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Intrapartum management. Labor. Labor is defined by contractions that occur with increasing frequency and intensity, causing dilatation of the cervix excludes incompetent cervix and contractions that occur without dilation (later stages of pregnancy). Stages of Labor . First Stage
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Labor • Labor is defined by contractions that occur with increasing frequency and intensity, causing dilatation of the cervix • excludes incompetent cervix and contractions that occur without dilation (later stages of pregnancy)
Stages of Labor • First Stage • Latent phase • Active Phase • Second Stage • Third Stage
First stage of labor • Latent phase • period between onset of labor and a point at which a change in the slope of cervical dilation is noted
First stage of labor • Active Phase • Cervical dilatation of 3 to 5 cm or more in the presence of uterine contractions
Seven Cardinal Movements • Engagement • descent of BPD to a level below the plane of the pelvic inlet • Descent • Flexion • Internal rotation • Extension • External rotation • Expulsion
Management • Intermittent monitoring • FHR every 30 minutes during first stage of labor • FHR at least every 15 minutes and preferably after each contraction during second stage • Continuous monitoring • external (doppler u/s, tocodynamometer) • internal (scalp electrode, intrauterine pressure transducer)
Monitoring • External tocodynamometry • change in shape of abdominal wall as a function of contractions • Intrauterine pressure transducer • fluid-filled catheter • Montevideo Unit (average intensity frequency/10 minutes) • <200 MVUs in 10 minutes --> oxytocin
Active management of labor • Amniotomy • Frequent cervical exams • Oxytocin administration for dilation rates of <1 cm/hour
Disorders of labor • Prolonged latent phase • >20 hours in nulliparas • >14 hours in multiparas • therapeutic rest with morphine • after rest, 85% progress to the active phase
Disorders of labor • Disorders of the active phase • primary dysfunctional labor • < 1.2 cm/hour in nulliparas • < 1.5 cm/hour in multiparous patients • secondary arrest of dilation • cessation of previously normal dilation for 2 hours • exam, amniotomy, intrauterine monitoring • arrest of the active phase after 2 hours --> c/s
Disorders of labor • Disorders of the second stage • Prolonged second stage should be considered • Nulliparous > 3 hours with regional anesthesia or > 2 no regional anesthesia • Multiparous > 2 hours with regional anesthesia or > 1 no regional anesthesia • protraction of descent • <1 cm/hour in nulliparas • <2 cm/hour in multiparas • arrest (failure) of descent • evaluate contractions, FWB, pelvis
Dystocia • Abnormalities of the powers uterine contractility and maternal expulsive efforts • Abnormalities involving the passenger –the fetus • Abnormalities of the passage – the pelvis
Operative delivery • Forceps • cephalic curve - concave to fit the head of the fetus • pelvic curve - fits the descending curve of the maternal pelvis • Blades solid or fenestrated • Shanks separated or overlapping
Operative delivery • Simpson • fenestrated blades, separated shanks • Tucker-McLane • solid blade, overlapping shanks
Forceps delivery Classified according to station of fetal head • Outlet forceps • scalp visible at introitus • fetal skull has reached pelvic floor • fetal head is at or on perineum • angle between AP line and sagittal suture does not exceed 45 degrees
Forceps delivery • Low forceps • application when leading point of the skull is at station 2+ or more • Mid-forceps • application when the head is engaged but presenting part is above +2 station
Indications for forceps delivery • Outlet forceps • shorten second stage (cardiac disease, maternal exhaustion), NRFHT • Low forceps • prolonged second stage, NRFHT, cardiac disease
Vacuum extraction • Suction induces a caput succedaneum (chignon) within the cup to which traditional force is applied during contractions • Same indications as forceps • May be possible with minimal anesthesia
Pre-requisites for operative delivery • Ruptured membranes • Full cervical dilation • Operator knowledge • Position and station of fetal head are known with certainty • Adequate anesthesia • Adequate pelvis • Engaged fetal head
Induction of Labor • Indications are not absolute should account for: • maternal and fetal condition • Gestational age • Cervical status
Induction of Labor • Abrupio placentae • Chorioamnionitis • Fetal demise • Gestational hypertension • Premature rupture of membranes • Maternal medical conditions (diabetes, renal disease, chronic pulmonary disease, chronic hypertension) • Fetal compromise • Preeclampsia, eclampsia
Induction • Assess adequacy of pelvis and cervical exam • Bishop score
Bishop prelabor scoring system A total of 9 or above indicates that induction should be successful.
Bishop score • Add 1 point to score for: • Preeclampsia • Each prior vaginal delivery • Subtract 1 point from score for: • Postdates pregnancy • Nulliparity • Premature or prolonged rupture of membranes
General guidelines • Cervical ripening with prostaglandins • Bishop Score <5 • Membranes intact • No regular contractions • Labor induction with oxytocin • Bishop Score >= 5 • Rupture of membranes
Methods • Surgical • stripping of membranes • separate chorioamniotic membrane from wall of cervix and LUS • prostaglandin release from membranes and adjacent decidua • ?maternal oxytocin release from posterior pituitary • efficacy not proven
Methods • Surgical • Amniotomy • success in multiparous patients • high success rate • observation of fluid for blood or meconium, access for IUPC • risks • cord prolapse • adverse change in fetal position • prolonged ROM, chorioamnionitis
Methods • Medical • IV Oxytocin (Pitocin) • titrate for contractions every 2-3 minutes • dosage varies from 0.5 to 40 mU/min of oxytocin • Prostaglandins • misoprostol (PGE1, Cytotec) • dinoprostone (PGE2, Prepidil, Cervidil) • Cervidil vaginal insert 10 mg released 0.3 mg/hour
Complications • Hypercontractility • NRFHT, abruptio placentae, uterine rupture • Water intoxication • oxytocin is related to vasopressin (ADH) • hyponatremia, confusion, convulsions, coma, CHF, death • Uterine rupture • grandmultiparous, prior uterine surgery, fetal malpresentation, overdistended uterus
Delivery of placenta • Detachment of decidua • Retroplacental hematoma • Contraction of myometrium, expulsion of placenta • Minutes after delivery of delivery • Up to 30 minutes