OB and labor complications QUIZ 4 Flashcards
What is the mean duration time of pregnancy?
40 weeks from the first day of last menstrual period
How long is “term”?
37 weeks completed to 42 weeks
How many births are pre-term and what percent of morbidity and mortality does it account for?
7-12% of deliveries in the U.S and accounts for over 80% of morbidity and mortality
What weight is considered low birth weight?
any infant under 2500 grams
What is considered VERY low birth weight?
any infant under 1500 grams
At ____ weeks gestation, ___ % of EFW are under ___ grams
At 29 wks GA, >90% of EFW are < 1500g.
Mortality approaches ___% for infants born <24 wks; survival exceeds 90% >30 wks, to >98% by 34 wks.
Mortality approaches 90% for infants born <24 wks; survival exceeds 90% >30 wks, to >98% by 34 wks.
How much does survival increase by each day between 25 and 26 weeks?
~5% each DAY!
What are the prematurity comorbidities?
Respiratory Distress Syndrome
- Exacerbated by intrapartum hypoxia, maternal stress - Almost all infants <27 wks GA, almost 0% by 36 wks GA.
Sepsis
Necrotizing Enterocolitis
Intracranial Hemorrhage (Uncontrolled delivery/trauma, neonatal HTN)
Ischemic Cerebral Damage
Immature Metabolism (prolonged drug effects)
Hypoglycemia
Hyperbilirubinemia
Is there any success treating PTL with antibiotics?
Some success preventing preterm labor with antibiotic treatment.
!! NO current recommendations for routine screening and treatment for asymptomatic infections.
How is PTL treated with breech presentations?
C-section is safer
Should you avoid maternal pushing against an incomplete cervix?
Yes!
What does tocolytic therapy do?
Attempts to stop or slow contractions to avoid PTL.
Is long-term tocolytic therapy proven to prolong gestation or reduce neonatal morbidity?
NO!
What is tocolytic therapy used for mainly?
Used for short-term (<48 hrs)
to permit corticosteroid treatment to aid fetal lung maturation
allow transfer to a facility with appropriate NICU facilities.
Tocolytic Therapy: ethanol
Inhibits release of antidiuretic hormone and oxytocin.
Possible direct effect on myometrium or interference with prostaglandins.
IV bolus and maintenance infusion over total of 12 hr.
Significant risk of intoxication, loss of consciousness and aspiration.
No longer used d/t side effects and superior drug availability.
Tocolytic Therapy: Methylxanthines (relatively weak bronchodilators)
Aminophylline
Phosphodiesterase – increase intracellular cAMP uterine muscle relaxation.
Narrow therapeutic margin and frequent toxic side effects limit clinical use.
Tocolytic Therapy: Calcium Channel Blockers
Nifedipine
Myometrium contractility related to free calcium concentration: dec.Ca2+ dec. contractility.
Maternal side effects
Hypotension, tachycardia, dizziness, palpitations
Facial flushing
Vasodilation, peripheral edema
Myocardial depression, conduction defects
Hepatic dysfunction
Postpartum hemorrhage
Fetal side effects
Decreased UBF fetal hypoxemia and fetal acidosis
Patient may be more prone to cardiac depressant effect of volatile agents.
May increase risk of postpartum hemorrhage due to uterine atony refractory to oxytocin and prostaglandin F-α2
Which tocolytic agent may make the patient more prone to the cardiac depressive effect of volatile anesthetics?
calcium channel blockers
Which tocolytic agent may increase risk of postpartum hemorrhage due to uterine atony refractory to oxytocin and prostaglandin F-α2?
calcium channel blockers
Tocolytic Therapy: Prostaglandin Synthetase Inhibitors
Indomethacin, Sulindac
Mechanism of action: dec. cyclooxygenase dec. prostaglandin
Maternal side effects:
Nausea
Heartburn
Transient dec. platelet aggregation bleeding
Primary pulmonary HTN
Fetal side effects:
Crosses placenta
Premature closure of ductusarteriosus
Persistent fetal circulation
Renal impairment, transient oliguria
TOCOLYTIC THERAPY: MAGNESIUM!
Magnesium:
May compete with calcium for uterine smooth muscle surface binding -> dec. contractility.
Prevents increased intracellular calcium.
Activates adenyl cyclase -> inc. cAMP.
Patient is more sensitive to both depolarizing and nondepolarizing muscle relaxants!!!
Are patients more sensitive to both depolarizing and nondepolarizing muscle relaxants with magnesium???
YES!!!!!!
Is MAC increased or decreased when using magnesium for tocolytic therapy?
MAC is decreased!
How is MAG eliminated for tocolytic therapy?
Renal elimination
More on Mag…
Normal treatment range is 4-7 mg/100 mL
Toxicity at greater values
8-10 = loss of deep tendon reflexes
10-15 = respiratory depression, cardiac conduction defects (wide QRS, inc P-R interval)
20+ = cardiac arrest
!!! Treatment with calcium gluconate or CaCl
Tocolytic therapy: Beta adrenergic agonists
Terbutaline, Ritodrine
Direct stimulation of β-adrenergic receptors in uterine smooth muscle -> inc. cAMP ->uterine relaxation.
Side effects:
Nausea, vomiting
Anxiety, restlessness
Hyperglycemia, hyperinsulinemia, hypokalemia, acidosis
Tachycardia, arrhythmias, dec. peripheral vascular resistance, dilutional anemia, dec. colloid oncotic pressure, pulmonary edema
Does an increase of cAMP induces vasodilatation?
YES!
Do beta agonists cause pulmonary edema? If so, how much?
1-5% of parturients receiving beta adrenergic tocolytic therapy
Risk factors for beta-agonist pulmonary edema?
Increased IVF administration
Multiple gestation
Tocolysis greater than 24 hrs
Concomitant magnesium therapy
Infection
Hypokalemia
Undiagnosed heart disease
Which twin has the higher risk of mortality?
the 2nd of the twins
Fetal mortality risk is increased – 5-6x in twins vs. singleton pregnancy
Incidence rising due to proliferation of assisted reproduction technology and ovulation inducing drugs
Risks of multiples
Cardiovascular
Increased cardiac output earlier in gestation
Hematologic
Increased incidence of anemia
Respiratory
Dec. TLC, dec. FRC, inc. closing capacity
Metabolic
Inc. oxygen consumption, inc. metabolic rate
Reproductive
Larger uterus – aortocaval compression, greater aspiration risk
Preterm labor complicates _____% of multiple gestations
Preterm labor complicates 40-50% of multiple gestations
Is vaginal delivery of twins usually ok?
OK unless twin A (first to deliver) is non-vertex presentation, i.e. breech
Is a breech delivery of the first twin ok?
no
What type of epidural is preferred for multiples due to rapid onset?
2-chloroprocaine 3% is preferred for rapid onset
What type of epidural is preferred for multiples due to rapid onset?
2-chloroprocaine 3% is preferred for rapid onset
What is used for uterine relaxation and may be required for internal manipulation?
Nitroglycerin 100 mcg initially, repeated to max of 500 mcg
Uterine rupture s/s
Sudden abdominal pain despite functioning epidural
Vaginal bleeding
Hypotension
Cessation of labor
Fetal distress – most reliable sign
Increased risk of postpartum hemorrhage
Dx – manual exploration, laparotomy
**What is the most common presentation?
is longitudinal – vertex or breech
**What is the greatest chance of uncomplicated spontaneous vaginal delivery?
with vertex presentation, flexed c-spine (chin to chest), occiput anterior (face down
**How are most breech pregnancies birthed by?
c-section
**What is an ABSOLUTE indication for a c-section?
Transverse lie!!
What are the risks of a breech baby?
placental abruption, hemorrhage, preterm labor
What type of anesthesia helps a breech baby?
Regional anesthesia
For delivery – epidural with backup plans for c-section.
What do you consider post-maturity?
Gestation beyond 42 wks, risks often evident at 40-41 wks
What do you consider post-maturity?
Gestation beyond 42 wks, risks often evident at 40-41 wks
Intrauterine Fetal Demise
Umbilical cord accidents
Prolapsed umbilical cord
Cord prolapsed through cervix, compressed, approx. 10 minutes window before fetal compromise.
Monoamniotic twins
Share single placenta and amniotic sack; risk cord entanglement.
Umbilical cord length
<30 cm risks compression, constriction, rupture.
>72 cm risks cord entanglement
Cord entanglement
Nuchal cords cause blood flow restriction
Torsion
