Preterm Labor, PROM and Postterm Pregnancy - Hibbs Flashcards Preview

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Flashcards in Preterm Labor, PROM and Postterm Pregnancy - Hibbs Deck (37):

What are the causes of preterm labor?

1) activation of maternal/fetal HPA axis
2) inflammation
3) decidual hemorrhage
4) pathological uterine distension


What are risk factors for preterm labor?

1) multiple gestations
2) prior history
3) cervical insufficiency
4) uterine distortion
5) placental abnormalities
6) maternal smoking (PROM)
7) bacterial vaginosis


What can be used as a prediction of preterm labor?

1) fFN - fetal fibronectin
a) glycoprotein produced by the amnion
2) cervical length


What are the limitations with using fetal fibronectin as a prediction for preterm labor?

1) poor positive predictive value (PPV)
2) great negative predictive value (NPV)
3) used bw 22-34 weeks
4) can't be done if the patient has had a manual exam, had sex in the last 24 hours etc


What about the cervical length is useful in assessing risk for preterm labor?

1) less than 2.5 cm is shortened (avg @ 24 weeks is 3.5 cm)
2) dynamic changes


What is not proven effective in preventing preterm labor?

1) prophylactic therapy with tocolytic drugs
2) bed rest
3) hydration


When do you used 17-alpha-hydroxyprogesterone caproate to prevent preterm labor?

1) start @ 16-20 weeks until 36 weeks
2) used in patients with documented preterm deliveries


Why are steroids given if preterm labor is threatened and which steroid is given?

1) Betamethasone
2) maturation of lungs (and other complications)


What is the baby most at risk for after a preterm birth?

2) intraventricular hemorrhage
3) necrotizing enterocolitis


What is tocolysis?

The inhibition of uterine contractions


What is the diagnosis of preterm labor?

1) uterine contraction
2) cervical change
3) before 37 weeks (up to 36 w 2 d)


How does Magnesium Sulfate cause tocolysis and what are side effects?

1) competes with calcium for entry into the cells
2) side effects:
a) flushing
b) headaches
c) respiratory depression at high levels


How do prostaglandin synthetase inhibitors (indomethacin) cause tocolysis and what are the side effects?

1) decreases PG production by blocking conversion of free AA to PG
2) side effects:
a) premature constriction of ductus
arteriosus (esp after 34 weeks)
b) oligohydramnios


How do CCB (Nifedipine) cause tocolysis and what are the side effects?

1) prevents entry of calcium into muscle
2) side effects
a) hypotension and headache
b) decrease in uteroplacental blood flow
c) DO NOT use with Mg Sulfate


How do beta-adrenergic agents (terbutaline) cause tocolysis and what are the side effects?

1) increases cAMP concentration in cells therefore decreasing free Ca2++
2) side effects
a) hypotension
b) tachycardia
c) anxiety
d) increased pulmonary edema


What is the definition of a postterm pregnancy?

pregnancy that persists beyond 42 weeks


What is the most common cause of postterm pregnancy?

inaccurate dating


How is a pregnancy dated?

1) gestational age always dated from first day of last menstrual period (LNMP)
2) assumes a 28 day cycle
3) first trimester ultrasound very helpful


How accurate is pregnancy dating with ultrasound?

1) Ultrasound at 6-12 weeks accurate within 3-5 days
2) ultrasound at 12-20 weeks accurate within 10 days


What are the babies risks with a postterm pregnancy?

1) macrosomia
2) shoulder dystocia
3) meconium aspiration syndrome
4) oligohydraminos


What is the definition of macrosomia and what is a common cause?

1) fetal weight greater than 4,000-4,5000 g
a) 8lbs 13 oz to 10lbs
2) diabetes and genetic factors


Does induction at 39 weeks or elective C section reduce to birth trauma from macrosomia?

NO - except in diabetics


What is shoulder dystocia?

impaction of anterior shoulder against the pubis symphysis during delivery


What are the consequences of shoulder dystocia?

1) Erb-Duchenne Palsy (waiters tip)
a) C5 and C6
b) paralysis of infraspinatus, deltoid and
flexor muscles of the forearm
2) Klumpke's Palsy
a) C8 and T1
b) hand paralysis


What is oligohydraminos and what are its risks?

1) AFI less than 5cm
2) risk of cord compression, uteroplacental insufficiency and meconium aspiration


When does amniotic fluid reach its maximal volume?

34-36 weeks


How do you manage a postterm pregnancy?

1) at 41 weeks
a) induce OR
b) antepartum fetal surveilance


How do you diagnos PROM?

1) History - gush of fluid or steady leaking
2) speculum exam - pooling of fluid
3) nitrazine test - uses pH to distinguish amniotic fluid from other fluids
4) Fern test - Na+ Cl- pattern


After 16 weeks what produces most amniotic fluid?

Fetal urine


What are the functions of amniotic fluid?

1) protects against infection, trauma and umbilical cord compression
2) allows for fetal movement and fetal breathing which allows skeletal development and lung maturation


What is the definition of PROM?

rupture of the chorioamniotic membrane before onset of labor


What are risks for PROM?

1) smoking doubles the risk
2) short cervix
3) prior preterm delivery
4) hydramnios
5) multiple gestations
6) bleeding early in pregnancy


What is the biggest and most concerning complication of PROM?

also cord prolapse and placental abruption


What is chorioamnionitis?

infection of fetal membranes or amniotic fluid

fetal sepsis is associated with risk of perventricular leukomalacia and cerebral palsy


What are the signs and symptoms of chorioamnionitis?

1) fever > 100.4
2) maternal or fetal tachycardia
3) uterine tenderness
4) contractions


What is the treatment for chorioamnionitis?

IV antibiotics and delivery


What is the management of PROM?

1) if gestational age > 34 weeks induce labor if it does not ensure within 24 hours and give GBS prophylaxis
2) 24-33 weeks - GBS prophylaxis, corticosteroids, antibiotics to prolong latency