Labor and Birth Process Overview

Types of Labor

• Prolonged labor lasts longer than 24 hours.
• Precipitate labor lasts less than 3 hours.
• Premature labor occurs between 28-37 weeks of gestation and results in a premature fetus.

Components of the Birth Process

• Power: The primary force is uterine contractions and the secondary force is maternal bearing down/pushing efforts.
• Passage: Consists of the maternal pelvis (bony pelvis) and soft tissues.
• Passenger: This includes fetal size, fetal lie, attitude, presentation, and position.
• Psyche: The psychological state of the mother, influenced by factors like culture and age.

Normal Labor Characteristics

• Spontaneous expulsion of the baby
• A single, mature fetus (38-42 weeks)
• Vertex presentation
• Vaginal delivery
• Labor duration between 3 and 18 hours
• No complications for the mother or fetus

Premonitory Signs of Labor

• Braxton Hicks Contractions: Irregular, mild uterine contractions that strengthen in the last trimester.
• Lightening: Fetal descent toward the pelvic inlet, occurring 2 to 3 weeks before labor. Increased pressure on the pelvis, causing frequent urination, and easier breathing.
• Increased Vaginal Mucous Secretions: This happens because of fetal pressure that congests the vaginal mucosa.
• Cervical Ripening and Bloody Show: The hormone Relaxin softens the cervix. As the fetal head descends, it presses on the cervix, initiating effacement and dilation. Bloody show is a mixture of blood and mucus, often preceding labor and the expulsion of the mucus plug.
• Energy Spurt: Also known as "nesting," a sudden increase in energy.

Fetal Position

• Anterior (A), Posterior (P), or Transverse (T): The fetal head is positioned in the anterior or posterior quadrant of the mother's pelvis.
• Four Quadrants: Right (R) and Left (L) anterior; Right and Left posterior
• Left Occiput Anterior (LOA): Fetal occiput faces the mother's left, anterior side.
• Right Occiput Anterior (ROA): Fetal occiput faces the mother's right, anterior side.
• Left Occiput Posterior (LOP): Baby's back is facing the mother's left, and the back of the baby's head is towards the mother's posterior.
• Right Occiput Posterior (ROP): Baby's back is facing the mother's right, and the back of the baby's head is towards the mother's posterior.

Fetal Heart Tone Positions

• The fetal heart tones can be heard in the location of the fetal back.

Passage: The Pelvis

• The linea terminalis (pelvic brim) divides the bony pelvis into the false pelvis (top) and the true pelvis (bottom), which consists of:
  • Inlet (upper pelvic opening)
  • Mid-pelvis (cavity)
  • Outlet (lower pelvic opening)

The True Pelvic Structure

• Inlet (Brim): Slightly transverse, oval shape.
  • Anteroposterior diameter of inlet (Obstetric diameter): 10.5 cm (middle of sacral promontory to the most prominent point of the symphysis pubis).
  • Oblique diameter: 12.5 cm.
  • Transverse diameter of inlet: 13.5 cm.
• The Pelvic Cavity (Midpelvis): The narrowest part of the pelvis where the fetus enters through the birth canal. Midpelvic diameters are measured at the level of the ischial spines, averaging 12 cm.
• Outlet: Three important diameters of the pelvic outlet:
  • Anterior posterior: 9.5-11cm
  • Transverse biischial: 11cm
  • Posterior sagittal: 7.5cm

Four Types of Pelvis

• Gynacoid
• Anthropoid
• Android
• Platypelloid

Fetal Station

• A measurement of fetal descent in relation to the ischial spines of the mother's pelvis.
• Measured in centimeters (cm).
• 0 Station: The presenting part is at the level of the ischial spines.
• The fetal descent is measured in centimeters (cm) above or below the ischial spine line.

The Pain of Labor and Childbirth

• Unique pain, different from other types of pain.
• Increased pain intensity is desired and viewed positively because it is associated with approaching birth.
• Pain occurs in a predictable pattern, starting without warning, but becoming predictable once established.

General Concepts of Pain

• Pain Threshold: The level of pain required for perception.
• Pain Tolerance: The ability to withstand pain once it is perceived.

Discomfort During Labor

• First stage: Visceral pain from cervical dilation and distention of the lower uterine segment (dull, aching, poorly localized).
• Transition and early second stage: Somatic pain from pelvic floor, vaginal, and perineal distention (sharp, severe, well-localized).
• Late second stage and actual birth: Pain is felt across different parts of the body as the baby descends and the perineum stretches.

Sources of Pain During Labor

• Physical Sources:
  • Tissue ischemia: Decreased blood flow to the uterus during contractions leading to hypoxia.
  • Cervical dilation.
  • Pressure and pulling of pelvic structures: Stretching of ligaments, uterine tubes, ovaries, bladder, and peritoneum, causing referred pain in the back and legs.
  • Distension of the vagina and perineum: Burning, tearing or splitting sensations.

Causes of Pain in Labor

• Stage One:
  • Stretching of the cervix during dilation and effacement.
  • Uterine anoxia.
  • Stretching of the uterine ligaments.
• Stage Two:
  • Distention of the vagina and perineum.
  • Compression of nerve ganglia in the cervix and lower uterus.
  • Pressure on the urethra, bladder, and rectum during fetal descent.
  • Traction on and stretching of the perineum.

Physiology of Pain in Labor

• First stage: Mostly visceral pain, due to dilation of the cervix and distention of the lower uterine segment. It is mediated by slow-conducting visceral C fibers entering the spinal cord at T10 to L1.
• Second stage: Mostly somatic pain, due to distention of the pelvic floor, vagina, and perineum. It is mediated by rapidly conducting A-delta fibers entering the spinal cord at S2 to S4.

Gate Control Theory

• Nerve impulses are controlled by a neural mechanism in the dorsal horn of the spinal cord that acts as a "gate."
• Pain is transmitted by small-diameter sensory nerve fibers.
• Stimulation of large-diameter fibers in the skin blocks the conduction of pain, effectively "closing the gate" and reducing the amount of pain felt.

Techniques of Pain Management

• Non-pharmacological: Based on the gate-control theory.
• Pharmacological: Regional anesthesia/analgesia.

Factors Affecting Mothers' Response to Pain in Labor

• Physiological: Physical condition, use of pharmacologic methods, age, labor experience, birth circumstances (planned/unplanned, wanted/unwanted, preterm/term).
• Psychosocial: Fear, anxiety, culture, preparation (knowledge and confidence from childbirth classes).

Factors Influencing Tolerance of Pain

• Intervention of caregivers: Intravenous lines, fetal monitoring equipment, vaginal examinations, amniotomy, and induced or augmented labor can all contribute to discomfort and pain.

Non-Pharmacologic Pain Interventions

• Relaxation techniques
• Birthing ball
• Patterned breathing
• Movement and position changes
• Music, subdued lighting
• Imagery
• Heat and cold application
• Massage (lower back), counterpressure

Advantages of Non-Pharmacologic Pain Interventions

• No delay or slowing of labor.
• No side effects or risk of allergy.
• Eliminate labor pain without extra techniques.
• A realistic option for women in advanced, rapid labor.
• Effective action on birth without requiring extra time.
• No risk for newborn respiratory effort from analgesia.

Limitations of Non-Pharmacologic Pain Interventions

• Women may not achieve the desired level of pain control using these methods alone.

Breathing Exercise

• Slow, deep breathing is effective.
• No rigid rules about breaths per minute, mouth/nose breathing, or sound production.
• Focus on conscious, controlled breathing.
• As contractions intensify, speeding up breathing and making it shallower may be helpful.

Breathing Techniques - First Stage

• Modified-paced breathing: Faster chest breathing maintains oxygen intake.
• Patterned-paced breathing: A set number of breaths, followed by an exhale with a slight blow.
• Breathing to prevent pushing: Blowing prevents glottis closure and the urge to push.

Breathing Techniques - Potential Risks

• Hyperventilation: May lead to "carpo pedal spasm" due to decreased calcium levels in tissues and blood.

Breathing Methods

• Basic Principles:*
• Comfortable position
• Chest breathing
• Focal point
• Verbal and non-verbal cues
• Cleansing breath
• Techniques:*
• Rhythmic chest breathing
• Shallow chest breathing
• Pant-blow breathing
• Exhalation pushing

Additional Notes on Breathing Methods

• Focusing on something (eyes closed or open) helps maintain breathing rhythm.
• Combining breathing techniques with movement, position changes, massage, and other relaxation strategies can be effective.

This quiz covers essential concepts of labor types, the birth process components, and the characteristics of normal labor. It also discusses premonitory signs of labor, providing a comprehensive understanding of the subject. Perfect for students studying obstetrics or maternal health.