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
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
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?
2) maturation of lungs (and other complications)
What is the baby most at risk for after a preterm birth?
1) RESPIRATORY DISTRESS
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:
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)
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
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?
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?
2) shoulder dystocia
3) meconium aspiration syndrome
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?
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?
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
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
What is the treatment for chorioamnionitis?
IV antibiotics and delivery