[Prevention of preterm birth by uterine cervical cerclage]

To review the scientific literature on cervical insufficiency and indications of cervical cerclage cervix.

The PubMed database, the Cochrane Library and the recommendations from the French and international obstetrical societies between 1972 and June 2016 have been consulted.

Cervical insufficiency is a pathophysiological concept and to date no consensual definition is available: the diagnosis is clinical and discussed retrospectively in case of patients with a history of late miscarriages and/or spontaneous preterm delivery, with asymptomatic dilatation of the cervix (professional consensus). The risk of preterm birth is higher in case of surgical cold-knife conisation as compared to loop electrosurgical excision (LE3) and laser vaporization has a negligible impact (LE3). In patients with a history of late pregnancy loss or preterm birth, investigations for the diagnosis of uterine malformation are recommended (grade C). No investigation is recommended for the diagnosis of a cervical insufficiency (professional consensus). A history-indicated cerclage is not recommended in case of only past history of conisation (grade C), uterine malformation (professional consensus), isolated history of preterm delivery (grade B) or twin pregnancies in primary (grade B) or secondary (grade C) prevention of preterm birth. A history-indicated cerclage is recommended for single pregnancy with a history of at least three late miscarriages or preterm deliveries (grade A). In case of history of one or two late miscarriages or preterm deliveries, there are not sufficient arguments to recommend a history-indicated cerclage (professional consensus). Further studies are needed. The ultrasound-indicated cerclage is not recommended in case of short cervical length during the 2nd trimester of single pregnancy without past history of gynecologic or obstetrical event (grade B). In case of past history of a single pregnancy delivery before 34 weeks gestation (WG), ultrasound cervical length screening is recommended between 16 and 22 WG in order to propose a cerclage in case of length<25mm before 24 WG (grade C). Ultrasound-indicated cerclage is not recommended for multiple pregnancy with a short cervix (grade B). Emergency cerclage using the MacDonald technique is recommended during the second trimester of pregnancy in case of major changes of the cervix, with or without protrusion of the fetal membranes, but without premature rupture of membranes or chorioamnionitis (grade C). Tocolysis and antibiotics during cerclage should be considered individually (professional consensus). There is no reason to recommend a period of expectative before considering an emergency cerclage (professional consensus). A maximum gestational age to perform a cerclage cannot be recommended (professional consensus). A cervico-isthmic cerclage can be discussed in case of failure of MacDonald cerclage (professional consensus). Scientific data are insufficient to recommend or not a vaginal bacteriological analysis before performing a cerclage (professional consensus). The use of double cerclage does not improve perinatal outcome (NP3) and is not recommended (grade C). There is insufficient scientific argument to recommend a type of stitch over another (grade C). The available data are not in favor of a superiority of the Shirodkar cerclage in case of history- or ultrasound-indicated cerclage and the MacDonald cerclage is firstly recommended because technically easier and less risky (grade C). Overall, complications of cerclage are rare but potentially serious. The occurrence of complications is no different between the history-indicated and echo-indicated cerclage (LE4). There is no scientific evidence on the benefit of bed rest and adjuvant treatments (antibiotics or indomethacin) during history or ultrasound-indicated cerclage (professional consensus).

Available data in the literature about cervical cerclage are generally of low level of evidence.