Labor&DeliveryN2

• Factors that affect and define the labor and birth process - the "Five Ps"

  • Passageway (birth canal)
  • Passenger (fetus and placenta)
  • Powers (contractions)
  • Position (of the woman)
  • Psychological response
• Passageway


  Birth canal
• Pelvic Shape


  • Gynecoid pelvis
  • Anthropoid pelvis
  • Android pelvis
  • Platypelloid (flat) pelvis
• Passageway


  • Bony pelvis – size and shape must be adequate to allow the fetus to pass through it
  • Pelvic inlet
  • Mid-pelvis
  • Pelvic outlet
  • Soft Tissues - Cervix, Pelvic floor muscles, Vagina
• Passenger


  • Fetus with the placenta
• Fetal head


  Largest fetal structure
• Bones of the fetal skull

  • Two frontal bones
  • Two parietal bones
  • Occipital bone
• Sutures


  Space between the bones
• Fontanelles


  Intersection of the sutures
• Molding


  Overlapping of bones during the birthing process
• Fetal attitude


  Referring to the posturing of the joints
• Flexion


  Most common fetal attitude, presents smallest fetal skull diameter
• Extension


  Tends to present larger fetal skull diameter
• Lie


  Relationship of the fetal long axis to the maternal axis
• Fetal lie


  • Longitudinal – long axis of the fetus is parallel to that of the mother
  • Transverse – fetal long axis is horizontal and therefore perpendicular to the maternal axis - will not accommodate vaginal birth
• Fetal presentation

  • Cephalic – head first
  • Vertex (occipital portion)
  • Military
  • Brown
  • Face
  • Breech – pelvis first
  • Frank breech
  • Complete breech
  • Single footling breech
  • Double footling breech
  • Shoulder – scapula first
• Fetal position

  Relationship of a given point on the presenting part of the fetus to a designated point of the maternal pelvis
• Fetal position labels

  • Right (R) or left (L) – which side of the maternal pelvis
  • Occiput (O), sacrum (S), mentum (M), or scapula (Sc) – presenting part of the fetus
  • Anterior (A), posterior (P), or transverse (T) – the part of the maternal pelvis
• Station

  • Station 0 being at the level of an imaginary line at the level of the ischial spines
  • Minus stations superior to the ischial spines
  • Plus stations inferior to the ischial spines
• Fetal engagement

  Entrance of the largest diameter of the fetal presenting part (usually the head) into the smallest diameter of the maternal pelvis
• Cardinal movements of labor

  • Engagement
  • Descent
  • Flexion
  • Internal Rotation
  • Extension
  • External Rotation (Restitution)
  • Expulsion
• Powers

  1. Uterine contractions cause effacement (shortening and thinning of the cervix) during the first stage of labor

  2. Uterine contractions cause dilation of the cervix (enlargement and widening of the cervical opening and canal) that occurs once labor has begun and dependent on the pressure of the presenting part

  3. Involuntary urge to push and voluntary bearing down in second state of labor helps in the expulsion of the fetus
• Cervical canal

  • Reduces in length from 2 cm to a paper-thin entity
  • Cervical dilation increases from less than 1 cm to approximately 10 cm – when fully dilated it is no longer palpable
• External cervical os

  • Closed – 0 cm dilated
  • Half open – 5 cm dilated
  • Fully open – 10 cm dilated
• Position

  • Client should engage in frequent position changes during labor to increase comfort, relieve fatigue, and promote circulation
  • Gravity can aid in the fetal descent in upright, sitting, kneeling, and squatting positions
• Psychological response

  • Maternal psyche throughout the entire process is critical to bringing a positive outcome for her and her family
  • Factors promoting a positive birth experience: clear information about procedures, support, sense of mastery, trust in staff, positive reaction to pregnancy, personal control over breathing, preparation for childbirth
• Maternal physiologic responses to labor

  • Heart rate increases by 10 to 20 bpm
  • Cardiac output increases by 12% to 31% during the first stage of labor and by 50% during the second stage of labor
  • Blood pressure increases by up to 35 mm Hg during uterine contractions
  • Respiratory rate increases and more oxygen is consumed related to the increase in metabolism
• Fetal physiologic responses to labor

  • Periodic fetal heart rate accelerations and slight decelerations related to fetal movement, fundal pressure, and uterine contractions
  • Decrease in circulation and perfusion to the fetus secondary to uterine contractions (a healthy fetus is able to compensate for this drop)
  • Increase in arterial carbon dioxide pressure (PCO2)
  • Decrease in fetal breathing movements throughout labor
  • Decrease in fetal oxygen pressure with a decrease in the partial pressure of oxygen (PO2)
• Premonitory signs of labor

  • Backache: Constant low, dull backache caused by pelvic muscle relaxation
  • Weight loss: 0.5 to 1.5kg (1 to 3lbs) weight loss
  • Lightening: Fetal head descends into true pelvis about 14 days before labor
  • Contractions: Begin with irregular uterine contractions (Braxton Hicks) that eventually progress in strength and regularity
  • Increased vaginal discharge and bloody show: expulsion of the cervical mucus plug may occur
  • Energy burst: sometimes called "nesting" response
  • Gastrointestinal changes: less common; include nausea, vomiting, and indigestion
• True vs. False labor

  Not all contractions indicate labor
• Assessment on admission to L&D

  1. Obtain maternal history (and prenatal records)

  2. Physical exam

  3. FHR assessment

  4. Draw labs

  5. Observe emotions, support system, verbal interaction, language spoken

  6. Ask about the patient's concerns

  7. Educate on the birthing process

  8. Provide care with cultural consideration

  9. Consider racial disparities
• Vaginal examination

  • Part of the care for women in labor to assess the progress of labor
  • Exams are invasive and can be distressing and/or painful for many women
  • Educate the mother on the procedure; privacy and dignity should be provided
• Vaginal examination procedure

  1. Don sterile gloves, examiner inserts their index and middle fingers into the vaginal introitus

  2. The cervix is palpated to assess dilation, effacement, and position

  3. If cervix is open to any degree, the presenting fetal part, fetal position, station and presence of molding can be assessed

  4. Membranes are evaluated and described as intact, bulging, or ruptured
• Leopold maneuvers

  1. Method for determining the presentation, position, and lie of the fetus through the use of four specific steps

  2. Maneuver 1: What fetal part (head or buttocks) is located in the fundus?

  3. Maneuver 2: On which maternal side is the fetal back located?

  4. Maneuver 3: What is the presenting part?

  5. Maneuver 4: Is the feta; head in the flexed and engaged in the pelvis?
• Intermittent FHR Monitoring

  • Intermittent auscultation is a primary method of fetal surveillance
  • Does not detect variability and types of decelerations
  • Allows the woman to be mobile during first stage of labor
• Continuous Electronic Fetal Monitoring

  • External - Tocotransducer applied to fundus to monitor contractions, Ultrasound transducer records the baseline FHR, long-term variability, accelerations, and decelerations
  • Internal - Involves placement of a spiral electrode into the fetal presenting part, A pressure transducer is placed internally within the uterus to record uterine contractions
• Baseline fetal heart rate

  Average FHR that occurs during a 10-minute period, ranges from 110 to 160 bpm, excludes episodic rate changes of tachycardia or bradycardia
• Fetal bradycardia

  FHR less than 110 bpm and lasts 10 mins or longer, causes include fetal hypoxia, prolonged maternal hypoglycemia, fetal acidosis, analgesic drugs or epidural to the mother
• Fetal tachycardia


  FHR greater than 160 bpm and lasts 10 mins or longer, causes can represent early compensatory response to asphyxia, fetal hypoxia, maternal fever, maternal dehydration, amnionitis, drugs (cocaine, amphetamines)
• Baseline variability


  Irregular fluctuations in the baseline FHR, measured from the peak to trough in beats per minute, represents interplay of the sympathetic and parasympathetic nervous system, clinical indicator that is predictive of fetal acid-base balance and cerebral tissue perfusion