O&G Management of threatened preterm or preterm labour

Question 1

What is preterm labour?

Answer 1

Labour prior to 37 weeks gestational age

Question 2

How is labour clinically determined?

Answer 2

Regular uterine contractions and cervical dilatation of >3cm.

Question 3

How is threatened preterm labour defined?

Answer 3

Regular contractions in the absence or limited evidence of cervical dilatation

Question 4

What are the risk factors of preterm labour?

Answer 4

• Previous PTL
• Preterm PPROM
• Previous second trimester loss
• History of cervical surgery (cone biopsy, large loop excision of the transformation zone (LLETZ)
  with depth ≥ 10 mm)
• History of ≥ one surgical termination of pregnancy or evacuation of retained products of
  conception after miscarriage
• History of caesarean section at full cervical dilatation
• Congenital uterine and/or cervical anomalies
• Multiple pregnancy
• Polyhydramnios
• Recurrent bleeding in first trimester (≥ five days)
• Placental abruption/antepartum haemorrhage
• Smoking, alcohol or illicit drug use.

Question 5

How do you diagnose labour?

Answer 5

• History
• Exam
• Investigations

Question 6

What focused history do you want for a diagnosis of labour?

Answer 6

• Review history of sympoms of labour as similar symptoms can be present in:
• APH
• UTI
• Constipation

and review risk factors.

Confirm gestational age

Question 7

What examinations are important in the diagnosis of labour?

Answer 7

• Vital signs
• Abdo palpation to detect uterine activity, fetal size and presentation (lie)
• Sterile speculum exam (Avoid gel to allow fFN testing if indicated)
• Look for pooling of liquor (ROM), discharge, cervical dilatation and length.
• DVE
• CTG commenced.

Question 8

What investigations might you perform in the diagnosis of labour?

Answer 8

• MSU
• High vaginal swab for culture
• fFN if <34+6 weeks
• if fFN not available then consider transvaginal US of cervical length

Question 9

What is fFN and its utility?

Answer 9

Utilised for the prediction of preterm birth for women with symptoms of preterm labour.

Its trophoblast glue found in amniotic fluid. Only found between 22-36 weeks gestation in women with increased risk of preterm labour as indicated inflammatory / mechanical damage to membranes or placenta before birth.

Question 10

What are the potential interventions for threatened preterm labour?

Answer 10

• Admission
• Tocolysis
• antenatal corticosteroids
• +/- magnesium sulfate

Question 11

Whats the exclusion criteria for fetal FN?

Answer 11

• PPROM
• If delivery is warranted in next 7 days i.e placental abruption
• High order pregnancy
• > 35 weeks gestation

Question 12

What are the relative contraindications for fFN testing?

Answer 12

• Current vaginal bleeding
• Sex w/I 24hrs
• non-sterile speculum or DVE in last 24hrs
• TVUS in last 24hrs
• Increased odds of false positive. Negative will still be true negative.

Question 13

Describe the potential interventions for a preterm labour?

Answer 13

Following absence of PPROM if: (Follow those guidelines instead)

Active preterm labour
- Admit
- Corticosteroids
- Magnesium sulfate <30 weeks
- Tocolysis
- Group B strep prophylaxis
- NICU consult..
- Delayed cord clamping at birth.

Question 14

Whats the management if threatened preterm labour?

Answer 14

• Depends on fFN results
• Administer corticosteroids.
• Administer tocolysis if regular painful contractions (Nifidipine)

DO NOT GIVE
- MgS
- GBS prophylaxis

Appropriate follow up.