Components of Labor PDF

Learning Objectives: 1. Describe the components of labor. 2. Demonstrate skill in identifying abnormal patterns in fetal heart tone in relation to the uterine contraction; 3. Monitor frequency, interval and duration of uterine contractions; 4. Identify maternal danger signs of labor; 5. Di...

Learning Objectives: 1. Describe the components of labor. 2. Demonstrate skill in identifying abnormal patterns in fetal heart tone in relation to the uterine contraction; 3. Monitor frequency, interval and duration of uterine contractions; 4. Identify maternal danger signs of labor; 5. Distinguish early deceleration from late and from variable decelerations; and Learning Objectives: 6. Assess a family in labor and birth and identify the woman’s readiness, stage, and progression. 7. Formulate nursing diagnoses related to the physiologic and psychological aspects of labor and birth. 8. Develop expected outcomes to meet the needs of a family throughout the labor process. 9. Devise a nursing care plan using identified nursing diagnoses. 10. Implement nursing care for a family during labor such as teaching about the stages of labor. Learning Objectives: 11. Evaluate expected outcomes for achievement and effectiveness of care. 12. Integrate knowledge of labor and birth with the interplay of nursing process to promote quality maternal and child health nursing care. COMPONENTS OF LABOR ❑a successful labor depends on four integrated concepts: 1. The PASSAGE (the woman’s pelvis) 2. The PASSENGER (the fetus) 3. The POWERS (uterine factors) 4. The PSYCHE (the woman’s view) 1. PASSAGE ▪ Refers to the route a fetus must travel from the uterus through the cervix and vagina to the external perineum. ▪ Because the cervix and vagina are contained inside the pelvis, a fetus must pass through the bony pelvic ring. ▪ The pelvis must be of adequate size. ▪ 2 pelvic measurements are important to determine the adequacy of the pelvic size: a. the diagonal conjugate (the anterio- posterior diameter of the inlet) b. the transverse diameter of the outlet  The Pelvic Inlet At the pelvic inlet, the anteroposterior diameter is the narrowest diameter (12.5 cm)  The Pelvic Outlet At the outlet, the transverse diameter is the narrowest (11 cm)  If a disproportion between the fetus and pelvis occurs, the pelvis is the structure at fault. When an infant cannot be born vaginally, emphasize that it is the pelvis that is too small, not that the head is too big. 2. PASSENGER ▪ The passenger is the fetus ▪ The body part of the fetus that has the widest diameter is the HEAD, so this is the part least likely to be able to pass through the pelvic ring. ▪ Whether a fetal skull can pass or not depends on both its structure (bones, fontanelles, and suture lines) and its alignment with the pelvis. Structure of the Fetal Skull ▪ The cranium, the uppermost portion of the skull, comprises eight bones (important in childbirth): - 4 superior bones > the frontal (two fused bones) > two parietal > the occipital - the other four bones of the skull lie at the base of the cranium - they are of little significance in childbirth because they are never presenting parts > sphenoid > ethmoid > two temporal bones - The bones of the skull meet at suture lines - The suture lines are important in birth because, as membranous interspaces, they allow the cranial bones to move and overlap, molding or diminishing the size of the skull so that it can pass through the birth canal more readily. Fontanelles - membrane-covered spaces found at the junction of the main suture lines 1. Anterior fontanelle (bregma) * lies at the junction of the coronal and sagittal sutures * fusion of 2 frontal bones and 2 parietal bones making the anterior fontanelle diamond-shaped 2. Posterior fontanelle - lies at the junction of the lambdoidal and sagittal sutures - because the two parietal bones and the occipital bone are involved at this junction, the posterior fontanelle is triangular - smaller than the anterior fontanelle - fontanelle spaces compress during birth to aid in molding the fetal head - their presence can be assessed manually through the cervix after it has dilatated during labor - this helps establish the position of the fetal head and whether it is in a favorable position for birth - the space between the two fontanelles is referred to as the vertex - the area over the frontal bone is referred to as the sinciput; occipital bone is occiput Molding - is the change in the shape of the fetal skull produced by the force of uterine contractions pressing the vertex of the head against the not-yet-dilated cervix causing the bones of the fetal skull to overlap and cause the head to become narrower and longer. - only lasts a day or two Fetal Presentation and Position - two other factors play a part in whether a fetus is lined up in the best position to be born 1. Attitude - describes the degree of flexion a fetus assumes during labor or the relation of the fetal parts to each other a. Good attitude - is in complete flexion - the spinal column is bowed forward - the head is flexed forward so much that the chin touches the sternum - the arms are flexed and folded on the chest - the thighs are flexed onto the abdomen - and the calves are pressed against the posterior aspect of the thighs b. Moderate flexion - if the chin is not touching the chest but is in an alert or “military position” c. Partial extension - presents the “brow” of the head to the birth canal d. Poor flexion - the back is arched, the neck is extended, and a fetus is in complete extension presenting the occipitomental diameter of the head 2. Engagement - refers to the settling of the presenting part of a fetus far enough into the pelvis to be at the level of the ischial spines, a midpoint of the pelvis. - the degree of engagement is assessed by vaginal and cervical examination. - a presenting part that is not engaged is said to be “floating” - a presenting part that is descending but has not yet reached the ischial spines is called “dipping” Engagement 3. Station - refers to the relationship of the presenting part of a fetus to the level of the ischial spines. - when the presenting part is at the level of the ischial spines, it is at 0 station (synonymous with engagement) - if the presenting part is above the spines, the distance is measured and described as minus stations, which range from -1 to -4 cm. - if the presenting part is below the ischial spines, the distance is stated as plus stations (+1 to +4 cm) - at a +3 or +4 station, the presenting part is at the perineum and can be seen if the vulva is separated (crowning) 4. Fetal lie - is the relationship between the long (cephalocaudal) axis of the fetal body and the long (cephalocaudal) axis of a woman’s body - horizontal (transverse) or vertical (longitudinal) - approximately 99% of fetuses assume a longitudinal lie  Types of Fetal Presentation 1. Cephalic Presentation Most frequent type of presentation (95%) The fetal head is the body part that will first contact the cervix  Types of Cephalic Presentations TYPE LIE ATTITUDE DESCRIPTION VERTEX LONGITUDINAL GOOD The head is sharply flexed, making the parietal bones (FULL FLEXION) or the space between the fontanelles (the vertex) the presenting part. This is the most common presentation BROW LONGITUDINAL MODERATE Because the head is only moderately flexed, the brow or sinciput becomes the presenting part. FACE LONGITUDINAL POOR The fetus has extended the head to make the face the presenting part. From this position extreme edema and distortion of the face may occur. The presenting diameter is so wide that birth may be impossible. MENTUM LONGITUDINAL VERY POOR The fetus has completely hyperextended the head to present the chin. The widest diameter (occipitomental) is presenting. As a rule, the fetus cannot enter the pelvis in this presentation. 2. Breech Presentation means that either the buttocks or the feet are the first body parts that will contact the cervix. Breech presentations occur in approximately 3% of births and are affected by fetal attitude. Breech presentations can be difficult births, with the presenting point influencing the degree of difficulty It can be complete, frank, and footling. Types of Fetal Position- refers to the relationship of the presenting part to a specific quadrant of a woman’s pelvis.  Position is indicated by an abbreviation of three letters: 1. Middle letter denotes the fetal landmark 2. First letter defines whether the landmark is pointing to the mother’s right (R) or Left (L). 3. Last letter defines whether the landmark points anteriorly (A), posteriorly, (P), or transversely (T).  Mechanisms of Labor (DeFIRE ERE)  Descent  Flexion  Internal rotation  Extension  External Rotation  Expulsion 3. POWERS OF LABOR  Supplied by the fundus, are implemented by the uterine contractions, a process that causes cervical dilatation and then expulsion of the fetus from the uterus A  Phases of Contraction: a. Increment b. Acme c. Decrement  I D  Uterine Contraction A I D interval  Cervical Changes  Effacement- shortening and thinning of the cervical canal from a structure 1 or 2 cm in length to one in which no canal at all exists, except a circular orifice with almost paper-thin edges  Dilatation- enlargement of the cervical os from an orifice a few millimeters in size to an aperture large enough to permit the passage of a fetus (diameter about 10cm) 4. PSYCHE-  The 4th “P” or Psyche, refers to the psychological state that a woman brings into labor.  For many women, this is a feeling of apprehension or fright.  For almost everyone, it includes a sense of excitement or awe.