Preterm Labour, PROM, and Prolonged Pregnancy

Question 1

How helpful is maternal risk scoring in predicting premature deliveries?

Answer 1

• Terrible

- Fail to identify up to 70% so of limited use

Question 2

What is the most important risk factor for pre-term labour?

Answer 2

• Prior preterm birth

Question 3

A woman comes in the preterm contractions concerning for preterm labour which two tests can help predict if she will deliver?

Answer 3

1) Fetal fibronectin
- glycoprotein that maintains integrity of chorionic-decidual interface

2) Cervical length (U/S)
- > 30mm has high negative predictor value

Question 4

What is the definition of true labour?

Answer 4

Regular, painful contractions of increasing intensity
Associated with:
- progressive dilatation and effacement of the cervix
- OR progression of station

Question 5

What is tocolysis?

Answer 5

Suppression of labour

Question 6

What is the goal of tocolysis?

Answer 6

• Delay delivery
• Typically does not inhibit pre-term labour completely but can buy time to transfer to appropriate center and administer steroids

Question 7

What are the contraindications to tocolysis?

Answer 7

1) Maternal Factors
- HTN
- DM
- Heart disease
- (pre)eclampsia
- chorioamnionitis

2) Fetal Factors
- erythroblastosis fetalis (Rh incompatability leading to fetal hemolysis)
- severe congenital abnormality
- fetal distress/demise
- IUGR

Question 8

What agents are used for tocolysis?

Answer 8

1) Calcium channel blocker (nifedapine)

2) Prostaglandin synthesis inhibitor (Indomethacin)

Question 9

What drug is used to enhance fetal pulmonary maturity? How is it given?

Answer 9

• Betamethasone valerate
• Given IM, looks like goal is to give 24mg total can by done in two ways
  a) 12mg q24h x 2 doses

b) 6mg q12h x 4 doses

Question 10

What is a maternal contraindication to corticosteroid use for fetal pulmonary maturity?

Answer 10

• Active TB

Question 11

What is cervical cerclage?

Answer 11

• Placement of cervical sutures at the level of the internal os

Question 12

When is the best time to perform cervical cerclage?

Answer 12

• 12 to 14 weeks

Question 13

When will cervical cerclage sutures be taken out?

Answer 13

• Elective removal at 37 weeks

- OR removed immediately at the onset of pre-mature labour to reduce the risk of cervical laceration and uterine rupture

Question 14

What is premature rupture of membranes?

Answer 14

• rupture of membranes prior to labor at any gestational age

Question 15

What is prolonged rupture of membranes?

Answer 15

• rupture of membranes for greater than 24 hours without the onset of labour

Question 16

What investigations can be done to investigate a potential PROM?

Answer 16

1) Speculum exam
- pooling of fluid in posterior fornix
- valsalva to exacerbate
- sterile (avoid introducing infection)

2) Nitrazine test
- pH test, nitrazine paper turns blue (basic)

3) Ferning
- High salt in amniotic fluid
- when fluid evaporates leaves fern pattern of salt

Question 17

How would you manage a PPROM at under 24 weeks?

Answer 17

• Consider termination

- Very poor outcome due to pulmonary hypoplasia

Question 18

How would you manage a PPROM at 26-34 weeks?

Answer 18

expectant management

- prematurity complications are significant

Question 19

How would you manage a PPROM at 34-36 weeks

Answer 19

• Grey zone

- approximate risk = between RDS and neonatal sepsis

Question 20

What is the definition of prolonged pregnancy?

Answer 20

• pregnancy greater than 42 weeks

Question 21

How would you counsel a term patient about when you may induce labour in a normal pregnancy?

Answer 21

• Offer IOL after 41 weeks if vaginal delivery is not contraindicated

Question 22

Why is prolonged pregnancy a bad thing?

Answer 22

• Higher perinatal mortality due to progressive placental insufficiency
• increased risk of meconium aspiration and infection
• postmaturity syndrome

Question 23

What is the definition of intrauterine fetal death?

Answer 23

Fetal death in utero after 20 weeks

Question 24

50% of intrauterine fetal deaths are idopathic. What are the secondary conditions that can lead to this outcome?

Answer 24

1- HTN
2- DM 
3- Erythroblastosis fetalis 
4- Congenital abnormality
5- Placental or umbilical cord issues 
6- Infection 
7- Antiphospholipid antibody syndrome

Question 25

What serum blood test would you expect to see with intrauterine fetal death?

Answer 25

• Increased AFP

- made in liver of fetus, escapes in certain conditions such as NT defect (or death)

Question 26

What would you expect to hear on history and physical exam of a patient with intrauterine fetal death

Answer 26

• decreased perception of movement
• SFH not increasing
• Absent fetal HR on doppler
• No FHR on US (needed for diagnosis)

Question 27

How do you manage a patient with intrauterine fetal death?

Answer 27

• Under 12 weeks D&C

- 13 + weeks, may require IOL

Question 28

What investigations are done following intrauterine fetal death? 3 categories

Answer 28

Think secondary causes:

1) Maternal: screen for DM, Infection, autoimmune
2) Fetal: karyotype, autopsy, amniotic fluid culture for infection
3) Placental: Pathology and culture