Step Up To Obs/gyne: Chapter 22

Front 1

Preterm birth

Back 1

Delivery prior to 37 weeks

Front 2

Preterm labour

Back 2

preterm gestation with regular contractions and cervical changes (dilation and effacement)

Front 3

Causes of preterm labour

Back 3

Premature activation of maternal or fetal hypothalamic-pituitary-adrenal axis

a. maternal stress

b. fetal stress

Front 4

Risk factors for preterm labour?

Back 4

1. prior hx of preterm delivery

2. premature rupture of membranes (PROM)

3. infection

4. excessive uterine enlargement

5. uterine distortion

6. fetal

8. placental abnormalities

9. miscellanious

Front 5

T/F: usually no cause or risk factor for preterm labour is identified?

Back 5

True

Front 6

What percentage of babies in the US are born prematurely?

Back 6

12%

Front 7

Infectious causes of preterm labour?

Back 7

• amniotic fluid
• urinary
• bacterial vaginosis
• sexually transmitted infections
• periodontal disease

Front 8

Uterine enlargement risk factors associated with preterm labour?

Back 8

• multiple gestation
• polyhydramnios

Front 9

Uterine distortion risk factors associated with preterm labour?

Back 9

• leiomyomas
  
• septate uterus or other anomaly

Front 10

Fetal risk factors for preterm labour?

Back 10

• congenital anomaly
• growth restriction (fetal stress)

Front 11

Placental abnormalities/risk factors associated with preterm labour?

Back 11

• Placental abruption
• Placenta previa

Front 12

Miscellanious risk factors associated with preterm labour?

Back 12

• smoking or substance use
• african american
• age < 18 or > 40 years

Front 13

How to evaluate for preterm labour?

Back 13

• monitor contractions with tocometer
• evaluate for cervical change with speculum or digital exam
• look for signs of infection
• consider fetal fibronectin (fFN) at 24-34 weeks' gestation

Front 14

How to look for signs of infection when assessing for preterm labour?

Back 14

1. urinalysis
2. CBC
3. consider gonorrhoea and chlamydia cultures
4. evaluate for bacterial vaginosis
5. evaluate for chorioamnionitis

Front 15

How to evaluate for chorioamnionitis?

Back 15

Clinical diagnosis

2+ of:

• maternal tachycardia
• fetal tachycardia
• fever
• uterine tenderness

Amniocentesis may be performed

Front 16

T/F: when a cervical fFN is negative, the risk of delivering in the next 7-14 days is high?

Back 16

FALSE

Front 17

What is fFN?

Back 17

1. fFN: glycoprotein that functions to bind chorionic-decidual interface
   
2. Increased concentration of fFN in cervicogavinal secretions is found with preterm labour

Front 18

T/F: fFN must be collected during the speculum exam, prior to the digital exam?

Back 18

TRUE

Front 19

T/F: fFN has poor negative predictive value but good positive predictive value?

Back 19

FALSE

fFN has GOOD NPV but POOR PPV

Front 20

How to manage preterm labour?

Back 20

• assess fetal well being
• tocolysis
• administer corticosteroids
• Group B streptococcus (GBS) prophylaxis

Front 21

What is the main goal of tocolytic therapy?

Back 21

Prolong pregnancy for 48 hours to allow to administration of corticosteroids

Front 22

What percentage of patients with preterm contractions have spontaneous resolution of these contractions?

Back 22

50%

Front 23

How to assess fetal well being in preterm labour?

Back 23

• fetal heart rate monitoring
• ultrasound (fetal presentation and estimated fetal weight)

Front 24

T/F: tocolytics prolong pregnancy beyond 2-7 days?

Back 24

FALSE

Front 25

Contraindications to using tocolysis in preterm labour?

Back 25

• advanced labour
  
• mature fetus (rarely used after 34 weeks)
• intrauterine infection
• significant vaginal bleeding
• severe preeclampsia

Front 26

How to administer corticosteroids?

Back 26

2 X 12 mg doses of betamethasone or 4 X 6 mg doses of dexamethasone (48 hours to complete dosing)

Front 27

Why use corticosteroids?

Back 27

• Decrease incidence of respiratory distress syndrome
• Decrease incidence of intraventricular hemorrhage

Front 28

When to do GBS prophylaxis?

Back 28

GBS culture usually obtained in clinic at 36-37 weeks

Front 29

What to do if GBS status unknown?

Back 29

• Perform culture on admission
  
• Start antibiotics for prophylaxis if positive culture or unknown status

Front 30

What is cervical insufficiency?

Back 30

Recurrent second trimester cervical dilation and effacement leading to delivery in the absence of uterine contractions

Front 31

What is a cerclage?

Back 31

• Stitch around the cervix
• May be appropriate in setting of cervical insufficiency but not with preterm labour

Front 32

Give four examples of tocolytics?

Back 32

• Magnesium sulfate
• CCB (nifedipine)
• Beta Mimetic (e.g. terbutaline)
• Prostaglandin synthetase inhibitors (e.g. indomethacin)

Front 33

SEs of magnesium sulfate?

Back 33

• hypotonia
• respiratory depression
• cardiac arrest (at high levels)

Front 34

SEs of CCBs?

Back 34

• Hypotension
• headaches

Front 35

SEs of beta-mimetic?

Back 35

• tachycardia
• arrhythmias
• tremors
• hypokalemia
• hyperglycemia

Front 36

SEs of prostaglandin synthetase inhibitors?

Back 36

• GI distress
• premature closure of ductus arteriosus
• oligohydramnios