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Chapter 6 Process of Normal Labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 1.

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Presentation on theme: "Chapter 6 Process of Normal Labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 1."— Presentation transcript:

1 Chapter 6 Process of Normal Labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 1

2 Process of Labor and Birth Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 2

3 Objectives  Define key terms listed.  Explain labor, lightening, vaginal show, effacement, and cervical dilation.  Recognize spontaneous rupture of membranes.  Interpret the events that signal approaching labor. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 3

4 The Process of Labor  Labor is the process by which fetus, placenta, and amniotic membranes are expelled from the uterus  Fairly predictable sequence of events Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 4

5 Factors Contributing to Onset of Labor  Hormones  Stretching of uterus  Interaction among  Placenta  Fetal pituitary gland  Hypothalamus  Adrenal glands Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 5

6 Other Factors  Preparation  Prenatal classes help reduce fear of unknown  Position  Maternal preferences (sitting, squatting, etc) my influence progression of labor  Professional help  Nurse to help coach through labor process  Procedures  Can interrupt concentration/rapport during labor  People  Presence of supportive family can influence smooth progression of labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 6

7 Major Variables in the Birth Process Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 7

8 “Four Ps”  Pelvis—size and shape  Passenger—fetus size and position  Powers—effectiveness of contractions  Psyche—preparation, previous birth experiences Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 8

9 Pelvis  Pelvic curve must be negotiated by fetus during birth process  Angles are downward, forward, and upward Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 9

10 Passenger  Includes  Fetus  Placenta  Membranes  Amniotic fluid Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 10

11 Fetal Head  Can withstand pressure of uterine contractions and descent through birth canal  Stronger pressure is applied to head after rupture of membranes  Amniotic fluid no longer providing a “cushion” Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 11

12 Bony Skull of Fetal Head  Composed of several bones  Separated by strong connective tissue  Sutures  Fontanelles  Anterior and posterior Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 12

13 Audience Response System Question 1 Fetal heart rate is lowered during a contraction due to: A.Fetal position B.Maternal stress C.Decreased umbilical blood flow D.Decreased uterine blood flow Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 13

14 Powers, Positions and Psyche Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 14

15 Objectives  List the four main variables in the birth process.  Describe the ability of the uterine muscles to contract and relax.  Differentiate three distinctive characteristics of labor contractions.  Differentiate between false and true labor. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 15

16 Objectives (cont.)  Illustrate how frequency, duration, and intensity of contractions are monitored.  Describe fetal attitude, fetal lie, and fetal presentation. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 16

17 Fetopelvic Relationship  Fetal attitude  Relation of fetal parts to one another; flexion  Fetal lie  Relation of longitudinal axis of fetus to mother (should be parallel)  Fetal presentation  Body part lowest in mother’s pelvis (cephalic preferred)  Fetal position  R (right), L (left),  O (occiput), S (sacrum), M (mentum [face])  A (anterior), P (posterior) Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 17

18 Station  How far fetal presenting part has descended into mother’s pelvis  Imaginary line between ischial spines of maternal pelvis  Crowning: fetal head can be seen at vaginal opening Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 18

19 Powers: Uterine Contractions  Begin in top of uterus (fundus)  Spread throughout uterus in about 15 seconds  Retraction (or brachystasis): uterine muscles able to maintain shortening achieved during contractions  Results in progressive decrease in size of uterine cavity  Thickening of muscle tissue in upper portion of uterus  Forces fetus to descend Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 19

20 Uterine (Labor) Contractions  Each contraction should be followed by period of relaxation  Contractions cause decreased blood flow through  Uterine arteries  Intervillous spaces  Causes decline in fetal heart rate Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 20

21 Contractions and Maternal Position  Supine: contractions likely to be more frequent but not as strong  Side-lying: contractions likely less frequent but of greater intensity  Improves Progress of labor Oxygenation of the fetus Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 21

22 Contractions and the Cervix  Cause cervix to efface (thin) and dilate (open)  Before labor, cervix is 2-cm tubular structure  Contractions push fetus downward and pull cervix upward  Cervix becomes thinner and shorter  Effacement determined by vaginal exam  Described in percentage of original cervical length Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 22

23 Cervical Dilation  Determined by vaginal examination  Described in centimeters  Full dilation is 10 cm Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 23

24 Second Stage of Labor  Begins when cervix is 100% dilated  Woman uses abdominal muscles to increase intra-abdominal pressure, thereby increasing the force of the contraction  Bearing-down effort with abdominal muscles is consciously controlled  Helps to expel fetus Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 24

25 Uterine Contractions  Produce cervical effacement and dilation  Cause fetus to engage and rotate  Cause fetus to be delivered  Detach and expel the placenta Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 25

26 Characteristics of Uterine Contractions  Frequency  Beginning of one contraction to beginning of next  Duration  Beginning of contraction to end of same contraction  Intensity  Strength: mild, moderate, strong  Interval  Amount of time uterus relaxes between contractions Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 26

27 Phases of Contractions  Increment  The period of increasing strength  Peak, or acme  The period of greatest strength  Decrement  The period of decreasing strength Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 27

28 Psyche  Part of labor process  Anxiety or fear decreases woman’s ability to cope  Maternal catecholamines (stress hormones) known to inhibit contractility and placental blood flow  Relaxation augments natural process of labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 28

29 Conservation of Energy  Should be stressed until it is needed in the expulsion state  Will help woman avoid exhaustion and the development of an electrolyte imbalance  Can occur with hyperventilation and profuse perspiration Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 29

30 Events Before the Onset of Labor  Lightening  Vaginal discharge (show)  Energy spurt  False labor  No cervical changes  Spontaneous rupture of membranes  Cervical changes Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 30

31 Lightening  Fetus begins to settle in maternal pelvis  Moves downward toward pelvic outlet  Physical changes in woman  Easier breathing  More frequent urination  Leg cramps  Edema of the lower extremities Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 31

32 Vaginal Discharge (Show)  Blood-tinged mucous plug dislodges from cervical os  From rupture of superficial blood vessel  Pink-stained mucus Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 32

33 Energy Spurt  Some women have this a day or two before delivery  Referred to as “nesting”  Inform woman not to overexert herself  Will need energy for labor and delivery process Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 33

34 False Labor  Braxton-Hicks contractions  Painless  Can be felt when hand is placed on abdomen  Uncoordinated and irregular  May notice an increase in the last 2 to 3 weeks of gestation Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 34

35 Difference Between True and False Labor  Cervical changes, such as dilation, occur with true labor  Contractions become regular and increase in intensity Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 35

36 Rupture of Membranes  Spontaneous rupture of membranes (SROM)  Can be a trickle or rush of fluid  “My water broke”  At term, woman usually starts labor within 24 hours of SROM  If labor does not start after 24 hours, induction of labor may occur  Nitrazine paper test  To determine if fluid is amniotic or urine Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 36

37 Cervical Changes  Effacement: shortening and thinning of the cervix  Normally is 1 to 2 cm in length  When 100% effaced, cervix almost disappears  Dilation: enlargement of cervical os (opening) from 0 to 10 cm  At 4 cm woman’s active labor usually progresses to completion Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 37

38 Audience Response System Question 2 Contractions are described by frequency, duration, intensity, and: A.Interval B.Relaxation C.Increment D.Presentation Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 38

39 Stages of Labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 39

40 Objectives  List the six positions that the occiput of the fetal head may occupy in relation to the maternal pelvis.  Describe the term station as it relates to the maternal pelvis.  Distinguish six factors that influence the course of labor. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 40

41 Objectives (cont.)  Interpret what is accomplished in each of the four stages of labor.  Summarize the response of each body system to the labor process. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 41

42 Labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 42

43 Mechanisms of Labor  Cardinal movements are a series of actions that reflect changes in the posture of the fetus as it adapts to the birth canal  Most take place during second stage Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 43

44 Cardinal Movements of Labor  Mechanisms of labor (fetal posture changes) dictated by  Pelvic diameters  Maternal soft tissues  Size of fetus  Strength of contractions Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 44

45 Labor Proceeds  Along the path of least resistance  Adaptation of smallest achievable fetal dimensions to contour of maternal pelvis Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 45

46 Adaptive Movements  Of fetal head and shoulders  Includes  Descent and engagement  Flexion Internal rotation Extension External rotation  Expulsion  Placental expulsion Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 46

47 Floating  The fetal head moving toward the pelvic inlet  Head has not engaged Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 47

48 Engagement  Occurs when biparietal diameter of fetal head reaches level of ischial spine of mother’s pelvis  Presenting part is at 0 station or lower Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 48

49 Flexion of Fetal Head  Enables smallest fetal diameter to enter maternal birth canal Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 49

50 Internal Rotation  Fetal head rotates from transverse Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 50

51 Extension  Begins as fetal head reaches pelvic floor  Pivots under symphysis pubis  Advances upward  As extension progresses, occiput appears at vaginal opening (crowning)  Completed on delivery of fetal head Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 51

52 External Rotation  Called restitution  Occurs after head delivered  Head immediately rotates to transverse position  Shoulders align themselves to antero- posterior diameter of pelvic outlet Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 52

53 Expulsion  Anterior shoulder rotates forward, delivers, followed by posterior shoulder  Rest of body is then delivered  Birth of fetus ends second stage of labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 53

54 Placental Expulsion  Not a mechanism of labor  Usually takes anywhere from 5 to 30 minutes after delivery of fetus  Signs of placental separation  Lengthening of cord  Change in shape of uterus  Trickle or gush of blood from vagina Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 54

55 Placental Delivery  Duncan mechanism: placenta implanted low in uterus (dull, maternal side first)  Schultze mechanism: placenta implanted near fundus (fetal, shiny side first)  Delivery of placenta ends third stage of labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 55

56 The Four Stages of Labor Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 56

57 First Stage  Longest and most variable  Begins with onset of regular contractions  Contractions complete  Effacement of cervical canal (100%)  Dilation of cervix (10 cm)  This stage is complete when cervix is fully effaced and dilated Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 57

58 Phases of First Stage of Labor  Latent  Active  Transition Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 58

59 Latent Phase  Contractions become stabilized  Usually mild  Occur every 10 to 15 minutes  Last about 15 to 20 seconds  Fetal descent begins in earnest  Woman able to focus on any teaching being provided by health care team  Able to cope with what she is experiencing Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 59

60 Active Phase  Contractions stronger and longer  Contractions increase to 30 to 45 seconds in length and occur about every 5 minutes  Intensity is moderate to strong  Result is cervical dilation progressing from 4 to 7 cm  Fetus descends more  Assist woman with breathing techniques  Woman questions her ability to cope with what she is experiencing Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 60

61 Transition Phase  Dilation continues but is slower  Contractions more frequent, last longer (60 to 90 seconds), and are stronger  Woman may exhibit certain behaviors during this phase Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 61

62 Characteristics of Transition Phase  Restlessness  Difficulty following directions  Hyperventilation  Perspiration  Belching or hiccupping  Nausea or vomiting  Increased rectal pressure (“I need to have a bowel movement.”)  May be very irritable Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 62

63 Completion of Transition Phase  Woman may feel a splitting sensation by force of contractions and pressure of fetal head near cervix  As head descends, she may have urge to push because of pressure on sacral nerves from the head  Perineum begins to bulge and flatten  Head seen at vaginal opening Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 63

64 Second Stage of Labor  Begins when cervix is completely dilated  Ends with birth of fetus  Woman may feel urge to bear down  Uses abdominal muscles to assist with involuntary uterine contractions  Coach her not to hold breath more than 5 seconds at a time while pushing; may trigger a Valsalva’s maneuver Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 64

65 Valsalva’s Maneuver  Results from closed glottis, which leads to increased intrathoracic and cardiovascular pressure  Can diminish perfusion across placenta  Results in fetal hypoxia, and abnormalities can be seen in the fetal heart rate Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 65

66 Open-Glottis Breathing  Air is released through the mouth during pushing  Avoids buildup of intrathoracic pressure Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 66

67 Characteristics of Second Stage of Labor  Can last from a few minutes to 2 hours  Fetal head causes bulging of perineum  Crowning occurs when head is seen at external opening of vagina  Head appears to recede between contractions  Contractions forceful  Occur every 2 to 3 minutes and last 60 to 90 seconds  Increased bloody show usually occurs Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 67

68 Episiotomy  May be done to shorten second stage of labor  Used to prevent laceration of the perineum  Not done routinely Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 68

69 Delivery of Fetus  Nose and mouth are suctioned once head is delivered  Once body is delivered, umbilical cord is clamped in two places and cut  Nose and mouth may again be suctioned  Baby is handed off to pediatric nurse and pediatrician for examination  Mother is tended by obstetrician or nurse- midwife Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 69

70 Third Stage of Labor  Referred to as the placental separation stage  Begins with birth of fetus  Ends with expulsion of placenta  Can last up to 30 minutes Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 70

71 Fourth Stage of Labor  Stage of recovery  Begins with delivery of placenta  Lasts through 1 to 4 hours or until mother’s vital signs are stable  Blood loss during labor and delivery process can range from 250 to 500 mL  Leads to Drop in blood pressure Increase in pulse rate Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 71

72 Uterus in Fourth Stage of Labor  Must stay contracted to compress open blood vessels at placental site  Palpable as a firm, rounded mass at or below level of umbilicus  First hour after delivery is critical in observing mother for signs of excessive bleeding and assessing firmness of contracting uterus Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 72

73 Physiologic Changes in Labor  All of the woman’s body systems are affected by the labor process  Physiologic changes can be seen either directly or indirectly based on the clinical symptoms she exhibits  Nursing interventions are important and need to be provided in a timely manner Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 73

74 Audience Response System Question 3  What stage of labor is completed when the cervix is fully effaced and dilated? A.First B.Second C.Third D.Fourth Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 74

75 Review Key Points Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 75


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