Pre term birth

Question 1

when is vaginal progesterone recommended?

Answer 1

asymptomatic women with cervix <25mm on TV scan in midtrimester
consider if previous spontaneous PTB

Question 2

what is RANZCOG position on cervical screening

Answer 2

acknowledges controversy
TA USS in midtrimester
<35mm repeat TV scanning

Question 3

What are the risk factors for PTB?

Answer 3

previous PTB
previous cervical surgery
fully C/S
ART
congenital and acquired uterine pathologies
multiple pregnancy
polyhydramnios
infection

Question 4

What length of cervix is 10thc and what is its RR of PTB?

Answer 4

30mm RR 3.8

Question 5

What length of cervix is 5th centile and what is RR for PTB?

Answer 5

27mm RR of 5.4

Question 6

What length of cervix is 2.5thcentile and what is the RR Of PTB?

Answer 6

22mm with RROf 6.3

Question 7

what is the evidence for use of daily progesterone in women at risk of PTB?

Answer 7

if cervix is <25mm the use of progesterone is associated with a reduction in PTB from 28-36 weeks the RR is 0.6

Question 8

What were the outcomes found on review of meta-analysis of 5 RCTs + 2016 OPTIMMUM trial for use of vaginal progesterone? Which risks were reduced

Answer 8

Reduced risk of PTB 0.62
Reduced RDS
Reduced composite of neonatal morbidity and mortality
Reduced low birth weight risk
Reduced NICU admissions

Question 9

What were the outcomes found on review of meta-analysis of 5 RCTs + 2016 OPTIMMUM trial for use of vaginal progesterone? No difference outcomes

Answer 9

No difference in maternal adverse events
no difference in adverse childhood neurodevelopment and health outcomes at 2 y/o
no difference in congenital anomalies

Question 10

what is the evidence for use of cervical cerclage for reducing risk of PTB?

Answer 10

reduces PTB in women with singleton pregnancy + short cervix (RR0.74)
reduces PTB in women with previous PTB + short cervix (RR0.61)
reduces PTB in women with previous midtrimester loss + short cervix (RR 0.57)
reduced PTB in women with progressive cervical shortening despite progesterone use

Question 11

How accurate is trans-abdominal scanning for picking up shortened cervix?

Answer 11

30mm cut off with full bladder has a sensitivity of only 38% for shortened cervix (<25mm on TVUS)
If the cut off is 36mm the sensitivity goes up to 96% (for detecting cervix <25mm by TVUS)
specificity is low and conversion to TVUS in 60% of cases

Question 12

Describe the use of MgSo4 in PTL

Answer 12

Magnesium sulphate
4g IV loading over 20ming then 1g iv/hr for atleast 4h prior to birth til 24h or until birth0 if still pregnant after 24h then stop infusion and repeat loading dose can be repeated when birth imminent
Proven to provide neuroprotection in large cochrane rv
Reduction in CP (RR 0.68, NNT 63) and gross motor dysfunction-Cochrane RV 2009

Question 13

describe the use of Steroids in PTL

Answer 13

Corticosteroids
Used 2x divded doses 11.4mg 12-24hr apart- ideally given 24h prior to delivery
Aims to improve fetal lung maturity
Proven to reduce the rate of RDS, NEC, NICU stay, IVH and NND by ~50%

Answer 14

Tocolytics
Nifedipine FA 10mg po q15min for up to 4 doses then MR 20-40mg q8h
This should be used to cease or halt progression of labour for enough time to allow full adminsitration of steroids
Should be continued for 24h after 2nd steroid dose
Should not be used if evidence of ROM,bleeding or fetal or maternal comprimise
Reduction in birth rates within 48h, 7d and before 34wks
Reduces RDS, IVH, NEC, jaundice

Question 15

Describe the use of antibiotics in PTL

Answer 15

IV antiboitocs
Used in those in preterm labour to reduce chance of Early onset Group B strep infection of the neonata
Benzyl penicillin 1.2 g loading then 600mg q4h IV- ideally administered at least 4h prior to birth
Should be started if you believe patient in preterm labour- can be stopped if labour is halteed
Reduction in the incidence of early onset GBS neonatal infection by >80%
1.5/1000—>0.25/1000