Care of Mother, Child, Adolescent Chapter 4 PDF

CARE OF MOTHER, CHILD, ADOLESCENT | NCM 107 CHAPTER 4: THE FOUR (4) P’S COMPONENTS OF LABOR STRUCTURE OF THE FETAL SKULL A successful labor depends on four integrated...

CARE OF MOTHER, CHILD, ADOLESCENT | NCM 107 CHAPTER 4: THE FOUR (4) P’S COMPONENTS OF LABOR STRUCTURE OF THE FETAL SKULL A successful labor depends on four integrated concepts: The cranium, the uppermost portion of the skull, comprises 1. The PASSAGE (the woman’s pelvis) eight bones (important in childbirth): 2. The PASSENGER (the fetus) o 4 superior bones 3. The POWERS (uterine factors) 1. The frontal (two fused bones) 4. The PSYCHE (the woman’s view) 2. Two parietal 1. PASSAGE 3. The occipital 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 o The other four bones of the skull lie at the base of the cranium o They are of little significance in childbirth because they are never presenting parts 1. Sphenoid 2. Ethmoid 3. Two temporal bones o The bones of the skull meet at suture lines At the outlet, the transverse diameter is the narrowest (11 cm) o The suture lines are important in birth because, as If a disproportion between the fetus and pelvis occurs, the membranous interspaces, they allow the cranial bones to pelvis is the structure at fault. move and overlap, molding or diminishing the size of the When an infant cannot be born vaginally, emphasize that it is skull so that it can pass through the birth canal more the pelvis that is too small, not that the head is too big. readily. 2. PASSENGER FONTANELLES The passenger is the fetus Membrane-covered spaces found at the junction of the main The body part of the fetus that has the widest diameter is the suture lines HEAD, so this is the part least likely to be able to pass through 1. ANTERIOR FONTANELLE (BREGMA) the pelvic ring. Lies at the junction of the coronal and sagittal sutures Whether a fetal skull can pass or not depends on both its Fusion of 2 frontal bones and 2 parietal bones making the structure (bones, fontanelles, and suture lines) and its anterior fontanelle diamond-shaped alignment with the pelvis. LAMAGON | BSN 2A  CARE OF MOTHER, CHILD, ADOLESCENT | NCM 107 CHAPTER 4: THE FOUR (4) P’S 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 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 Fontanelle spaces compress during birth to aid in molding the fetal head o Their presence can be assessed manually through the cervix after it has dilatated during labor o This helps establish the position of the fetal head and whether it is in a favorable position for birth o The space between the two fontanelles is referred to as the vertex o 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 LAMAGON | BSN 2A  CARE OF MOTHER, CHILD, ADOLESCENT | NCM 107 CHAPTER 4: THE FOUR (4) P’S 2. ENGAGEMENT TYPES OF CEPHALIC PRESENTATION 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” 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. 3. STATION Breech presentations can be difficult births, with the presenting Refers to the relationship of the presenting part of a fetus to point influencing the degree of difficulty the level of the ischial spines. It can be complete, frank, and footling. 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) 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). 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 LAMAGON | BSN 2A  CARE OF MOTHER, CHILD, ADOLESCENT | NCM 107 CHAPTER 4: THE FOUR (4) P’S DILATION 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) MECHANISMS OF LABOR 4. PSYCHE (DEFIRE ERE) The 4th “P” or Psyche, refers to the psychological state that a Descent woman brings into labor. Engagement For many women, this is a feeling of apprehension or fright. Flexion For almost everyone, it includes a sense of excitement or awe. Internal rotation Extension External Rotation 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 Phases of Contraction: A. Increment B. Acme C. Decrement UTERINE CONTRACTION 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 LAMAGON | BSN 2A