OB Exam 2 - Labor and Birth Process

Definition of Labor

Uterine contractions that result in cervical change

5 Ps

1.) Passenger (fetus and placenta)

2.) Passageway (birth canal)

3.) Powers (contractions)

4.) Position (of mother)

5.) Psychological response

Fetal presentation

• the part of the fetus that enters the pelvic inlet and leads through he birth canal during labor

  • Cephalic: presenting part is the occiput (vertex)

  • Breech: presenting part is the sacrum

  • Shoulder: presenting part is the scapula

Fetal lie

The relation of the long axis (spine) of the fetus is to the long axis (spine) of the mom

Biparietal diameter

largest part of baby’s scalp

Fetal position

Relationship of a reference point of the presenting part of the 4 quadrants of the pregnant clients pelvis

Occiput anterior (OA)

The ideal position for birth; head down, facing mom’s back, chin tucked

Occiput posterior (OP)

This position is not what we want  - baby is face up and face might get bruised as it will be pushing against mom’s pelvis and mom will feel back pain.

Fetal station

the pressure of the degree of descent of the presenting part of the fetus through the birth canal

Minus station

behind the ischial spines (farther towards mom’s head)

Plus station

past the ischial spines (closer to mom’s feet)

Station number that corresponds with engagement

0 station

+4/+5 station

baby is being born (you can see the head)

Contractions

When the muscle of the uterus tighten up then relax

Cervical effacement

• thinning of the cervix

• may be described as softening of shortening

• caused by contractions and pressure from the fetal head

• documented with percentages

Average cervical length

4-5 cm

Cervical dilation

• opening of the cervix

• cervix is pulled upwards the fetus is pushed downward

• occurs along with effacement

• progresses fro closed to completely dilated at 10 cm

1st stage of labor

onset of regular uterine contractions:

• Latent: 0-6cm

• Active: 6-10cm

• Transitional: fully dilated, really strong, hormonal response, guttural “ugh” from patient

2nd stage of labor

time of full cervical dilation to birth of baby

3rd stage of labor

delivery of baby to delivery of placenta (usually about 10 min)

4th stage of labor

begins with delivery of placenta and last about 2 hours after birth

• recovery time, vitals every 15 min, fundal checks, making sure patient isn’t bleeding too much.

7 cardinal movements of Labor

1.) Descent: point at which the fetal head move into pelvis through pelvic inlet at -5 station and descends towards the ischial spines.

2.) Engagement: when the fetal head has reached the ischial spines at 0 station (fetal head is engaged)

3.) Flexion: fetal head flexes at it accommodates to the curvature of the sacrum (chin goes towards chest)

4.) Internal rotation: fetal head rotates to align the long axis of the fetal head with the long axis of the pelvis outlet, thus facilitating passage of fetal head through the outlet (followed by rotation of the shoulders)

5.) Extension: extension of fetal head; facilitates movement through mother pubic bone.

6.) External rotation: baby’s head rotates naturally to align with shoulders

7.) Expulsion: medical term for finishing delivery

Fetal heart rate

reliable and predictive information about the condition of the fetus related to oxygenation

• normal FHR is 110-160 bpm

Gate Control Theory of Pain

• This theory proposed that our brain contains neurological gateways that decide which pain signals get to pass through and which are kept out. 

• If you flood the cate (CNS ) with other sensory input (music, moody lights, etc.) then there won’t be as much room for the pain

• Ex: herding sheep through a gate in a fence, so only a few sheep can get through at a time.

• Nonpharmacological strategies: 

  • Aromatherapy, music, imagery, focal points (photos)

  • Breathing techniques

  • Effleurage (light massage)

  • Counter pressure or firmer massage

  • Walking, rocking, position changes

  • Applications of hear, cold

  • Water therapy

  • Acupressure and acupuncture

  • Biofeedback hypnosis

  • TENS unit (low to high intensity)

Labor and birth pain: Stage 1

• Uterine ischemia during contractions

• Distention of lower uterine segment

• Stretching of cervical tissues and it effaces and dilates

• Pressure and traction on adjacent structure

• Referred pain to the back, thigh, and elsewhere

• Typically pain free between contractions

Labor and birth pain: Stage 2

• Distention and tractions on peritoneum and uterocervical junction

• Pressure against the bladder and rectum

• Stretching and distention of perineal tissues and the pelvic floor to allow fetal passage

• Laceration of soft tissues (cervix, vaginal canal, perineum)

• Pain is more localized and may be sustainable between contraction

• Pushing may reduce perception of pain

Labor and birth pain: Stage 3

•  3: 

  • Afterpains: mimic ear stage one pain 

  • Expulsion of placenta is minimally painful

  • Uterine cramping during involution (which get worse with every baby you have; after being stretched out every time it is harder and harder for the uterus to get back down to size

What can influence a patient’s perception of pain?

• Culture, ethnicity, behavioral expectations

• Age, parity, previous experiences with pain

• Fear, lack of knowledge, belief that pain means suffering (increases pain)

• Knowledge, support, belief that pain is natural (increased pain)

Physiologic factors influencing pain

• Pattern and efficiency of contractions

• Fatigue, stress

• Fetal size and position

• Speed of fetal descent

• Maternal position and movement

• Release of beta-endorphins

The influence of anxiety on pain response

• Anxiety can make pain so much worse and effectively stop labor

• You can see it when an anxious patient gets an epidural and they can finally relax because of the reduced pain, the labor starts to progress more.

Epidurals

• Local anesthetic with or without opioid agonist

• Injected into epidural space 

• Anesthesia from T10-S5 (vaginal birth) or T8-S1 (C-section)

• Catheter in place until after delivery

• Med controlled by pump

Spinals

• Local anesthetic with or without opioid agonist

• Injected into subarachnoid space

• Anesthesia from hips (vaginal birth) to nipples (C-section)

• Last 1-3 hours

Contraindications for epidurals and spinals

• Active or anticipated hemorrhage

• Preexisting maternal hypotension

• Anticoagulant therapy/bleeding disorder

• Infection at or near injections site

• Allergy to drug

• Maternal refusal or inability to cooperate

Nursing considerations for epidurals and spinals

• Hypotension, altered breathing patterns may lead to reduced perfusion of placenta; otherwise, no systemic impact to fetus

• Additional risks: infection, leakage of CSF, bladder and uterine atony, itching, toxicity

• May cause ineffective pushing, increased risk for forceps or vacuum-assisted birth prolonged 2nd stage of labor

• Possible unsafe ambulation

• Advantages: patient is alert, comfortable, may be able to labor down

Nursing care for epidurals and spinals

• Secure informed consent

• Administer IV fluid bolus before procedure

• Position and help support patient

• Monitor maternal Vitals (every 5 min)

• Monitor FHR

• Document procedure

• Monitoring and repositioning patient afterwards.

Analgesic administration

Analgesic alleviate pain or increase pain threshold, without loss of consciousness

• IV or IM

• Readily cross placenta and can have effects on the baby (lasts hours-days)

• Best in early/active labor

• PCA pump

• AE: nausea, vomiting, dizziness, urinary retention, respiratory depression

Opioid Agonists

• Demerol, fentanyl

• stimulate kappa+mu opioid receptors

• may inhibit uterine contractions

Opioid Agnost/antagonist

• Stadol, nubain

• stimulate kappa, block or weakly stimulate mu receptors

• disadvantage = ceiling effect for respiratory depression

Opioid Antagonist

• Narcan

• reverses respiratory depression in mom or baby

• also reverses stress induced natural endorphins

FHR Patterns: Category I (Reassuring)

• Baseline norm (110-160)

• moderate baseline variability

• present or absent accelerations

• present or absent early decelerations

• no late or variable decelerations.

FHR Patterns: Category II

• includes all patterns that fall into category I or III

• may be responsive to interventions

• may be contextual (look at other factors such as meds given to mom?)

FHR Patterns: Category III (Non-reassuring)

• Baseline FHR variability absent (flat line)

• fetal bradycardia and/or recurrent late or variable decelerations

• sinusoidal patterns (gentle waves, worst FHR pattern to see)(Ask if meds have been given, pattern is an emergency)

Decelerations

caused by parasympathetic response; may be benign, may be abnormal categories (early, late, variable, or prolonged)

Early Decelerations

• Apparent gradual decrease in baseline FHR 

  • mirrors contraction pattern - FHR begins to drop as contraction starts and FHR reaches baseline as contractions ends

• occurs in response to fetal head compression

• benign finding (no intervention needed)

• document and continue to monitor.

Late Decelerations

• Apparent gradual decrease in baseline FHR

  • FHR lags behind uterine contraction - FHR begins to drop as contraction starts, reaches lowest point as contraction peaks, and reaches baseline as contraction ends. 

• Occurs in response to factors that disrupt oxygen transfer to the fetus (uteroplacental insufficiency, maternal hypotension, uterine tachysystole, etc.)

• Abnormal finding associated with hypoxemia

• Ominous is uncorrected or when associated with absent/minimal variability

• Interventions: repositions, O2, IV bolus, discontinue pitocin, internal monitoring

• Notify provider, may require rapid delivery

Variable Decelerations

• Apparent, abrupt decrease in baseline FHR

• Occurs during any uterine contractions phase (including resting)

• Occurs in response to umbilical cord compression 

• Occasional variability has little clinical significance

• Recurrent variability causes repetitive interruptions in fetal oxygen

• Interventions: repositioning, O2, discontinue pitocin (contractions are too close together in these decels so stopping a drug that is causing the contractions to speed up is good), assist with speculum exam to assess for cord prolapse, assist amnioinfusion. 

VEAL CHOP

Variables —-> Cord (cord gives oxygen and variable decels involve disruption in oxygenation

Earlies —-> Head (fetal head compression in early decels)

Accelerations —->  Okay (accelerations are good so yay!)

Lates —-> Placenta (late decels are in response to disruption of oxygen transfer - placental issues)

Frequency of uterine contractions

2-5 contractions per 10 minutes or 1 contraction every 2 minutes, as labor progresses contraction frequency gets closer to that 2-5 range.

Duration of contractions

each contraction lasts from 45-80 seconds; usually no more than 90 (tetany)

Strength of contractions

evaluation through palpation or internal monitoring or pressure

Resting tone of uterus between contractions

uterus should palpate as soft

Relaxation time between contractions

60 or more seconds in 1st stage, 25 or more in 2nd stage

Assessing FHR variability

• Variability described at irregular fluctuation in baseline FHR

  • Excluded acceleration or decelerations

  • Measured in BMP per single heart beat cycle

Absent variability

• abnormal or indeterminate

• undetectable

Minimal variability

• abnormal or indeterminate

• Minimal: undetectable to ≤ 5bpm

Moderate variability

• normal; highly predictive or normal fetal acid-base balance

• 6-25 bpm

Marked variability

• abnormal or indeterminate

• > 25 bpm

Care of Maternal Hypotension

• Bolus of IV fluids helps increase intravascular volume

• Associated is prolonged decels

• Monitor for hypotension with an epidural

• Meds that cause hypotension: gentamycin, cefazolin, nifedipine, mag sulfate

Umbilical Cord Prolapse

• Cord lies below the presenting part of the fetus (cord comes out before baby)

• Major risk  = compression of cord by the fetus

• Contributing factors: long cord, malpresentation (breech), fetus not engaged in pelvis

• Nurse’s role: keep fetus head off cord, protect cord from injury

• Vaginal birth is no longer possible, intervention is rapid/emergency C-section delivery

• Sudden decrease in FHR or sudden gush of fluid means we need to examine vagina for pulsation or cord; don;re remove fingers from patient and keep head off cord.

• Breathing techniques

• Stage 1: used to relax; slow paced breathing tailored individually

• Stage 2: helps with pushing; avoid holding breath, slowed controlled exhale is better

• All breathing patterns begin and end with a deep relaxing cleansing breath; increased relaxation and boosts O2 for mom and baby

• Watch for hyperventilation

Precipitous Delivery

• Precipitous labor: labor lasting less than 3 hours from onset of contractions until birth (normally not 1st baby)

• Increased risk for hemorrhage and perineal damage (labor is so fast that it doesn’t allow the tissues to stretch properly). 

• Baby may have bruised face

Rupture of Membranes

• PROM (Prolonged rupture of membranes) = spontaneous rupture of amniotic sac, leakage of fluid, before onset of labor

• PPROM = occurs before 37 weeks

• At risk for urogenital tract infection so assessment is important 

• Chorioamnionitis: uterine infection (fever, tachycardia, increased respiration, pain (cramping),  hypotension, uterine irritability, color/smell to amniotic fluid) 

• Amniotomy = AROM: Assisted rupture of membranes; baby needs to be at 0 station

Augmentation of Labor

Similar to induction but after labor has already begun

Methods of Cervical Ripening

Cytotec and cervidil

Tocolytic Administration

• Used to suppress uterine activity (greater than 34 weeks)

  • We can’t stop the baby from being born but we can delay it

• Magnesium sulfate = most common; may now slow contractions but it’s neuroprotective

• Terbutaline and Nifedipine also used

• Gain of 48 hours is the usual/best outcome

• Provides time to administer glucocorticoids for fetal lung development

Corticosteroid Administration

• Promotion of fetal lung maturity by simulating surfactant production

• Antenatal glucocorticoids given IM

• Recommended for women 24-34 weeks who are at risk for preterm birth

Meconium Aspiration

• Greenish staining, thin or thick with particulate (stool)

• May be from normal physiologic function (maturity, breech), related to hypoxia (induced sphincter relaxation), vagal stimulation (from umbilical cord compression)

• Major risk is meconium aspiration syndrome and subsequent severe pneumonia

• Can be caused by postterm pregnancy

Preterm timeframe

after 20 weeks, before 37 weeks (classification of very, moderate, or late preterm)

Preterm labor

regular contractions accompanied by cervical change before term date

Preterm birth

Any birth occurring within the preterm timeframe 

• 75% spontaneous

  • Causes are multifactorial and poorly understood

  • Not possible to predict who will be preterm

  • Infection is only factor to have definite association

• 25% indicated → pregnancy too risky to continue

What do we see in preterm labor?

• Contractions may not be strong or frequent

• Pain limited to increased cramping or pressure because baby is small

• Cervix doesn’t need to dilate as much for preterm birth

• Preterm labor can change abruptly (patient stops having labor signs and goes home or they spontaneously deliver)

Risk factors for preterm labor:

• History of prior preterm birth

• Race

• Multiple babies

• Second-trimester bleeding

• Poverty

• Lack of education

• Living in a disadvantaged neighborhood

• Lack of access to prenatal care (disadvantaged neighborhoods fall into this category)

• Possible genetics

Predicting premature labor

• Measuring cervical length

  • Greater than 30mm = unlikely to deliver prematurely 

• Fetal fibronectin test (fFN):

  • Presence in sample may indicate placental inflammation

  • High value = highly unlikely to go into labor

  • Low value = doesn’t mean much

Primary preventions for preterm labor

• Address risk factors 

• Progesterone supplementation if women has history of shortened cervix

• Lifestyle modifications and increased monitoring

• Educate about s/sx

Interventions for preterm labor

• Cervical dilation of 4cm will likely lead to inevitable preterm birth

• Can still give some meds is time permits (mag sulfate, steroids)

• Women can rapidly dilate and progress to birth

• Small fetus = full dilation not needed

• Prepare equipment and personnel

Induction of labor

• Induction should NEVER be out of provider or patient convenience; it increase risk of infection and hemorrhage

• Need induction for postterm pregnancies

• What to do?

  • Give cervical ripening agents (cytotec, cervidil)

  • Balloon catheter → inflating the balloon creates pressure which signals the uterus to contract; balloon is deflated at 4-5cm

  • Pitocin drop and rupture or membranes if needed