Audit of the Preterm Birth Prevention Service in Worthing Hospital

     Neogi M1, Scandrett S1, Buddha L1, White C1

       1Worthing Hospital, University Hospitals Sussex NHS Foundation Trust    

Results

Interventions: 33% (59/177) required intervention:

• 28 - cervical cerclage (all McDonald sutures)

• 31 - progesterone-only till 32 weeks with cervical surveillance 16-24 weeks

Cerclage:

• Emergency - 2 placed in the case of premature cervical dilatation, no acute complication, both delivered >34/40 

• History-indicated - 1 true history-indicated (≥ 3 previous PTB);
  4 placed with history of previous cerclage

• Ultrasound-indicated (cervical length shortening) - 21 

Introduction

Preterm birth (PTB), defined as delivery at <37+0 weeks gestation, is a common complication of pregnancy, comprising around 8% of births in England and Wales1. It is the most important single determinant of adverse infant outcome with regards to survival and quality of life, with high rates of neonatal mortality and morbidity1. Our PTB clinic aims to identify those at risk of cervical insufficiency in time to intervene. 34 weeks gestation is noted to be a key milestone in terms of better prognosis for babies. 

Objective

The objective of our study is to evaluate the efficacy of our local PTB prevention service. 

Standards used:

• Saving Babies’ Lives Bundle Version 2 - Element 5 

• Green-top Guideline No. 75 Cervical Cerclage

Preterm deliveries:

On average, we saw a clear later gestation post cerclage than progesterone although this was not significant. 

Design

A retrospective audit was undertaken from 1st September 2021 to 31st August 2022. Patients were referred at booking with any risk factors as per Saving Babies’ Lives Bundle Version 2. The outcome measures were the overall rate of PTB, and the effectiveness of cervical cerclage and progesterone in preventing PTB.

21/177 (11.9) preterm deliveries in this high risk cohort

11 no preterm labour/PPROM - iatrogenic (e.g. due to PET)

4 PTL/PPROM following no intervention from PTM clinic

1. Cervical biopsy only → discharged from clinic without cervical length → 32+5 PTL

2. History of C-section at full dilatation → cervical length 34mm → discharged from clinic → 36+4 PTL

3. Didelphyius uterus → cervical length 31mm → discharged from clinic → 30+1 PPROM and PTL

4. History of LLETZ (subsequent term birth) → cervical length 34mm → discharged from clinic → 18+4 PPROM 

10 (5.6%) preterm labour (PTL)/PPROM

177 included

3/10 had cerclage then PTL/PPROM → birth at 34+5, 33+5, 28+5

3/10 had progesterone then PTL/PPROM → birth at 26+0, 20+4, 17+1

195 women referred from booking appointment with ≥1 risk factor

18 excluded (1st trimester loss, did not attend

 

Reason for referral: 88% had 1 risk factor; 12% had >1 risk factor for referral. Inappropriate referrals were primarily cervical biopsy only. Mean gestation at first appointment was 15+3 weeks (10+3 - 23+1 weeks with a positive skew).

LLETZ: Depth ≥ 1 cm is a risk factor for PTB and requires referral for assessment2. 100 were referred due to LLETZ. 40% of these had depth <1cm. 30% of these did require intervention for shortening cervix; all then resulted in term deliveries. 

Conclusions

• Majority of women seen <16/40, allowing early intervention

• We did see intervention required with LLETZ depth <1cm

• There has been a decrease in PTL rates in our unit, from 8% (2020-21) to 5.6% (2021-22), in line with the National Maternity Safety Ambition to reduce PTB rate from 8% to 6% by 2025

• The cost of running this service is minimal compared to the high cost of neonatal care for extreme preterm babies

By implementing this one-stop service, we have potentially reduced costs and helped prevent adverse infant outcomes related to prematurity. 

References

1. Saving Babies’ Lives Bundle Version 2 - Element 5

2. RCOG Green-top Guideline No. 75 Cervical Cerclage, June 2022 

Abbreviations: PPROM - premature prelabour rupture of membranes