12. Abnormalities and Complications of Labour and Delivery Flashcards by Jimmy Chau

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

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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
The 4 Ps of Dystocia
- Power
- Passenger
- Passage
- Psyche

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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

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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

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Define: Shoulder Dystocia (2)

fetal anterior shoulder impacted above pubic symphysis after fetal head has been delivered
life threatening emergency

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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

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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

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Describe presentation: Shoulder Dystocia (2)

“turtle sign”: head delivered but retracts against inferior portion of pubic symphysis
complications: fetal and maternal

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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

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Name maternal complications: Shoulder Dystocia (3)

perineal injury
postpartum hemorrhage PPH (uterine atony or lacerations)
uterine rupture

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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

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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

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Describe prognosis: Shoulder Dystocia (1)

1% risk of long-term disability for infant

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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

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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

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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

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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