THE Incompetent Cervix Diagnosis & Management

1. Max Brinsmead PhD FRANZCOG December 2010 THE Incompetent CervixDiagnosis & Management

2. Classic Cervical Incompetence: • Is present when painless mid-trimester loss of apparently normal fetuses occurs recurrently • AND • The cervix accepts a 9 mm dilator without resistance in the non-pregnant interval • It can be successfully treated by prophylactic cervical cerclage • >95% term deliveries when patient acts as her own control • But there is probably a continuum of disorder with... • Pre term delivery • Findings of a short cervix • And that’s where it all gets confused

3. A little bit of history... • 1955 Shirodkar – an operation for recurrent miscarriage that restores the internal cervical sphincter • Performed at 14w • Bladder dissection & Mersilene tape • Removed at 37w • 1957 McDonald – a purse-string suture with nylon or any similar monofilament suture • An epidemic of “stitches for pregnancy loss” began • Not less than 1:100 patients • 1980 The era of Evidence-based medicine begins and questions were asked

4. More recent history... • Colposcopic evaluation of CIN and its limited treatment aims to avoid the risks of cervical incompetence associated with cone biopsy • Vaginal ultrasound and measures of cervical length • A relationship between short cervix and risk of pre term delivery emerges • Excellent visualisation of the internal os • Risks of cervical suture emerge • Infection with fetal & maternal sequelae • Cervical stenosis • Further cervical injury

5. Questions • How is cervical incompetence diagnosed? • Does a cervical suture do more good than harm? • What is the best form of suture? • Shirodkar or McDonald • Vaginal or abdominal • When should it be inserted? • Is there a place for cervical cerclage with advanced cervical dilatation? • Or should it be used prophylactically in high risk patients

6. But let ‘s digress & discuss aetiology... • Congenital • Associated with uterine abnormality • Example bicornuate uterus • With connective tissue disorder • Example Ehler’s Danlos • Idiopathic • Acquired • Inappropriate cervical dilation • For primary dysmenorrhoea • For termination of pregnancy • Cervical surgery • Cone biopsy • Cervical amputation

7. Surgical treatment of CIN • Limited treatments such as diathermy, Laser, LETZ & cryotherapy were designed to leave the upper cervix intact • Increased risk of pre term delivery after these procedures ascribed to concomitant factors esp. smoking • Current data suggests that all treatments for CIN increase the risk of pre term delivery • But whether this is due to “Cx incompetence” is unknown • And it is one reason why protocols for the management of HPV/CIN have been revised

8. Cochrane reviews of cervical cerclage • Meta analysis in 1989 by Grant of Cx cerclage for liberal indications concluded that... • They prevent ONE pre term delivery for every 20 inserted • The current review by Drakeley et al was posted in 2003 and updated 2010 • Reviewed RCT’s of cerclage vs no treatment • Compared methods of cerclage • Evaluated prophylactic and emergency cerclage • Particularly with respect to the optimal management of a short cervix diagnosed by ultrasound • Outcomes included possible adverse effects

9. 2010 Cochrane Review • 6 trials, 2175 women • No overall reduction in pregnancy loss or pre term delivery rate • Adverse effects include: • Mild pyrexia more common • More tocolysis used • More hospitalisations • Serious morbidity is uncommon • 2 trials of prophylactic cerclage for ultrasound-diagnosed short cervix • No reduction in the rate of delivery before 28 and 34 weeks

10. MRC/RCOG study of 1993 • Single largest trial, 1292 women • Multicentre and international • 80% were McDonald purse-string sutures • 74% used Mersilene tape • 13.8% of treated patients delivered before 32w • 18.5% of untreated controls (RR 0.75, CI 0.58 - 0.98) • But this means >80% patients did not deliver pre term • And one trial of strict bed rest had only 15% of patients delivering <32w

11. The most recent study: • Nicolaides et al 2001 • Recruiting 5000 women with cervix <15 mm diagnosed on ultrasound • This study has been stopped • Details awaited • Other data suggests that measures of Cx length are a normative continuum • And it is best used for its negative predictive value • Should be >18 mm before 18 weeks • And >25 mm before 28 weeks

12. Cochrane conclusions: • Cervical cerclage should NOT be offered to women at low or medium risk of mid-trimester pregnancy loss regardless of the length of the cervix as determined by ultrasound • The management of patients with pregnant patients with a short cervix requires further study

13. My recommendations: • Patients with a classic history of cervical incompetence should have a prophylactic cerclage after first trimester screening for aneuploidy • A McDonalds purse-string suture with nylon for most • But a few will require an abdominal suture • Other patients who are on the continuum of disorders that begins with classic cervical incompetence require individualised management

14. Individualised management may include: • Screening and treatment for bacterial vaginosis • Progesterone prophylaxis • Proven by RCT to reduce the risk of pre term delivery by 50% • Monitoring cervical length and dynamic evaluation of the internal cervical os • Emergency cervical cerclage before 24 weeks • Hospitalisation and bed rest after 26 weeks