Intrapartum (Process of Labor & Delivery) PDF

Intrapartum (Process of Labor & Delivery) LABOR Refers to a series of events by which uterine contractions & abdominal pressure expel a fetus & placenta from the uterus. A.k.a. Childbirth/Parturition EUTOCIA – normal labor Puerperium – time from delivery of placenta to the 1st week...

Intrapartum (Process of Labor & Delivery) LABOR Refers to a series of events by which uterine contractions & abdominal pressure expel a fetus & placenta from the uterus. A.k.a. Childbirth/Parturition EUTOCIA – normal labor Puerperium – time from delivery of placenta to the 1st week postpartum  Theories of Labor Onset Uterine Stretch Theory Oxytocin Theory Progesterone Deprivation Theory Aging Placenta Theory Prostaglandin Theory Factors Affecting Labor and Birth Process (1)the passage (birth canal) (2) the passenger (fetus) (3)the relationship between the maternal pelvis and presenting part of the fetus (4)the powers of labor (5) position of the mother (6) psyche/psychological outlook 1. PASSAGE – the route a fetus must travel from the uterus through the cervix & vagina to the external perineum – must be of adequate size Two pelvic measurements important to determine the adequacy of the pelvic size: diagonal conjugate (the AP diameter of the inlet) transverse diameter of the outlet 1. PASSAGE Critical Factors: size of maternal pelvis (diameters of the pelvic inlet, midpelvis, and outlet) type of maternal pelvis (gynecoid, android, anthropoid, platypelloid) gynecoid android anthropoid platypelloid 1. PASSAGE Critical Factors: ability of the cervix to dilate and efface ability of the vaginal canal and the introitus to distend 2. PASSENGER – The fetus The movement of the fetus, through the birth canal is determined by several interacting factors: the fetal head fetal attitude fetal lie fetal presentation fetal position 2. PASSENGER A. FETAL HEAD Importance – From an obstetrical point of view, the most important part of the fetus because: 1. It is the largest part of the fetus 2. It is the most frequent presenting part 3. It is the least compressible of all parts ◆Bones – 7 bones: Frontal (2), parietal (2), temporal (2) & occipital (1) 2. PASSENGER A. FETAL HEAD Sutures – spaces between cranial bones Frontal – between 2 frontal bones Coronal – between frontal & parietal bones Sagittal – between 2 parietal bones (midline suture); MOST IMPORTANT suture – overrides in labor (molding) decreasing biparietal diameter by 0.5 to 1 cm. Lambdoidal – posterior suture; between parietal & occipital bones 2. PASSENGER A. FETAL HEAD Membrane-filled spaces called fontanels/fontanelles are located where the sutures intersect. – anterior fontanelle – posterior fontanelle – sphenoidal fontanelle – mastoid fontanelle 2. PASSENGER A. FETAL HEAD Fontanelles: Posterior fontanelle – triangular in shape, junction of parietal & occipital bones; closes at 2- 3 months (as early as 2 months & as late as 4 months) Anterior fontanelle (BREGMA)- diamond- shaped “soft spot” in front of the head, junction between frontal & parietal bones, (closes at 18 months) 2. PASSENGER A. FETAL HEAD 2. PASSENGER  The anterior and posterior fontanelles are clinically useful along with the sutures in identifying the position of fetal head in the pelvis and in assessing the status of the newborn after birth. Fontanelle spaces compress during birth to aid in molding of the fetal head. 2. PASSENGER A. FETAL HEAD Landmarks of the fetal skull: Mentum – fetal chin Sinciput – upper part of the skull, especially the anterior portion above and including the forehead Bregma – large diamond-shaped anterior fontanelle Vertex – area between the anterior and posterior fontanels Posterior fontanel Occiput – area of the fetal skull occupied by occipital bone 2. PASSENGER A. FETAL HEAD Head measurements ◆Transverse diameters: Biparietal : 9.25 cm: biggest transverse diameter Bitemporal : 8 cm. Bimastoid : 7 cm. ♦Antero-posterior diameters: Occipitomental : 13.5 cm. Occipitofrontal : 11-12 cm. Suboccipitobregmatic : 9.5 cm- smallest AP diameter 2. PASSENGER A. FETAL HEAD 2. PASSENGER B. FETAL ATTITUDE/ HABITUS - relation of the fetal body parts to each other ◆Flexion: head flexed on chest ◆Extension: head extended, occiput touches the back 2. PASSENGER B. FETAL ATTITUDE - Types: a. Complete flexion b. Moderate flexion c. Poor flexion d. Hyperextension 2. PASSENGER B. FETAL ATTITUDE 2. PASSENGER C. FETAL LIE - relation of the long axis (spinal column) of the fetus to the long axis (spinal column) of the mother ◆Longitudinal/vertical lie: cephalic or breech ◆Transverse/horizontal lie: shoulder ◆Oblique lie: unstable and always becomes longitudinal or transverse during labor 2. PASSENGER FETAL LIE & PRESENTATION Shoulder Presentation 2. PASSENGER OBLIQUE LIE 2. PASSENGER D. FETAL PRESENTATION - the body part of the fetus that enters the pelvic inlet and leads through the birth canal during labor. This is determined by a combination of fetal lie & the degree of fetal flexion (attitude). 2. PASSENGER ◆Cephalic – most frequent type of presentation – head presents (vertex, sinciput, brow, and face) – Types of Cephalic Presentation Vertex - occiput is the presenting part Sinciput - fetal head is partially flexed, with the anterior fontanel, or bregma, presenting Brow - fetal head is partially extended; the sinciput (forehead) is the presenting part Face - fetal head is hyperextended; the face is the presenting part 2. PASSENGER Cephalic: Types of Cephalic Presentation (A) vertex, (B) sinciput, (C) brow, and (D) face presentations 2. PASSENGER ◆Breech – Buttocks or feet present ☺Complete – knees & hips flexed, thighs on abdomen & calves on posterior thighs, buttocks & feet present ☺Frank – hips flexed & knees extended, buttocks present ☺Footling – hips & legs extended - one foot presents (single footling) - both feet present (double footling) 2. PASSENGER ◆Shoulder – Shoulder presents (most frequent one of the shoulders) – Fetal hand, elbow, back, abdomen, or side may present in the maternal pelvis 2. PASSENGER E. FETAL POSITION - the relationship of the presenting part to a specific quadrant of the woman’s pelvis - 4 quadrants of maternal pelvis (1)right anterior, (2) left anterior, (3) right posterior, & (4) left posterior - Four parts of fetus as landmarks: vertex presentation- occiput face presentation- chin (mentum) breech presentation- sacrum shoulder presentation- acromion process 2. PASSENGER E. FETAL POSITION indicated by an abbreviation of three letters first letter defines whether the landmark is pointing to the mother’s right (R) or (L) middle letter denotes the fetal landmark (O for occiput, M for mentum or chin, Sa for sacrum & A for acromion process). last letter defines whether the landmark points anteriorly (A), posteriorly (P) or transversely (T). 2. PASSENGER E. FETAL POSITION E x a m p le s o f f e t a l v e r t e x ( o c c ip u t ) p r e s e n t a tio n s i n r e la tio n t o f r o n t , b a c k , o r s id e o f m a t e r n a l p e lv i s M o s b y ite m s a n d d e riv e d ite m s © 2 0 0 6 , 2 0 0 2 b y M o s b y , In c. 7 of 27 2. PASSENGER Types of Fetal Position 3. Relationship between the maternal pelvis and presenting part of the fetus A. ENGAGEMENT the settling of the presenting part of a fetus far enough into the pelvis to be at the level of the ischial spines can be determined by vaginal examination and leopold’s maneuvers Floating; Dipping 3. Relationship between the maternal pelvis and presenting part of the fetus A. ENGAGEMENT 3. Relationship between the maternal pelvis and presenting part of the fetus A. ENGAGEMENT – Synclitism - occurs when the sagittal suture is midway between the symphysis pubis and the sacral promontory – Asynclitism - occurs when the sagittal suture is directed toward either the symphysis pubis or the sacral promontory and feels misaligned 3. Relationship between the maternal pelvis and presenting part of the fetus A. ENGAGEMENT 3. Relationship between the maternal pelvis and presenting part of the fetus B. STATION –relationship of presenting part to the level of the ischial spines (IS) – measure of the degree of descent of the presenting part of the fetus through the birth canal 3. Relationship between the maternal pelvis and presenting part of the fetus B. STATION (*** play video on station) 3. Relationship between the maternal pelvis and presenting part of the fetus B. STATION ◆Floating(-3) – presenting part above the inlet, in false pelvis ◆Dipping (-2) ◆Minus (-) presenting part above the IS ◆Fixed(-1) – presenting part below the inlet, in true pelvis, no longer moving but not yet engaged Station (-5) – presenting part @ pelvic inlet ◆ Engaged /Station O- presenting part at IS ◆ Plus (+) station – presenting part below IS ◆ (+4)-crowning (presenting part at perineum) ◆Station (+5) – presenting part at pelvic outlet 3. Relationship between the maternal pelvis and presenting part of the fetus 4. POWERS OF LABOR Involuntary and voluntary powers combine to expel the fetus, the fetal membranes and the placenta from the uterus – primary power/primary force – secondary power/secondary force 4. POWERS OF LABOR – primary power/primary force the involuntary uterine contractions signals the beginning of labor Rhythmic uterine contractions but intermittent. Between contractions there is a period of relaxation. 4. POWERS OF LABOR – primary power/primary force – physiological retraction ring 4. POWERS OF LABOR – primary power/primary force Each contraction has 3 phases: –increment –acme –decrement 4. POWERS OF LABOR – primary power/primary force Terms used to describe uterine contractions during labor: Note: Contractions occurring more often than every two minutes and persistent contraction duration longer than 90 seconds may reduce fetal oxy 4. POWERS OF LABOR – primary power/primary force Terms used to describe uterine contractions during labor: INTENSITY – Mild intensity – fundus indents easily & feels like a tip of your nose – Moderate intensity – fundus indents less easily (firm fundus that is difficult to indent) and feels like a chin – Strong intensity – fundus cannot be indented & feels like a forehead Note: Contractions occurring more often than every two minutes and persistent contraction duration longer than 90 seconds may reduce fetal oxygen supply and should be reported. 4. POWERS OF LABOR – primary power/primary force responsible for the effacement and dilation of the cervix and descent of the fetus. – Effacement - shortening and thinning of the cervix during the first stage of labor – Dilation/dilatation - enlargement or widening of the cervical opening and the cervical canal that occurs once labor has begun 4. POWERS OF LABOR – primary power/primary force 4. POWERS OF LABOR – primary power/primary force 4. POWERS OF LABOR – secondary power/secondary force use of abdominal muscles to push during the second stage of labor the voluntary bearing down efforts by the woman As soon as the presenting part reaches the pelvic floor, the contractions change in character and become expulsive. If the cervix is not fully dilated, bearing down can cause cervical edema (which retards dilatation), possible tearing and bruising of the cervix, and maternal exhaustion. 5. POSITION OF THE MOTHER – Frequent changes in position relieve fatigue, increase comfort, and improve circulation – a laboring woman should be encouraged to find positions that are most comfortable to her Upright position Lateral position Lithotomy position Semirecumbent sitting position Kneeling or squatting position 5. POSITION OF THE MOTHER 6. PSYCHE/PSYCHOLOGICAL OUTLOOK – woman’s psychological state or feelings that a woman brings into labor – a feeling of apprehension or fright and it includes a sense of excitement or awe Next: SIGNS OF LABOR