Cervical Cerclage

This is the second edition of this guideline; the first edition was published in 2011 under the same name. It supplements NICE guideline NG25 Preterm labour and birth. Cerclage remains one of the standard options for prophylactic intervention in the care of women at risk of preterm birth and second trimester fetal loss and is used by most obstetricians, despite difficulties in identifying the population of women who would most benefit. The procedure, a stitch inserted into the cervix, was first performed in 1902 in women with a history of second trimester loss or spontaneous preterm birth suggestive of cervical insufficiency, with the aim of preventing recurrent loss. Cervical insufficiency is an imprecise clinical diagnosis frequently applied to women with such a history, where it is assumed that the cervix is ‘weak’ and unable to remain closed during the pregnancy. Recent evidence suggests that, rather than being a dichotomous variable, cervical integrity is likely to be a continuum influenced by factors related not solely to the intrinsic structure of the cervix but also to processes driving premature effacement and dilatation. While cerclage may provide a degree of structural support to a ‘weak’ cervix, its role in maintaining the cervical length and the endocervical mucus plug as a mechanical barrier to ascending infection may be more important. There is lack of consensus on the optimal cerclage technique, timing of suture placement, the role of amniocentesis before emergency cerclage insertion and optimal care following insertion. Complications are not well documented and often difficult to separate from risks inherent to the underlying condition. The purpose of this guideline is to review the literature and provide evidence-based guidance on the use of cerclage in women at risk of preterm birth and second trimester loss. This guideline supplements NICE guideline [NG25] Preterm labour and birth.1 Within this document we use the terms woman and women’s health. However, it is important to acknowledge that it is not only people who identify as women for whom it is necessary to access women’s health and reproductive services in order to maintain their gynaecological health and reproductive wellbeing. Gynaecological and obstetric services and delivery of care must therefore be appropriate, inclusive and sensitive to the needs of those individuals whose gender identity does not align with the sex they were assigned at birth. This Royal College of Obstetricians and Gynaecologists (RCOG) guideline was developed in accordance with the standard methodology for producing RCOG Green-top Guidelines.2 The Cochrane Library (including the Cochrane Database of Systematic Reviews), DARE, EMBASE, TRIP, Medline and PubMed (electronic databases) were searched for relevant randomized control trials, systematic reviews and meta-analyses. The search was restricted to articles published between 2011 and April 2020. The databases were searched using the relevant MeSH terms, including all subheadings and this was combined with a keyword search. Search words included ‘cervical cerclage’, ‘cervical suture’, ‘cervical stitch’, ‘midtrimester miscarriage’, ‘McDonald cerclage’, ‘Shirodkar cerclage’, ‘infection and cerclage’, ‘tocolytics and cerclage’ and ‘inflammatory mediators and cerclage’; the search was limited to humans and the English language. The National Library for Health and National Guidelines Clearing House were also searched for relevant guidelines and reviews. The full search strategy is available to view online as supporting information (Appendices S1 and S2). Previous terminology (prophylactic, as a planned procedure, emergency, urgent, rescue) of cervical sutures/cerclage can be ambiguous. More appropriate nomenclature based on indication for cervical suture is recommended. The terms below are increasingly used in the scientific literature. History-indicated cerclage Insertion of a cerclage as a result of factors in a woman’s obstetric or gynaecological history, which increase the risk of spontaneous second trimester loss or preterm birth.3 A history-indicated suture is performed as a prophylactic measure in asymptomatic women and usually inserted as a planned procedure at 11–14 weeks of gestation. Preterm Birth Birth before to 37+0 weeks’ gestation. Ultrasound-indicated cerclage Insertion of a cerclage as a therapeutic measure in cases of cervical length shortening seen on transvaginal ultrasound.3 Ultrasound-indicated cerclage is performed on asymptomatic women who do not have exposed fetal membranes in the vagina. Sonographic assessment of the cervix is usually performed between 14 and 24 weeks of gestation by transvaginal scan and with an empty maternal bladder. Emergency cerclage (also known as physical exam-indicated or emergency cerclage) Insertion of cerclage as a salvage measure in the case of premature cervical dilatation with exposed fetal membranes in the vagina.3 This may be discovered by ultrasound examination of the cervix or as a result of a speculum/physical examination performed for symptoms such as vaginal discharge, bleeding or ‘sensation of pressure’. It can be considered up to 27+6 weeks gestation.1 Transvaginal cerclage (McDonald) A transvaginal purse-string suture placed at the cervical isthmus junction, without bladder mobilization.4 High transvaginal cerclage requiring bladder mobilization (including Shirodkar) A transvaginal purse-string suture placed following bladder mobilization, to allow insertion above the level of the cardinal ligaments.5 Transabdominal cerclage A suture performed via a laparotomy or laparoscopy, placing the suture at the cervicoisthmic junction.6 Occlusion cerclage Occlusion of the external os by placement of a continuous non-absorbable suture. The theory behind the potential benefit of occlusion cerclage is retention of the mucus plug.7 Routine surveillance of women at low risk is not currently recommended by the National Screening Committee. Ultrasound surveillance of cervical length is advocated in women at high and intermediate risk in Element 5 of the Saving Babies Lives Care Bundle,21 the timing of which is dependent on the women’s history. These women are recommended to be reviewed by a preterm prevention specialist by 12 weeks where possible, or with the dating scan whichever is sooner, and offered transvaginal cervix scanning as a secondary screening test every 2–4 weeks between 16 and 24 weeks. There is, however, uncertainty as to how to care for these women if a short cervix is identified in women who have had serial screening but do not have a history of a previous preterm birth; an ultrasound indicated cerclage may be considered. STOPPIT-2 is a randomised trial of the Arabin pessary to prevent preterm birth in twin pregnancies with a short cervix. Data collection is now complete and the results are currently being analysed.26 Carers should be aware of the potential psychological sequelae associated with fetal death and miscarriage, and women and their families supported by debriefing services and the offer of counselling. Families should also be signposted to the relevant patient support groups. There is no clear evidence that the gestation at which the cerclage is inserted affects the magnitude of prolongation of the pregnancy; however, consideration should be given to the fact that, in cases presenting before 20 weeks of gestation, insertion of a emergency cerclage is highly likely to result in a preterm birth before 28 weeks of gestation. Furthermore, emergency cerclage can rarely be justified beyond 24 weeks’ gestation due to the potential risk of iatrogenic membrane rupture and subsequent preterm birth. Prior to cerclage insertion, women should be given appropriate verbal and written information; patient information can be found on the RCOG website.50 The interval between presentation and suture insertion varies between studies. Any delay must balance the risk of inserting a suture in a cervix that is inevitably going to continue dilating against the increased risk of ascending infection. There are no studies evaluating the effect of sexual intercourse on the risk of second trimester loss or preterm birth in women with cervical cerclage. Although other tests are commercially available for the prediction of preterm birth, such as Partosure and Actim Partus no studies to date have evaluted their use following cervical cerclage insertion. Multiple studies have compared different agents (cerclage, progesterone and pessaries) for the prevention of preterm birth, however these often do not control for clinician preference and many of the studies are retrospective in nature. Conde-Agudelo et al.87 also compared the efficacy of vaginal progesterone and cerclage in preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth and short cervix undertaking a meta-analysis of RCTs comparing vaginal progesterone to placebo/no treatment or cerclage to no cerclage in women with a singleton gestation, previous spontaneous preterm birth and a sonographic cervical length less than 25 mm. Five trials comparing vaginal progesterone versus placebo and five comparing cerclage versus no cerclage were included. Both progesterone and cerclage were equally effective for preventing preterm birth and improving perinatal outcomes. However, cerclage and progesterone were not compared directly. A number of randomized controlled trials are planned comparing the efficacy of cerclage versus pessary versus progesterone.83, 88 There are no studies comparing elective removal of transvaginal cerclage with removal in labour. However, in the absence of preterm labour, elective removal at 36–37 weeks of gestation is advisable owing to the potential risk of cervical injury in labour and the minimal risk to a neonate born at this gestation. There are no studies regarding the use of anaesthesia in the removal of a cerclage inserted with bladder mobilization but, given that the technique involves burial of the suture, an anaesthetic is likely to be necessary for removal. Decisions regarding use of anaesthetic should be taken jointly with the woman. There are no published studies on long-term outcome comparing a policy of removing a transabdominal cerclage to it remaining in place. However, if further pregnancies are contemplated, it is reasonable to recommend leaving the cerclage in place. There have been anecdotal reports of suture ‘pulling through’ prior to labour, and a vaginal birth can occur safely if this is identified. The developers would like to acknowledge Miss Meekai To for their work as co-developer of the previous edition of this guideline. AHS has declared no conflicts of interest. LS has declared no conflicts of interest. Full disclosure of interests are available to view online as supporting information. All those involved in the development of the Green-top Guidelines, including the Guidelines Committee, Guidelines Committee co-chairs, guideline developers, peer reviewers and other reviewers, are unpaid volunteers and receive no direct funding for their work in producing the guideline. The exception to this are the RCOG staff involved who are salaried employees of the College and GC members who receive reimbursement for expenses for attending GC meetings. Please see more information on travel expense rules on the RCOG website. Appendix S1. Cervical cerclage literature search strategy. Appendix S2. Cervical cerclage search strategy top up. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. This guideline was produced on behalf of the Royal College of Obstetricians and Gynaecologists by: Professor Andrew H Shennan FRCOG, London; Dr Lisa Story MRCOG, London. and peer reviewed by: Miss A Gorry MRCOG, London; Dr G Kumar FRCOG, Wrexham; Mr D Fraser FRCOG, Norwich; Dr P Maouris FRCOG, Perth, Western Australia; Mr B Kumar FRCOG, Wrexham; Dr KC Dundas FRCOG, Edinburgh; Miss M To MRCOG, London; Professor JE Norman FRCOG, Bristol; RCOG Women’s Network; Imperial College Academic Health Science Centre. Committee lead reviewers were: Dr A Macleod FRCOG,1 Edinburgh, Dr B Magowan FRCOG, Melrose2 and Mr A McKelvey MRCOG, Norfolk.3 1until December 2020; 2until May 2021; 3from December 2021. The chair of the Guidelines Committee was: Dr MA Ledingham MRCOG, Glasgow; Dr B Magowan FRCOG, Melrose. All RCOG guidance developers are asked to declare any conflicts of interest. A statement summarising any conflicts of interest for this guideline is available from: https://www.rcog.org.uk/en/guidelines-research-services/guidelines/gtg75. The final version is the responsibility of the Guidelines Committee of the RCOG. The guideline will be considered for update 3 years after publication, with an intermediate assessment of the need to update 2 years after publication. The Royal College of Obstetricians and Gynaecologists produces guidelines as an educational aid to good clinical practice. They present recognised methods and techniques of clinical practice, based on published evidence, for consideration by obstetricians and gynaecologists and other relevant health professionals. The ultimate judgement regarding a particular clinical procedure or treatment plan must be made by the doctor or other attendant in the light of clinical data presented by the patient and the diagnostic and treatment options available. This means that RCOG Guidelines are unlike protocols or guidelines issued by employers, as they are not intended to be prescriptive directions defining a single course of management. Departure from the local prescriptive protocols or guidelines should be fully documented in the patient’s case notes at the time the relevant decision is taken.