO2, nutrients, waste products, and water occur) in placenta via uterine arteries

influences on FHR - oxygenation to fetus

dependent on:

• adequate oxygenation of mother

• adequate blood flow to placenta

• adequate uteroplacental circulation

• adequate umbilical circulation (umbilical cord has 2 arteries which carry deoxygenated blood from fetus to mother and 1 vein which carries oxygenated blood to fetus)

• fetus’s own innate ability to initiate compensatory mechanisms to regulate FHR

influences on FHR - parasympathetic stimulation

vagal nerve stimulation slows FHR and helps maintain variability (which develops at 28-30 wk gestation)

influences on FHR - sympathetic stimulation

increases FHR (occurs thru release of norepinephrine. may be stimulated during hypoxemia

influences on FHR - fetal mechanisms

CNS, baroreceptors, chemoreceptors, hormonal regulation

fetal/placental reserve

the reserve of O2 available to the fetus to withstand the transient changes in blood flow and oxygen during labor

auscultation of FHR

• performed with fetoscope or doppler; determine fetal presentation/position using Leopold’s maneuvers

• listen before, during and after a contraction

• guidelines vary for labor stage 1/2 and low/high risk pregnancies

category I FHR

normal. strongly predictive of well-oxygenated, nonacidodic fetus with normal acid-base balance

category II FHR

indeterminate. not predictive of abnormal acid=base status, but not I or III. require evaluation and continued monitoring

category III FHR

predictive of abnormal fetal acid-base status and requires prompt evaluation and

FHR pattern interpretation

• FHR baseline - 110-160 bpm, what is the variability?

• periodic (with contractions) and episodic (without/between cchanges - accelerations and decelerations.

baseline FHR (how to calculate)

mean FHR rounded to increments of 5bpm during a 10 minute window, excluding accelerations, decelerations or marked variability

baseline variabiliy

• fluctuations in baseline FHR that are irregular in amplitude and frequency

• most important predictor of fetal oxygenation during labor; presence shows interaction between sympathetic/paraympathetic NS and shows that fetus is not in metabolic acidosis

  • absent - amplitude undetectable

  • 
    

FHR accelerations

visually apparent abrupt increases lasting less than 30 seconds above baseline FHR

• 15 beats above baseline for 15 sec (or 10×10 for fetus <32 weeks)

predictive of adequate fetal oxygenation and absence of fetal acidemia, often

FHR decelerations

transitory decreases in FHR baseline. may be early, variable, late or prolonged

classified according to shape, timing and duration in relation to the contraction

• recurrent = occurring in 50%+ of uterine contractions in a 20 min period

• intermitent = occurring in <50% of uterine contractions in a 20 min period

early decelerations

• gradual decrease in FHR that mirrors uterine contractions (UC) - nadir (lowest point) aligns with peak/acme of contraction

• associated with head compression (from stimulation of fetal vagus nerve)

• considered benign - no intervention necessary

variable decelerations

most common deceleration - abrupt decrease in FHR (onset to nadir <30 seconds)

• decrease is 15bpm below baseline lasting 15 sec-2 min

• may be episodic or periodic

• associated with umbilical cord compression or occlusion

late decelerations

gradual decrease in FHR (onset to nadir 30 seconds) below baseline, with nadir occurring after peak of UC

• indicates transient or chronic uteroplacental insufficiency - decreased availability of O2

nursing actions for intrauterine resuscitation

objective: improve fetal oxygenation/uteroplacental perfusion while assessing and eliminating the stressor

• maternal position change

• administer fluid bolus

• ad

prolonged deceleration

decrease in FHR 15bpm below baseline lasting 2 min - 10 min from onset to return to baseline. indicates:

• profound change in fetal O2

• interruption of uteroplacental perfusion

• interruption of umbilical blood flow

• vagal stimulation

evaluating uterine activity and contractions

essential part of FHR interpretation, must be accurate

factors to evaluate:

• frequency

• duration

• intensity

• resting tone

• tachysystole = contractions occurring too close together, insufficient fetal oxygenation

studies show that continuous EFM -

• is associated with an increase in operative deliveries and c/s

• is associated with decrease in neonatal seizures

• not associated with lower cerebral palsy rates or neonatal death rates

main function of estrogen during pregnancy

• vascularity and vasodilation

• enlarges/maintains uterus, develops placenta, prepares breasts for lactation

• helps mature fetal organs

main function of progesterone during pregnancy

• relaxes smooth muscle and stimulates respiratory function

GTPAL

G - Gravida (total # of pregnancies, regardless of duration, including current)

T - # of term infants born (≥ 37 wks)

P - # of preterm infants (20-37 wks)

A - # of abortions (spontaneous or induced)

L - # of currently living children (note: twins counts as 1 pregnancy, 2 babies)

intrapartum physical assessment

• birthing parent VS

• uterine assessment - contraction onset/frequency/duration/intensity, palpation and EFM

• cervical assessment - dilation, effacement, position, consistency, fetal presenting part, station, membrane status

membrane status - SROM

spontaneous rupture of membrane - amniotic sac breaks on its own

membrane status - AROM

artificial rupture of membrane - provider ruptures amniotic sac to speed labor

membrane status - PROM

premature rupture of membrane (PPROM if occurs before 37 weeks of gestation, high risk)

diagnostics for membrane status

• nitrazine swab - test that indicates presence of amniotic fluid

• ferning - pattern made by dried/crystallized urine which indicates ruptured membrane

• pooling - visible accumulation/collection of amniotic fluid in the vagina

Leopold’s maneuevers

systematic method of abdominal palpation used in obstetrics to determine the position, presentation, and lie of a fetus inside the uterus

FHR devices

external - doppler measures FHR, tocodynameter measures uterine contractions

internal - IUPC (intrauterine pressure catheter) and/or FSE - fetal scalp electrode

principles of care to promote normal birth

1. Labor begins on its own

2. Freedom of movement throughout labor

3. Continuous labor support

4. No routine interventions

5. Non-supine positions for birth

6. No separation of parent/baby after birth and unlimited breastfeeding opportunities

APGAR

newborn health assessed at 1 min and 5 min, then again at 10 min if below 7. all elements assessed on 0-2 scale

A - appearance (skin color)

P - pulse (HR)

G - grimace (reflexes and irritability)

A - activity (muscle tone)

R - respiration (breathing rate/effort)

visceral pain

diffuse/poorly localized, dull and aching pain, felt more during first stage of labor

somatic pain

very localized, sharp and intense pain, felt more during transition phase of first stage and during stage two of labor

neuraxial - standard epidural

• injected into epidural space

• is a smoother experience with adjustments possible

• slower onset, ideal for early labor

neuraxial - combined spinal epidural (CSE)

• injected into CSF then epidural space

• quick onset plus prolonged dosing option, less motor block

• more hypotension and fetal bradycardia

• ideal for early and active labor

neuraxial - spinal

• injected into CSF only

• quick onset, less motor block

• more hypotension and fetal bradycardia

• ideal for C-sections (quick onset, time limited)

most common adverse effect of neuraxial anesthesia

maternal hypotension which can lead to fetal bradycardia

well-established side effects of epidurals

itching - treat with naloxone

hypotension - treat with vasopressor

longer 1st and 2nd stage of labor

need for forceps or vacuum delivery

fever

common medications in each phase of first stage of labor

latent - sedatives

active - opioids, neuraxial

transition - neuraxial