The Labor Process

1. The Labor Process Labor is the series of events by which uterine contractions and abdominal pressure expel the fetus and placenta from the woman’s body. Regular contractions cause progressive dilatation of the cervix and sufficient muscular force to allow the baby to be pushed to the outside. A time of change, both ending and beginning for the woman, fetus and family. Woman uses all psychological and physical coping methods.

2. Nursing Process Assessment Outcome Identification and Planning Implementation Outcome Evaluation

3. Theories of Labor Onset Unknown Factors: • Uterine muscle stretching releases prostaglandin's. • Pressure on cervix stimulates release of oxytocin from posterior pituitary. • Oxytocin stimulation, works together with prostaglandin to initiate contractions. • Increasing estrogen in relation to progesterone stimulates contractions. • Placental age, triggers contractions at a set point.

4. Theories of Labor Onset • Rising fetal cortisol levels, reduce progesterone formation and increase prostaglandin formation. • Fetal membrane production of prostaglandin which stimulates contractions • Seasonal and time influences.

5. Signs of Labor Preliminary Signs of Labor: Before labor, the woman experiences subtle signs of labor. Teach how to recognize these. Lightening-descent of fetal presenting part into the pelvis. • Occurs 10 to 14 days before labor begins. • Shooting leg pains, increased vaginal discharge, urinary frequency.

6. Signs of Labor Increase in Level of Activity: • Feeling full of energy due to increase in epinephrine release initiated by decreased progesterone produced by placenta. Braxton Hicks Contractions: • Stronger 1 week to days before labor. • Support if not true contractions. Ripening of the Cervix: • Internal sign seen with pelvic exam. • Cervix is butter-soft and tips forward.

7. Signs of True Labor Uterine and cervical changes. Uterine Contractions: • Surest sign that labor has begun. • Effective, productive, involuntary uterine contractions. Show or Bloody Show: • Blood mixed with mucus when the mucus plug is expelled. • Pink tinged.

8. Signs of True Labor Rupture of the Membranes: • Either sudden gush or scanty, slow seeping of clear fluid from the vagina. • Amniotic fluid continues to be produced until delivery of the membranes. • Early rupture is good, fetal head settles snugly into the pelvis. • Risks: infection and cord prolapse. • Induce after 24 hours.

9. Components of Labor Four integrated concepts: • Passage • Passenger • Power of labor • Psyche of the woman is preserved. 1. Passage: • Route the fetus must travel from uterus through cervix and vagina to external perineum.

10. Components of Labor • Diagonal conjugate-anterior-posterior diameter of the inlet. • Transverse diameter of the outlet. • Pelvis structure at fault or fetal head is presented to the birth canal at a less than its narrowest diameter, not because the head is to large. Avoid negative thoughts about the baby.

11. Components of Labor 2. Passenger: Fetus is the passenger and must pass through the pelvic ring. Depends on fetal skull and alignment with the pelvis. Structure of the Fetal Skull: • Cranium-upper portion of skull • 4 superior bones-fontal, 2 parietal, and occipital are important in childbirth. • 4 at base of cranium-sphenoid bone, ethmoid bone and 2 temporal bones.

12. Components of Labor • Chin-mentum can be a presenting part. • Suture lines allow cranial bones to move and overlap, thus molding or diminishing the size of the skull so it can pass through the birth canal. • Fontanelles are membrane-covered spaces found at junction of the main suture lines. • Compress during birth to aid in molding of the fetal head. • Anterior fontanelle (bregma) lies a the junction of the coronal and sagittal sutures.

13. Components of Labor • Diamond shaped • Anteroposterior diameter-3 to 4 cm. • Transverse diameter-2 to 3 cm. • Posterior fontanelle-lies at junction of lambdoidal and sagittal sutures. • Triangular shape • 2 cm. across widest part. • Vertex-space between the two fontanelles

14. Components of Labor Diameters of the Fetal Skull: • Shape is wider anteroposterior than its transverse diameter. • Fetus must present transverse diameter to the smaller diameter of the maternal pelvis. • Biparital diameter-9.25 cm. • Outlet space-9.5 to 11.5 cm. • Engagement – setting of fetal head into the pelvis. • Depends on degree of flexion of fetal head.

15. Components of Labor • Inlet-12.4 to 13.5 cm. Molding: • Change in shape of the fetal skull produced by the force of uterine contractions pressing the vertex against the not yet dilated cervix. • Overlap and cause head to become narrower but longer. • Lasts 1 to 2 days not permanent. • No skull molding occurs when fetus is breech; buttocks are first.

16. Components of Labor Fetal Presentation and Position: • Attitude-degree of flexion the fetus assumes during labor or relation of the fetal parts to each other (figure 18.3 and 18.4). • Good attitude-complete flexion: • Spinal column bowed forward • Head flexed forward-chin touches the sternum • Arms flexed and folded on chest • Thighs flexed onto abdomen and calves pressed against posterior aspect of thighs • Ovoid shape

17. Components of Labor Moderate flexion-military position-chin not touching the chest. Partial extension-brow of head presents first. Engagement – settling of presenting part of fetus far enough into pelvis to be at level of ischial spines, at midpoint of pelvis. • Floating-a presenting part not engaged. • Dipping-a presenting part that is descending but not yet reached iliac spines • Assessed by vaginal and cervical exam.

18. Components of Labor Station: • Relationship of presenting part of fetus to level of ischial spines (figure 18.5). • Station 0 - presenting part at level of ischial spines (head is engaged). • Minus station – presenting part above the spines (-1cm to - 4cm) (floating). • Plus station – presenting part is below the spines (+1cm to +4cm) at +3 to +4 station presenting part is at perineum and can be seen if vulva is separated (crowning).

19. Components of Labor Fetal Lie: • Lie is relationship between long axis of fetal body and long axis of woman’s body. • 99% are longitudinal lie. Types of Fetal Presentation: Demotes the body part that will first contact the cervix or deliver first. Determined by fetal lie and degree of flexion (attitude). • Cephalic presentation-head is the fetal part that first contacts the cervix.

20. Components of Labor • Four types: • Vertex-best • Brow • Face • Mentum • Caput succedaneum-edematous area of fetal skull that contacted the cervix during labor. Breech Presentation: • Buttocks or feet are the first body part to contact the cervix. • 3% of births

21. Components of Labor • Affected by attitude • Types: • Complete • Frank • Footling Shoulder Presentation: • Transverse lie, fetus is lying horizontally in the pelvis so long axis is perpendicular to mother. • Presenting part-shoulders, iliac crest, hand or elbow.

22. Components of Labor • Fewer than 1% • Cesarean birth Types of Fetal Position: Relationship of presenting part to a specific quadrant of the woman’s pelvis. • Pelvis is divided into 4 quadrants according to the mother’s right and left. • 1. Right anterior • 2. Left anterior • 3. Right posterior • 4. Left posterior

23. Components of Labor • Abbreviations: (3 letters) • Middle letter denotes fetal landmark: O for occiput, M for mentum or chin, SA for sacrum, A for acromion process. • First letter defines whether the landmark is pointing to the mother’s right R or left L. • Last letter defines whether the landmark points anteriorly A, posteriorly P, or transversely T. • LOA-left occipitanterior- most common. • ROP-right occipitoposterior-second

24. Components of Labor • Six common positions • Position influences the process and efficiency of labor. • Fastest-ROA or LOA • Extended-ROP or LOP-more painful Importance of Determining Fetal Presentation and Presentation: • Presentations other than vertex puts the fetus at risk. • Implies proportional differences between fetus and pelvis.

25. Components of Labor Methods to determine position, presentation and lie: • 1. Abdominal inspection and palpation • 2. Vaginal exam • 3. Auscultation of fetal heart tones • 4. Sonography Mechanisms of Labor (Cardinal Movements) A number of different position changes to keep the smallest diameter of fetal head presenting to the smallest diameter of the birth canal.

26. Components of Labor Descent • Downward movement of biparietal diameter of fetal head to within pelvic inlet. Flexion • Fetal head bends forward onto chest. • Suboccipitobregmatic diameter. Internal Rotation • Head flexes as it touches pelvic floor, and occiput rotates until it is superior or just below the symphysis pubis, bringing head into best diameter for the outlet of pelvis.

27. Components of Labor • Brings shoulders into position to enter the inlet. Extension • As occiput is born, back of neck stops beneath the pubic arch and acts as a pivot for the rest of the head. • Head extends and foremost parts of head, face and chin are born. External Rotation • Immediately after head of infant is born

28. Components of Labor • Head rotates from anteroposterior position back to diagonal or transverse position of the early part of labor. • Anterior shoulder is born first, assisted by downward flexion of infant’s head. Expulsion • Once shoulders are born, the rest of the baby is born easily and smoothly. • End of the pelvic division of labor.

29. Powers of Labor Supplied by the fundus of the uterus. Implemented by uterine contractions A process that causes cervical dilatation Then expulsion After full dilatation of cervix power is abdominal muscles. Do not bear down with abdominal muscles until cervix is fully dilated. Could cause fetal and cervical damage.

30. Powers of Labor Uterine Contractions: Origin: • Begin at a pacemaker point located in the myometrium near one of the uterotubal junctions. • Each contraction begins at that point and then sweeps down over the uterus as a wave • After a short rest period another contraction is initiated. • In early labor, pacemaker is not synchronous

31. Powers of Labor • Pacemaker becomes more attuned to calcium concentration in myometrium and begins to function smoothly. Phases • 1. Increment-when intensity of contraction increases. • 2. Acme-when the contraction is at its strongest. • 3. Decrement-when intensity decreases. • Between contractions the uterus rests 10 min.early labor, 2 to 3 min. later.

32. Powers of Labor • Duration increasing from 20 to 30 seconds to a range of 60 to 90 seconds. Contour Changes • Upper-becomes thicker and active, preparing to exert strength to expel fetus. • Lower segment-becomes thin-walled, supple, and passive so it can be pushed out. • Physiologic retraction ring-ridge on inner uterine surface. • Contour changes to elongated.

33. Powers of Labor • Pathologic retraction ring (Bandl’s ring)-abdominal indentation that is a danger sign of impending rupture of lower uterine segment. Cervical Changes: Effacement-shortening and thinning of the cervical canal (normal 1 to 2 cm.) Dilatation-enlargement of cervical canal from a few millimeters to 10 cm. • Increases diameter of cervical canal lumen by pulling cervix up over presenting part.

34. Powers of Labor • Fluid filled membranes press against cervix. Psyche • Psychological state or feelings that women bring into labor with them. • Fright, apprehension,excitement, awe. • Debriefing time.

35. Stages of Labor Divided into 3 stages: • First stage of dilatation-beginning with true labor contractions and ending with cervix fully dilated. • Second stage-from time of full dilatation until the infant is born. • Third or placental stage-from the time the infant is born until after delivery of the placenta. • Fourth stage-first 1 to 4 hours after birth of the placenta.

36. First Stage of Labor Divided into 3 phases: 1. Latent 2. Active 3. Transition • Latent phase: • Preparatory phase-begins at the onset of regularly perceived uterine contractions and ends when rapid cervical dilation begins. • Contractions-mild and short 20 to 40 sec.

37. First Stage of Labor • Cervical effacement occurs • Cervix dilates from 0 to 3 cm • Phase lasts approx. 6 hours in nullipara and 4.5 hours in multipara. • Analgesics given too early in labor will prolong this phase. • Walking, preparation for birth, packing, care for siblings.

38. First Stage of Labor Active phase: • Cervical dilatation occurs more rapidly, from 4 cm to 7 cm. • Contractions are stronger, lasting from 40 to 60 sec., every 3 to 5 min. • Phase lasts from 3 hours in nullipara to 2 hours in multipara. • Show and rupture of membranes may occur. • True discomfort. • Dilatation 3.5 cm in nullipara per hour to 5 to 9 cm in multipara per hour.

39. First Stage of Labor • Analgesics has little effect on progress of labor. Transition Phase: • Dilatation 8 to 10 cm occur • Contractions at peak of intensity every 2 to 3 min. with duration of 60 to 90 sec. • If membranes not ruptured, will rupture at 10 cm. • If not occurred-show will be present and mucus plug is released.

40. First Stage of Labor • Full dilatation and complete cervical effacement occur. • Intense discomfort and nausea/vomiting, feeling of loss of control, anxiety, panic, irritability. • Her focus is inward on task of birthing. • Peak is identified by slight slowing in rate of dilatation when 9 cm is reached (deceleration on graph). • At 10 cm irresistible urge to push.

41. Second Stage of Labor • Full dilatation and cervical effacement to birth of infant. • Contractions change from crescendo-decrescendo pattern to uncontrollable urge to push. • N/V, she perspires, blood vessels in neck become distended. • Perineum begins to bulge and appear tense. • Anus appears everted, stool expelled, vaginal introitus opens, fetal head visible.

42. Second Stage of Labor • Crowning – at first slitlike opening then oval, then circular, from size of dime to that of a quarter, then half-dollar. • She can not stop pushing, all energy is directed toward birth. Third Stage: Placental stage begins with the birth of the infant and ends with delivery of the placenta Two separate phases: • Placental separation • Placental expulsion

43. Third Stage of Labor After birth the uterus can be palpated as a firm, round mass, inferior to level of umbilicus. Uterine contractions begin again and organ assumes a discoid shape until separated, approx. 5 min. Placental Separation: • Occurs automatically as uterus resumes contractions. • Folding and separation of the placenta occurs.

44. Third Stage of Labor • Active bleeding on maternal surface of placenta and this helps separate the placenta by pushing it away from its attachment site. Signs: • Lengthening of the umbilical cord • Sudden gush of vaginal blood • Change in the shape of the uterus Schultze-shiny and glistening side of placenta fetal surface. (80%) Duncan-looks raw, red irregular with ridges, maternal surface.

45. Third Stage of Labor • Normal blood loss-300 to 500 ml. Placental Expulsion: After separation, the placenta is delivered by natural bearing down effort or gentle pressure on fundus by physician. Never apply pressure to uterus in uncontracted state or uterus may evert and hemorrhage. Placenta can be removed manually. Saved for stem cell research.

46. Responses to Labor Maternal Response: Almost all body systems are affected. • Cardiovascular • Cardiac output • Blood pressure • Hemopoietic system • Respiratory • Temperature regulation • Fluid balance • Urinary

47. Responses to Labor • Musculoskeletal • Gastrointestinal • Neurologic and sensory Psychological Responses: • Fatigue • Fear • Cultural influences

48. Responses to Labor Fetal responses: • Neurologic system • Cardiovascular • Integumentary • Musculoskeletal • Respiratory

49. Danger Signs of Labor Fetal Danger Signs: • High or low fetal heart rate • Meconium • Hyperactivity • Fetal acidosis

50. Danger Signs of Labor Maternal Danger Signs: • Rising or falling blood pressure • Abnormal pulse • Inadequate or prolonged contractions • Pathologic retraction ring • Abnormal lower abdominal contour • Increasing apprehension