Preterm Labor, PROM and Postterm Pregnancy - Hibbs Flashcards Preview

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Flashcards in Preterm Labor, PROM and Postterm Pregnancy - Hibbs Deck (37):
1

What are the causes of preterm labor?

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

2

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

3

What can be used as a prediction of preterm labor?

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

4

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

5

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

6

What is not proven effective in preventing preterm labor?

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

7

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

8

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

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

9

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

1) RESPIRATORY DISTRESS
2) intraventricular hemorrhage
3) necrotizing enterocolitis

10

What is tocolysis?

The inhibition of uterine contractions

11

What is the diagnosis of preterm labor?

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

12

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

13

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

14

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

15

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

16

What is the definition of a postterm pregnancy?

pregnancy that persists beyond 42 weeks

17

What is the most common cause of postterm pregnancy?

inaccurate dating

18

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

19

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

20

What are the babies risks with a postterm pregnancy?

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

21

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

22

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

NO - except in diabetics

23

What is shoulder dystocia?

impaction of anterior shoulder against the pubis symphysis during delivery

24

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

25

What is oligohydraminos and what are its risks?

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

26

When does amniotic fluid reach its maximal volume?

34-36 weeks

27

How do you manage a postterm pregnancy?

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

28

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

29

After 16 weeks what produces most amniotic fluid?

Fetal urine

30

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

31

What is the definition of PROM?

rupture of the chorioamniotic membrane before onset of labor

32

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

33

What is the biggest and most concerning complication of PROM?

INFECTION
also cord prolapse and placental abruption

34

What is chorioamnionitis?

infection of fetal membranes or amniotic fluid

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

35

What are the signs and symptoms of chorioamnionitis?

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

36

What is the treatment for chorioamnionitis?

IV antibiotics and delivery

37

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