- Tie everything together

 Birth Passage
 Baby
 Relationship Between the Passage and the
Baby
 Physiologic Forces of Labor
 Psychosocial Considerations

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Consists of bony pelvis and soft tissues
Bony Pelvis (inlet, pelvic cavity, outlet)
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False pelvis above linea terminalis
True pelvis below linea terminalis
Types of pelvis
 Gynecoid – female, most common
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Android – male, usually not adequate
Anthropoid – narrow from side to side, usually adequate
Platypelloid – narrow from front to back, usually not adequate.
Baby usually lays transverse with shoulder or buttock presentation, usually requires c-section delivery.

Shape
Gynecoid Android Arthropod Platypelloid
Inlet
Midpelvis
Outlet

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Composed of bony parts that can assist or hinder childbirth
Bones involved in birth not fused
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2 frontal bones
2 parietal bones occipital bones
Sutures – membranous spaces between cranial bones
 Molding- bone overlap

 Intersections of the cranial sutures
 Used in identifying position of fetal head and assessing newborn after birth
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Anterior Fontanelle, diamond shaped, closes by
18 months
Posterior Fontanelle, triangle shaped, closes by
2–3 months

 Mentum – fetal chin
 Sinciput – brow
 Bregma – anterior fontanelle
 Vertex – between anterior and posterior fontanelles
 Occiput – occipital bone

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Biparietal – major transverse diameter, average
9.25 cm
Anterior-Posterior – varies with how much head is flexed, most favorable when head is fully flexed
Fetal Attitude – position of fetus
Fetal Lie – position of fetus compared to mother
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Longitudinal
Transverse

 Cephalic (most common, 97%) a) b) c) d)
Vertex
– occiput is presenting part
(most common)
Military
– head is in neutral position, top of head is presenting part.
Brow
– head partially extended, brow is presenting part.
Hard on baby’s neck. Can cause head and neck injuries.
Face
– head hyperextended, face is presenting part.
Can cause shoulder and neck injuries in the baby.

 Breech (3-4%)
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Complete
– both knees are flexed
Frank
– buttocks presents to pelvis
Footling
– one or both feet present to pelvis
 Shoulder Presentation (0.3%)
 Transverse Lie (C-section will be preformed)

 External Versionmother lies on back and the physician will try to make the baby move just by pushing on the mother’s abdomen.
 Cesarean Section
 Assess FHR for cord compression or fetal distress.

 When largest diameter of presenting part reaches or passes through pelvic inlet
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Primigravida – 2 weeks before term
Multigravida – several weeks or at onset of labor

 Relationship of presenting part to an imaginary line drawn at the ischal spines
 Ischial spine is narrowest part that the fetus must pass
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Zero station at level of ischial spines
Negative numbers above ischial spines
Positive numbers below ischial spines

 Relationship of the landmark on the presenting part to the maternal pelvis
 Left (L) or Right (R)
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Vertex – Occiput (O)
Face – Mentum (M)
Breech – Sacrum (S)
Shoulder – Acromion process (A)
Anterior(A), Posterior (P), or Transverse (T)

 Primary - uterine contractions
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Increment
 building up of the contraction fig 17-10
Decrement
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The “letting up” of the contraction
Frequency
 The time from beginning to beginning of contraction
Intensity
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Strength of contraction at peak. (palpating of the uterine fundus during a contraction) mild, moderate, and strong
 Duration
 Beginning of a contraction to end of same contraction.

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 New role transitionFears of financial instability, anger, cultural influences, etc.
Self expectations
Coping mechanisms
Support systems
Preparation for childbirth
Cultural influences
Fear
Enhancing birth experience

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Causes
 Hormones
 Progesterone
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“Keeps everything quiet”; maintains pregnancy
 Decreases motility and contractility of uterus
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Estrogen (Uterine Muscle Contractions)
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Stimulates contractions
Maturation of secondary sex characteristics
Help connective tissues to loosen and soften (cervix)
Oxytocin
 Causes contraction
 Prostaglandins
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 Essential for ovulation (help egg be expelled from the ovary)
Fetal Cortisol
 Corticotropin Releasing Hormone
Uterine Distention
Myometrial Activityputs pressure on soft connective tissue
Intraabdominal

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Lightening-
Fetal descends
 Easy of breathing, eat easier, more freq urination, more leg cramps, incr venous stasis = BLE swelling
Braxton Hicks-
Begins 1 st Trimester, contractions that incr as preg progresses (False Labor)
Cervical changes-
Early rigid - later soften of cervix. aka “ripening” to allow dilation.
Bloody show-
Mucous plug expels  small amount of blood loss (sign that labor will begin w/in 24-48hrs)
Rupture of Membranes-
50% give birth w/in 5hrs., 90% w/in 28hrs
Sudden burst of energycommon ~ 24-48hrs before labor. Many feel this is “nesting” on the mother.
Other vague signs-
N/V/D, heartburn, etc. before the onset of labor.

 True
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Regular contractions
Cervical changes
Contractions start in back and radiate around to abdomen
Pain not relieved with activity
 False
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Irregular contractions
No cervical changes
Contractions primarily in abdomen
Pain may be relieved with activity (walking)

 Stage One – Effacement and Dilatation
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Latent Phase“dormant” 0-3 cm; able to cope, talkative, high excitement
(4-6hrs, should not exceed 20hrs)
Active Phase4-7 cm; sense of helplessness, begins to fear loss of control
(Contractions lasting up to 60sec q 2-3min. Pain level worse)
Transition Phase“to go through” 8-10 cm; significant anxiety, fears being left alone, feels she may be torn apart
(60-90 sec contractions q 1-2 min. Talk them through, control breathing. Should last 3hrs)
 Increased rectal pressure when reaches 10 cm and need to bear down.
Pushing too soon can cause the cervix to swell delaying delivery.

 Begins with complete cervical dilation and ends w/ birth of the baby.
 Maternal urge to push
 May feel relieved that birth is imminent
 Apologetic
 Primigravidas- 2-3hrs
 Multigravidas- 5-30min

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pg 391
Descent-
1) Pressure from amitotic fluid, 2) direct pressure of uterine fundus, 3) contractions of abd muscles, 4) straightening of fetal body
Flexion-
Head is meeting resistance from the soft tissue of pelvis/cervix
 Fetal head must rotate to fit the dia of the pelvic cavity, which is widest in the ant/posterior diameter of the back
Internal Rotationfetal head must rotate to fit the diameter of the pelvic cavity which is widest in the anterior-pos anterior diameter.
Extensionresistance of the pelvic floor and the mechanical movement of the vulva opening anteriorly and forward with extension of the fetal head as it passes under the symphysis pubis.
Restitutionshoulder of the infant enter the pelvic inlet. Oblique and remain oblique.
Neck becomes twisted because of this position.
External Rotationas the shoulders rotate, the head turn to one side and the body will slide out quickly
Expulsionshoulder slips under the anterior-posterior pelvis and the baby is expelled.

pg391-2
Time from delivery of the baby to delivery of the placenta. Usually takes place within 30 minutes of infant delivery. If does not deliver in this time the cervix starts to close which can cause placental retention and infection.
Placental Separation
(uterus will then contract slowly)
Globular shaped uteruscontracts sharply causes placenta to loosen from side of uterus. Mother may have feeling of needing to bear down again.
Rise in fundus in abdomenphysician may push on the fundus to aid
Sudden gush of blood
Further protrusion of the umbilical cord
Placental Delivery
(Phys can press down on the fundus of the uterus to assist)
Maternal pushing can assist delivery
Retained if > 30 minutes
Shiny Schultze – inside out (grocery bag) Fig17-4
Dirty Duncan – outer edge to inside (nasty)

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Recovery 1-4 hours
 Decr BP, Incr Pulse, Incr HR
Hemodynamic changescan cause increase in pulse and drop in B/P because blood is redistributed.
Blood loss of 250 – 500 ml’s
Decreased blood pressure
Fundus between symphysis and umbilicus
Fatigued, thirsty and hungry
Bladder hypotonic
(make sure mother can urinate)

 Cardiovascular
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Stressed by Uterine Contractions
 Pain, anxiety, apprehension
Increased cardiac output
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300-500ml blood forced back into maternal circulation with each contraction
BP increases with uterine contractions
Position lowers cardiac output
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Supine
 cardiac output
Left lateral
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BP

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Respiratory
 Oxygen demand increases (due to uterine contractions)
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Hyperventilation may occur (control breathing)
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Monitor for tingling, numbness (finger, toes, lips) pH levels decr
 metabolic acidosis
Pushing increases lactate levels
Renal system
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 maternal renin, plasma renin, and angiotensiogen – important in uteroplacental blood flow
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Trauma to bladder
Blood and lymph drainage impaired from presenting part

 GI system
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Gastric motility and absorption
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Emptying time is
 causing
 risk of aspiration
Glucose levels
 causing
 insulin levels
 Immune system
 WBC 25 – 30,000 stress response

 Causes of pain
(from contraction of uterine muscle cells)
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Dilatation of cervix
Hypoxia of uterine muscle
Stretching of lower uterine segment
Pressure on adjacent structures
Distention of vagina
Uterine contractions
Delivery of placenta
Episiotomy repairmother usually does not feel episiotomy because of compression of the baby’s head on the perineal nerves.

 Preparation for birth – childbirth classes
 Respond by what is acceptable to culture
 Fatigue and sleep deprivation
 Less energy and inability to focus on task at hand
 Previous experience
 Anxiety

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Heartrate changes
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Early decelerations
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 intracranial pressure causes vagal response (normal)
Late decelerations (not to bad)
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 uteroplacental blood flow
Variable decelerations (worse)
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Cord compression
Assess and reassess!!! (Pg 424 will come up again later)
Acid-Base Status in Labor
 As uterine contractions increase, pH decreases slowly in response to hypoxia (also due to mother holding breath and bearing down)
Hemodynamic changes
 Fetal BP and placental reserves protective mechanism during anoxic periods. Uterus supports ventilation of the baby when mother is bearing down.