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.
