Max Brinsmead MB BS Ph D May 2015

Max Brinsmead MB BS Ph. D May 2015 THE INCOMPETENT CERVIX DIAGNOSIS & MANAGEMENT

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

A little bit of history. . . 1955 Shirodkar – an operation for recurrent miscarriage that restores the internal cervical sphincter ○ Performed at 14 w ○ Bladder dissection & Mersilene tape ○ Removed at 37 w 1957 Mc. Donald – 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

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

Questions How is cervical incompetence diagnosed? Does a cervical suture do more good than harm? What is the best form of suture? ○ Shirodkar or Mc. Donald ○ 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

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

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

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

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

MRC/RCOG study of 1993 Single largest trial, 1292 women Multicentre and international 80% were Mc. Donald purse-string sutures 74% used Mersilene tape 13. 8% of treated patients delivered before 32 w 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 <32 w

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

Cochrane conclusions: Cervical cerclage should NOT be offered to women at low or medium risk of midtrimester 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

My recommendations: Patients with a classic history of cervical incompetence should have a prophylactic cerclage after first trimester screening for aneuploidy A Mc. Donalds 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

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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