12. Abnormalities and Complications of Labour and Delivery Flashcards
Define: Abnormal Progression of Labour (Dystocia) (3)
- expected patterns of descent of the presenting part and cervical dilatation fail to occur in the appropriate time frame; can occur in all stages of labour
- during active phase: >4 h of <0.5 cm/h
- during 2nd stage: >1 h with no descent during active pushing
Describe etiology: Abnormal Progression of Labour (Dystocia) (5)
- Power (leading cause): contractions (hypotonic, uncoordinated), inadequate maternal expulsive efforts
- Passenger: fetal position, attitude, size, anomalies (hydrocephalus)
- Passage: pelvic structure (CPD), maternal soft tissue factors (tumours, full bladder or rectum, vaginal septum)
- Psyche: hormones released in response to stress may contribute to dystocia; psychological and physiological stress should be evaluated as part of the management once dystocia has been diagnosed
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The 4 Ps of Dystocia
- Power
- Passenger
- Passage
- Psyche
Describe management: Abnormal Progression of Labour (Dystocia) (4)
- confirm diagnosis of labour (rule out false labour)
- search for factors of cephalopelvic disproportion CPD
- concern for dystocia if adequate contractions measured by intrauterine pressure catheter (IUPC) with no descent/dilatation for >2 h
- management: if CPD ruled out, IV oxytocin augmentation ± amniotomy
Name risks of dystocia (7)
- inadequate progression of labour is associated with an increased incidence of:
- maternal stress
- maternal infection
- postpartum hemorrhage (PPH)
- need for neonatal resuscitation
- fetal compromise (from uterine hyperstimulation)
- uterine rupture
- hypotension
Define: Shoulder Dystocia (2)
- fetal anterior shoulder impacted above pubic symphysis after fetal head has been delivered
- life threatening emergency
Describe etiology: Shoulder Dystocia (2)
- incidence 0.15-1.4% of deliveries
- occurs when breadth of shoulders is greater than biparietal diameter of the head
Name risk factors: Shoulder Dystocia (7)
- maternal:
- obesity
- DM
- multiparity
- previous shoulder dystocia
- fetal:
- prolonged gestation or macrosomia (especially if associated with GDM)
- labour
- prolonged 2nd stage
- instrumental midpelvic delivery
Describe presentation: Shoulder Dystocia (2)
- “turtle sign”: head delivered but retracts against inferior portion of pubic symphysis
- complications: fetal and maternal
Name fetal complications: Shoulder Dystocia (4)
- hypoxic ischemic encephalopathy (chest compression by vagina or cord compression by pelvis can lead to hypoxia)
- brachial plexus injury (Erb’s palsy: C5-C7; Klumpke’s palsy: C8-T1), 90% resolve within 6 mo
- fracture (clavicle, humerus, and cervical spine)
- death
Name maternal complications: Shoulder Dystocia (3)
- perineal injury
- postpartum hemorrhage PPH (uterine atony or lacerations)
- uterine rupture
Describe tx: Shoulder Dystocia (4)
- goal: to displace anterior shoulder from behind symphysis pubis; follow a stepwise approach of maneuvers until goal achieved
- other options
- cleidotomy (deliberate fracture of neonatal clavicle)
- Zavanelli maneuver: replacement of fetus into uterine cavity and emergent C/S
- symphysiotomy
Describe: Approach to the Management of Shoulder Dystocia (7)
ALARMER
- Apply suprapubic pressure and ask for help
- Legs in full flexion (McRobert’s maneuver)
- Anterior shoulder disimpaction (suprapubic pressure)
- Release posterior shoulder by rotating it anteriorly with hand in the vagina under adequate anesthesia
- Manual corkscrew i.e. rotate the fetus by the posterior shoulder until the anterior shoulder emerges from behind the maternal symphysis
- Episiotomy
- Rollover (on hands and knees)
*Note that suprapubic pressure and McRobert’s maneuver together will resolve 90% of cases
Describe prognosis: Shoulder Dystocia (1)
1% risk of long-term disability for infant
Define: Umbilical Cord Prolapse (1)
descent of the cord to a level adjacent to or below the presenting part, causing cord compression between presenting part and pelvis
Describe Etiology/Epidemiology: Umbilical Cord Prolapse (2)
- increased incidence with prematurity/PROM, fetal malpresentation (~50% of cases), low-lying placenta, polyhydramnios, multiple gestation, and cephalopelvic disproportion CPD
- incidence: 1/200-1/400 deliveries
Name: Umbilical Cord Accident Causes (8)
- Nuchal cord
- Type A (looped)
- Type B (hitched)
- Body loop
- Single artery
- True knot
- Torsion
- Velamentous
- Short cord <35 cm
- Long cord >80 cm
Describe presentation: Umbilical Cord Prolapse (2)
- visible or palpable cord
- FHR changes (variable decelerations, bradycardia, or both)
Describe tx: Umbilical Cord Prolapse (6)
- emergency C/S if not fully dilated and vaginal delivery not imminent
- O2 to mother, monitor fetal heart
- alleviate pressure of the presenting part on the cord by elevating fetal head with a pelvic exam (maintain this position until C/S)
- keep cord warm and moist by replacing it into the vagina ± applying warm saline soaks
- roll mother onto all fours or position mother in Trendelenburg or knee-to-chest position
- if fetal demise or too premature (<22 wk), allow labour and delivery
1/3 of protraction disorders develop into what? (1)
2º arrest of dilatation due to cephalopelvic disproportion (CPD)
Define: Uterine Rupture (3)
- associated with previous uterine scar (in 40% of cases), hyperstimulation with oxytocin, grand multiparity, and previous intrauterine manipulation
- generally occurs during labour, but can occur earlier with a classical incision
- 0.5-0.8% incidence, up to 12% with classical incision
Describe presentation: Uterine Rupture (7)
- prolonged fetal bradycardia – most common presentation
- acute onset of constant lower abdominal pain, may not have pain if receiving epidural analgesia
- hyper/hypotonic uterine contractions
- abnormal progress in labour
- vaginal bleeding
- intra-abdominal hemorrhage
- loss of station of the presenting fetal part
Name risk factors: Uterine Rupture (7)
- uterine scarring (i.e. previous uterine surgeries including C/S (especially classical incision), perforation with D&C, and myomectomy)
- excessive uterine stimulation (i.e. protracted labour, oxytocin, prostaglandins)
- uterine trauma (i.e. operative equipment, external cephalic version ECV)
- multiparity
- uterine abnormalities
- malpresentation
- placenta accreta
Describe tx: Uterine Rupture (3)
- rule out placental abruption
- maternal stabilization (may require hysterectomy), treat hypovolemia
- immediate delivery for fetal survival
Name complications: Uterine Rupture (5)
- maternal mortality 1-10%
- maternal hemorrhage, shock, disseminated intravascular coagulation (DIC)
- amniotic fluid embolus
- hysterectomy if uncontrollable hemorrhage
- fetal distress, associated with infant mortality as high as 15%
Name: Maternal Mortality Causes (8)
- Thromboembolism
- Cardiac event
- Suicide
- Sepsis
- Ectopic pregnancy
- HTN
- Amniotic fluid embolism
- Hemorrhage
* In Canada (2013), lifetime risk of maternal death is 1 in 5200
Define: Amniotic Fluid Embolus (1)
amniotic fluid debris in maternal circulation triggering an anaphylactoid immunologic response
Describe Etiology/Epidemiology: Amniotic Fluid Embolus (4)
- rare intrapartum or immediate postpartum complication
- 13-30% maternal mortality rate
- leading cause of maternal death in induced abortions and miscarriages
- 1/8000-1/80,000 births
Name risk factors: Amniotic Fluid Embolus (6)
- placental abruption
- rapid labour
- multiparity
- uterine rupture
- uterine manipulation
- induction medication and procedures
Name ddx: Amniotic Fluid Embolus (7)
- pulmonary embolus
- drug-induced anaphylaxis
- septic shock
- eclampsia
- HELLP syndrome
- abruption
- chronic coagulopathy
Describe presentation: Amniotic Fluid Embolus (3)
- sudden onset of respiratory distress, cardiovascular collapse (hypotension, hypoxia), and coagulopathy
- seizure in 10%
- acute respiratory distress syndrome (ARDS) and left ventricular dysfunction seen in survivors
Describe management: Amniotic Fluid Embolus (2)
- should be managed in the ICU by a multidisciplinary team
- supportive measures (high flow O2, ventilation support, fluid resuscitation, inotropic support, ± intubation) and coagulopathy correction
Define: Chorioamnionitis (1)
- infection of the chorion, amnion, and amniotic fluid
Desribe Etiology/Epidemiology: Chorioamnionitis (3)
- incidence 1-5% of term pregnancies and up to 25% in preterm deliveries
- ascending infection (microorganisms from vagina)
- predominant microorganisms include: GBS, Bacteroides and Prevotella species, E. coli, and anaerobic Streptococcus
Name risk factors: Chorioamnionitis (6)
- low parity
- prolonged ROM
- long labour
- multiple vaginal exams during labour
- internal monitoring
- bacterial vaginosis and other vaginal infections
Describe clinical features: Chorioamnionitis (4)
- Maternal fever ≥38º C
- Tachycardia (maternal or fetal)
- Tenderness (uterine)
- Foul and purulent cervical discharge
Describe investigations: Chorioamnionitis (2)
- CBC: leukocytosis
- amniotic fluid: Gram stain, glucose, or culture results consistent with infection
Describe tx: Chorioamnionitis (3)
- IV antibiotics
- ampicillin 2 g IV q6h + gentamicin 2 mg/kg load, then 1.5 mg/kg IV q8h
- anaerobic coverage (i.e. clindamycin 900 mg IV q8h)
- if at risk for endometritis, continue treatment post-partum especially if C/S delivery
- antipyretics
- proper labour progression (not an indication for immediate delivery or C/S)
Name complications: Chorioamnionitis (2)
- bacteremia of mother or fetus, wound infection if C/S, pelvic abscess, neonatal meningitis, neonatal sepsis, and neonatal death
- long-term infant complications: cerebral palsy and bronchopulmonary dysplasia
Describe etiology: Meconium (4)
- present early in labour in 10% of pregnancies, more common in postdate pregnancies
- in general, meconium may be present in up to 25% of all labours; usually NOT associated with poor outcome
- concern if fluid changes from clear to meconium-stained
- always abnormal if seen in preterm fetus
Describe: Particulate (thickened) meconium (4)
- is associated with lower APGARs
- an increased risk of meconium aspiration
- and perinatal death.
- Particulate meconium generally has a darker green or black colour, whereas thin meconium is usually yellow to light green
Describe etiology: Meconium (3)
- likely cord compression ± uterine hypertonia
- may indicate undiagnosed breech
- increasing meconium during labour may be a sign of fetal distress
Describe features: Meconium (2)
- may be watery or thicker (particulate)
- light yellow/green or dark green-black in colour
Describe tx: Meconium (2)
- call respiratory therapy, neonatology, or pediatrics to delivery room
- closely monitor FHR for signs of fetal distress
