9.2 Premature Labour

Question 1

What is SROM?

Answer 1

Spontaneous rupture of membranes (amniotic sac ruptures, releasing amniotic fluid)

Question 2

What is PROM?

Answer 2

Prelabour rupture of membranes (before onset of labour)
or
Prolonged rupture of membranes (rupture more than 18hrs before delivery)

Question 3

What is P-PROM?

Answer 3

Preterm prelabour rupture of membranes (ruptured before labour and before 37 weeks, ie prem)

Question 4

At what gestation is a baby premature?

Answer 4

Before 37 weeks

Question 5

At what gestation is a baby viable?

Answer 5

viable at 23 weeks (10% chance; no resus if not showing signs of life)

higher survival at 24 weeks (full resus)

Question 6

What are the WHO classifications on prematurity?

Answer 6

under 28 weeks; extreme prem

28-32; very prem

32-37; moderate to late prem

Question 7

What prophylaxis options do you have to prevent preterm labour?

Answer 7

Vaginal progesterone

Cervical cerclage

Question 8

How does progesterone prophylactically prevent preterm labour?

Answer 8

Decreases activity of the myometrium and prevents cervix remodelling in preparation for labour.

Question 9

Who is offered prophylactic progesterone for preterm labour?

Answer 9

Between 16 and 24 weeks for women with a cervical length less than 25mm on vaginal US

Question 10

How does cervical cerclage prophylactically prevent preterm labour?

Answer 10

Puts a stitch into cervix to add support and keep it closed (under spinal or GA)
(removed once woman goes into labour)

Question 11

Who is offered prophylactic cervical cerclage for preterm labour?

Answer 11

Between 16 and 24 weeks for women with a cervical length less than 25mm on vaginal US
and had
a previous premature birth or cervical trauma (colposcopy or cone biopsy)

Question 12

What is a rescue cervical cerclage?

Answer 12

offered between 16 and 27+6 weeks when there is cevical dilatation without rupture of membranes (aims to prevent progression)

Question 13

What tests could be done to confirm PPROM?

Answer 13

• insulin-like growth factor-binding protein-1 (IGFBP-1) is in amniotic fluid and can be tested for in vaginal fluid if there is doubt about ROM
• placental alpha-microglobin-1 (PAMG-1) is alternative to IGFBP-1

Question 14

How do you manage PPROM?

Answer 14

• prophylactic Abx erythromycin 250mg 10days

- induction of labour is offered from 34 weeks… or 37 weeks now

Question 15

What is preterm labour with intact membranes?

Answer 15

regular painful contractions and cervical dilatation before 37 weeks and without ROM

Question 16

How do you diagnose preterm labour with intact membranes when less than 30 weeks gestation?

Answer 16

Diagnosis on clinical assessment alone
- speculum for dilatation
(regular painful contractions and cervical dilatation before 37 weeks and without ROM)

Question 17

How do you diagnose preterm labour with intact membranes when more than 30 weeks gestation?

Answer 17

Transvaginal ultrasound to assess cervical length:
>15mm mean preterm labour unlikely;
<15mm offer management for preterm labour.

(regular painful contractions and cervical dilatation before 37 weeks and without ROM)

Question 18

In preterm labour with intact membranes greater than 30 weeks you need transvaginal ultrasound to diagnose - what if you can’t get US / what is the alternative?

Answer 18

Fetal fibronectin greater than 50 ng/ml

this is the “glue” between the chorion and the uterus

Question 19

5 options for improving outcomes in preterm labour?

Answer 19

• tocolysis with nifedipine (CCB suppresses labour)
• corticosteroids (before 35 weeks reduce ARDs, NEC, ICH)
• magnesium sulphate IV (before 34 week to protect baby’s brain)
• delayed cord clamping or cord milking
• fetal monitoring (CTG or intermittent auscultation)

Question 20

What is tocolysis?

Answer 20

stopping uterine contractions

Question 21

Name two drugs for tocolysis?

Answer 21

1st line; nifedipine (CCB)

2nd line; atosiban (oxytocin receptor antagonist) when nifedipine contraindicated

Question 22

At what gestation can tocolysis be used?

Answer 22

between 24 and 33+6 weeks

Question 23

How long does tocolysis work for and what is the extra time used for?

Answer 23

short-term measure eg extra 48 hrs

• further fetal development
• administer steroids
• transfer to specialist unit (eg with NICU)

Question 24

At what gestation can you give corticosteroids?

Answer 24

between 24 and <35 weeks (34+6)

Question 25

What is an example regimen of maternal corticosteroids?

Answer 25

two doses of IM betamethasone, 24 hrs apart

reduce ARDs

Question 26

What medication can protect the fetal brain?

Answer 26

IV magnesium sulphate

reduces risk and severity of cerebral palsy

Question 27

At what timing can IV magnesium sulphate be given?

Answer 27

within 24 hrs of

preterm delivery less than 34 weeks

Question 28

How is IV magnesium sulphate administered?

Answer 28

bolus and then infusion for up to 24 hrs or until birth

Question 29

What is the risk of IV magnesium sulphate?

Answer 29

Magnesium toxicity in mum

- monitor four hourly

Question 30

What is monitored 4 hourly when on IV magnesium sulphate?

Answer 30

Signs of toxicity:

• reduced resp rate
• reduced BP
• absent reflexes (patella)