1. Max Brinsmead MB BS PhD May 2015

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

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