e.g regina

• Uterine Stretch Theory


  Any hollow body organ when stretched to capacity will necessarily contract and empty
• Oxytocin theory


  Labor, being considered a stressful event, stimulates the hypophysis to produce oxytocin from the posterior pituitary gland. Oxytocin causes contraction of the smooth muscles of the body, e.g., uterine muscles
• Progesterone Deprivation theory


  Progesterone, being the hormone designed to promote pregnancy, is believed to inhibit uterine motility. Thus, if its amount decreases, labor pains occur
• Prostaglandin theory


  Initiation of labor is said to result from the release of arachidonic acid produced by steroid action on lipid precursors. Arachidonic acid is said to increase prostaglandin synthesis which, in turn, causes uterine contractions
• Theory of Aging Placenta

  Because of the decrease in blood supply, the uterus contracts
• Essential Factors of Labor (5Ps)

  • Passages
  • Power
  • Passenger
  • Person
  • Position
• Passages


  • Serves as birth canal
  • Proves attachment to muscles, fascia and ligaments
  • Supports uterus during pregnancy
  • Provides protection to the organs found within the pelvic cavity
• Types of Pelvis


  • Gynecoid
  • Android
  • Platypelloid
  • Anthropoid
• Gynecoid pelvis


  Normal female type of pelvis, most ideal for childbirth, round shape, found in 50% of women
• Android pelvis


  Male pelvis, presents the most difficulty during childbirth, found in 20% of women
• Platypelloid pelvis


  Flat pelvis, rarest, occurs to 5% of women
• Anthropoid pelvis


  Apelike pelvis, deepest type of pelvis found in 25% of women
• Division of Pelvis


  • False Pelvis
  • True Pelvis
• False Pelvis


  Provides and directs
• True Pelvis


  The tunnel
• Inlet or Pelvic Brim


  Entrance to true pelvis
• Anteroposterior Diameters of Pelvis

  • Diagonal Conjugate
  • Obstetric Conjugate
  • True Conjugate
• Diagonal Conjugate


  Midpoint of sacral promontory to the lower margin of symphysis pubis (12.5 cm)
• Obstetric Conjugate


  Midpoint of sacral promontory to the midline of symphysis pubis (11 cm)
• True Conjugate


  Midpoint of sacral promontory to the upper margin of symphysis pubis (11.5 cm)
• Pelvic Canal


  Situated between inlet and outlet, designed to control the speed of descent of the fetal head
• Outlet


  Most important diameter of the outlet
• Powers (3I's)


  • Involuntary - not within the control of the parturient
  • Intermittent - alternating contraction and relaxation
  • Involves discomfort (compression, stretching and hypoxia)
• Phases of Uterine Contractions

  • Increment/Crescendo
  • Acme/Apex
  • Decrement/Decrescendo
• Intensity


  Strength of uterine contraction
• Intensity Levels


  • Mild - slightly tensed fundus
  • Moderate - firm fundus
  • Strong - rigid, board like fundus
• Frequency


  Rate of uterine contraction, measured from the beginning of a contraction to the beginning of the next contraction
• Duration


  Length of uterine contraction, measured from the beginning of a contraction to the end of the same contraction
• Interval


  Measured from the end of contraction to the beginning of the next contraction
• Blood Pressure

  • Should not be taken during a contraction as it tends to increase. Because no blood supply goes to the placenta during a contraction, all the blood is in the periphery that is why there is increased BP during uterine contractions.
  • BP readings should be taken at least every half hour during active labor
  • When a woman in labor complains of a headache, the first nursing action is to take BP. If it is normal, it is only stress headache; if the BP is increased, refer immediately to the doctor (it could be a sign of toxemia)
• Fetal Heart Rate (FHR)


  • Should not be mistaken for uterine soufflé (synchronizes with maternal pulse rate)
  • Normally 120 to 160 per minute
  • Should not be taken during a uterine contraction because it tends to decrease. Compression of the fetal head when the uterus contracts stimulate the vagal reflex which, in turn, causes bradycardia
  • Should be taken every hour during the latent phase of labor, every half hour during the active phase and every 15 minutes during the transition period
  • For any abnormality in FHR, the initial nursing action is to change the mother's position
  • Signs of fetal distress: Bradycardia (FHR less than 100/minute) or tachycardia (FHR more than 180/minute), Meconium - stained amniotic fluid in non - breech presentation, Fetal thrashing - hyperactivity of the fetus as it struggles for more oxygen
• Head


  • Biggest part of the fetal body
  • Always the presenting part
  • Turn to present smallest diameter
• Cranial Bones


  • 1 frontal bone
  • 2 parietal bone
  • 1 occipital bone
  • 2 temporal bone
  • 1 sphenoid bone
  • 1 ethmoid bone
• Suture Lines


  Allow skull bones to overlap (molding) and for further brain development
• Suture Lines


  • Sagittal Suture
  • Frontal Suture
  • Coronal Suture
  • Lambdoidal Suture
• Anterior Fontanel or Bregma


  Intersection of suture lines, diamond shaped, closes between 12 - 18 months, 3 x 4 cm
• Posterior Fontanel or Lambda

  Triangular shaped, closes between 2 - 3 months
• Diameters of the Fetal Head

  • Tranverse Diameters: Biparietal, Bitemporal, Bimastoid
  • Anteroposterior Diameters: Suboccipitobregmatic, Occipitofrontal, Occipitomental
• Biparietal Diameter


  Most important transverse diameter, greatest diameter presented to the pelvic inlet's AP and at the outlet's TD, average measurement is 9.5 cm
• Suboccipitobregmatic Diameter


  Smallest anteroposterior diameter, fully flexed (presenting part), measured from the inferior aspect of occiput to the anterior fontanel, average measurement is 9.5 cm