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The Role For Emergency Cerclage: What Does the Data Really Show?
E.R. Norwitz
Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham & Women's
Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A.
Introduction
Cervical incompetence is defined as the inability to support a pregnancy to term due to a functional or
structural defect of the cervix (1). It is a clinical diagnosis characterized by acute, painless dilatation of
the cervix usually in the mid-trimester culminating in prolapse and/or premature rupture of the
membranes (PROM) with resultant preterm and often previable delivery. Cervical cerclage has become
the mainstay for the management of cervical incompetence.
Cervical Anatomy
Embryologically, the body and cervix of the uterus are derived from fusion and recanalization of the
th
month of pregnancy.
Histologically, the cervix consists of fibrous connective tissue, muscle, and blood vessels. Muscular
connective tissue constitutes approximately 15% of the cervical stroma, but is not uniformly distributed
throughout the cervix, constituting approximately 30%, 18%, and 7% of the upper, mid, and lower thirds
of the cervix, respectively (2). Conversely, the fibrous connective tissue content of the cervical stroma
increases as one moves from the external os to the uterine corpus, and it this component that is believed
to confer tensile strength to the cervix. Defects in tensile strength are thought to lead to premature
cervical dilatation and pregnancy loss.
Etiology
abnormalities (cervical hypoplasia, in utero diethylstilbestrol [DES] exposure), traumatic abnormalities
(prior surgical or obstetric trauma), and connective tissue abnormalities (Ehlers-Danlos syndrome). Of
note, a history of first trimester abortion does not appear to be a risk factor for cervical incompetence if
the abortion was performed by a skilled operator using local anesthesia and laminaria (3-5).
Incidence
It is estimated that cervical incompetence will complicate anywhere from 0.1% to 2% of all pregnancies
(1,6-8), and is thought to be responsible for approximately 15% of habitual immature deliveries between
16 and 28 weeks of gestation (9).
Indications
Suspected cervical incompetence remains the only acceptable indication for cervical cerclage. Indications
can be classified as follows:
(1) Prophylactic (elective) cervical cerclage is indicated in asymptomatic women with a history of prior
pregnancy loss and/or preterm delivery due to cervical incompetence. This is because the probability of
recurrence in a subsequent pregnancy is 15-30% (1,9). Prophylactic cervical cerclage may be placed prior
to pregnancy, but is more commonly placed between 10-16 weeks’ gestation.
(2) Asymptomatic women with sonographic evidence of cervical shortening and/or funneling may also
benefit from cervical cerclage (often called urgent cerclage), although the data in this regard is
controversial. There are several retrospective studies suggesting that cervical cerclage in asymptomatic
women with short cervical length on endovaginal ultrasound may improve perinatal outcome (10-13).
These studies reported an overall reduction in the incidence of preterm delivery in women identified as
having a short cervix by transvaginal sonography before 24 weeks’ gestation and subsequently treated
with cerclage to approximately 10% of controls. However, more recent studies suggest that cerclage does
not prevent preterm delivery in women at high-risk for preterm birth on the basis of cervical shortening
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(14,15). Moreover, one study showed a higher rate of preterm PROM in women who received a cerclage
as compared with those without cerclage (15). Further studies are awaited to clarify this issue.
(3) Emergency (salvage) cervical cerclage refers to placement of a cerclage in the setting of significant
cervical dilatation and/or effacement prior to 28 weeks’ gestation and in the absence of labor. It is this
entity which will discussed in further detail below.
Contraindications to Emergency Cervical Cerclage
Absolute contraindications to emergency cerclage are summarized in Table 1. Factors such as placenta
previa, a mucopurulent cervical discharge with membrane opacification, fetal membranes prolapsing
through the cervical os, and/or intrauterine fetal growth restriction (IUGR) may be regarded as relative
contraindications. ACOG supports cervical cerclage placement up to 28 weeks’ gestation (16). However,
many practitioners would not recommend emergent cervical cerclage placement beyond the limit of fetal
viability (i.e., 24 weeks’ gestation), because the potential for harm likely outweighs the potential benefit
(17).
Complications of Emergency Cervical Cerclage
Complications of emergency cerclage increase with increasing gestational age and cervical dilatation
(18), and are summarized in Table 2. In general, cervical cerclage is associated with increased obstetric
interventions, including higher rates of admission to hospital, long-term tocolysis, induction of labor, and
cesarean delivery (8,19). Puerperal infection occurs in approximately 6% of patients with cerclage, which
is twice as common as the incidence in gestational age-matched controls without cerclage (8,19).
Technical Considerations
(1) Preoperative considerations. An ultrasound should be performed to exclude gross structural
anomalies (such as anencephaly) and/or fetal demise. Written consent should be obtained.
(2) Amniocentesis? Intraamniotic infection is an absolute contraindication to cervical cerclage, and the
presence of bacteria on Gram stain or a positive culture from preoperative amniocentesis is associated
with a failure rate of >90% (20). Romero et al (21) showed that microbial invasion of the amniotic fluid
can be expected in more than 50% of patients with cervical dilatation >2 cm between 14 and 24 weeks’
gestation. Importantly, the spectrum of cultured organisms in their study included Ureaplasma
urealyticum, Gardenerella vaginalis, Fusobacterium sp., Mycoplasma hominis, and Candida albicans,
all organisms thought to be normal flora of the lower genital tract. All patients in this series with
amniotic infection confirmed by amniocentesis delivered within 1 week. Despite these data, preoperative
amniocentesis in asymptomatic parturients with cervical incompetence should not be regarded as an
absolute prerequisite for emergency cerclage placement. The data regarding cervicovaginal cultures and
the efficacy of emergency cerclage is similarly controversial.
(3) Intraoperative considerations. Many practitioners will recommend an observation period of 12-24
hours before placement of an emergency cerclage to exclude preterm labor, ruptured membranes, and
chorioamnionitis (22), although it is not clear that is necessary. Confirmation of fetal viability is required
both immediately before and after the procedure, either by auscultation or by ultrasound. Regional
anesthesia is preferred, because of the decreased maternal morbidity as compared with general
endotracheal anesthesia. Prophylactic tocolysis may be used to inhibit transient uterine contractions
associated with cerclage placement, but there is no objective evidence that tocolysis improves outcome.
Moreover, although there are no trials to support their use in prophylactic cerclage procedures, most
series reporting higher fetal salvage rates with emergency cerclage have used perioperative broadspectrum antibiotics with a view to decreasing the risk of intra-amniotic infection (refer Table 3).
(4) Prolapsing membranes. If the fetal membranes are found to be prolapsing through the external os,
the risk of iatrogenic rupture of the fetal membranes may be as high as 40-50%. Trendelenburg position
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(23), filling the bladder (24), placement of a 30-mL Foley catheter (25) or moistened sponge forceps into
the cervical os (26), and/or therapeutic amniocentesis (27-29) can be used to reduce the fetal membranes
prior to cerclage placement, with variable success.
(5) Choice of cervical cerclage. There are no well-designed, prospective, randomized, controlled clinical
trials comparing Shirodkar and McDonald cerclage. As such, the decision of which technique to use can
be left to the discretion of the operator. Under certain circumstances, however, one or other technique
may be preferable. For example, if the cervix is very short or lacerated, a Shirodkar cerclage may be
technically easier to place.
(6) Postoperative recommendations. Weekly or biweekly follow-up visits are probably sufficient in the
absence of clinical symptoms. Cervical assessment may be by bimanual examination or by ultrasound.
Bedrest and “pelvic rest” (no coitus, tampons, or douching) are usually recommended until a favorable
gestational age is reached, but without proven benefit. In the absence of obstetric complications, the
cerclage is usually removed electively in the office at around 37 weeks’ gestation.
Efficacy of Emergency Cervical Cerclage: What Does the Data Really Show?
It is generally accepted that cerclage placement for cervical incompetence is best performed prior to
cervical dilatation and effacement. At least two studies have reported a lower success rate (50% and
59%) with emergency cerclage as compared with prophylactic cerclage (86% and 81%), although in
neither studies was the number of cases sufficient to reach statistical significance (30,31). If emergency
cerclage procedures truly have a lower success rate, it is tempting to conclude that the cerclage was
placed too late. However, an equally plausible explanation would be that some prophylactic cerclages are
placed in women who do not need them and, as such, are bound to have more favorable outcomes.
It is commonly believed that emergency cerclage may be the only hope for prolonging gestation in
parturients with advanced cervical changes in the second trimester with or without prolapsed membranes
(“eminence-based medicine”). However, emergency cerclage is a surgical procedure with well-defined
operative risks. Whether such an approach is superior to bedrest and expectant management remains
unclear (evidence-based medicine). The weight of evidence in the published literature suggests that
emergency cerclage is associated with a fetal survival rate of 22-100% (Table 3). However, such data
comes exclusively from retrospective descriptive studies. There are as yet no published randomized
controlled trials (RCT) specifically addressing the issue of emergency cerclage. Some authors would
argue that such an RCT would be unethical as it would deprive patients of standard therapy (32); others
would argue that it is unethical for us to continue to pretend that emergency cerclage has ever been
proven to be beneficial in a rigorous, scientific fashion. In the absence of incontrovertible evidence
demonstrating a benefit, emergency cervical cerclage should be used judiciously and only after extensive
and comprehensive patient counseling.
Conclusions
Emergency cervical cerclage remains an important part of the obstetric armamentarium for the
management of cervical incompetence. However, it is a surgical procedure without proven benefit and
with well-defined operative risks. As such, until adequate clinical trials are available demonstrating a
clear benefit, emergency cerclage should be used judiciously and only after extensive and comprehensive
patient counseling.
References
1. Norwitz ER, Greene MF, Repke JT. Cervical Cerclage – Elective and Emergent. ACOG Update 1999;
24:1-11.
2. Danforth DN. The fibrous nature of the human cervix, and its relation to the isthmic segment in gravid
and nongravid uteri. Am J Obstet Gynecol 1947; 53:541-60.
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3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Harlap S, Shiono PH, Ramcharan MS, Berendes H, Pellegrin F. A prospective study of spontaneous
fetal loss after induced abortion. N Engl J Med 1979; 301:677-81.
Cousins L. Cervical incompetence, 1980: A time for reappraisal. Clin Obstet Gynecol 1980; 23:467-79.
Grimes DA, Schulz KF, Cates WJ. Prevention of uterine perforation during curettage abortion. JAMA
1984; 251:2108-11.
Harger JH. Cervical cerclage: Patient selection, morbidity, and success rates. Clin Perinatol 1983:
10:321-41.
Golan A, Barnan R, Wexler S, Langer R, Bukovsky I, David MP. Incompetence of the uterine cervix.
Obstet Gynecol Survey 1989; 44:96-107.
American College of Obstetricians and Gynecologists. Preterm Labor. ACOG Technical Bulletin 206.
Washington, D.C.: ACOG, 1995.
Shortle B, Jewelewicz R. Cervical incompetence. Fertil Steril 1989; 52:181-8.
Guzman ER, Mellon C, Vintzileos AM, Ananth CV, Walters C, Gipson K. Longitudinal assessment of
endocervical canal length between 15 and 24 weeks’ gestation in women at risk for pregnancy loss or
preterm birth. Obstet Gynecol 1998; 92:31-7.
Heath VCF, Souka AP, Erasmus I, Gibb DMF, Nicolaides KH. Cervical length at 23 weeks of
gestation: The value of Shirodkar suture for the short cervix. Ultrasound Obstet Gynecol 1998; 12:31822.
Hibbard JU, Snow J, Moawad AH. Short cervical length by ultrasound and cerclage. J Perinatol 2000;
3:161-5.
Althuisius SM, Dekker GA, van Geijn HP, Bekedam DJ, Hummel P. Cervical incompetence
prevention randomized cerclage trial (CIPRACT): Study design and preliminary results. Am J Obstet
Gynecol 2000; 183:823-9.
Berghella V, Daly SF, Tolosa JE, et al. Prediction of preterm delivery with transvaginal
ultrasonography of the cervix in patients with high-risk pregnancies: Does cerclage prevent
prematurity? Am J Obstet Gynecol 1999; 181:809-15.
Hassan SS, Romero R, Maymon E, et al. Does cervical cerclage prevent preterm delivery in patients
with a short cervix? Am J Obstet Gynecol 2001; 184:1325-9.
American College of Obstetricians and Gynecologists. Cervical cerclage. ACOG Criteria Set Number
18. Washington, D.C.: ACOG, 1996.
MacDougall J, Siddle N. Emergency cervical cerclage. Br J Obstet Gynecol 1991; 98:1234-8.
Treadwell MC, Bronsteen RA, Bottoms SF. Prognostic factors and complication rates for cervical
cerclage: A review of 482 cases. Am J Obstet Gynecol 1991; 165:555-8.
Final report of the Medical Research Council/Royal College of Obstetricians and Gynaecologists
multicentre randomised trial of cervical cerclage. MRC/RCOG Working Party on Cervical Cerclage.
Br J Obstet Gynaecol 1993; 100:516-23.
Mays JK, Figueroa R, Shah J, Khakoo H, Kaminsky S, Tejani N. Amniocentesis for selection before
rescue cerclage. Obstet Gynecol 2000; 95:652-5.
Romero R, Gonzalez R, Sepulveda W, et al. Microbial invasion of the amniotic cavity in patients with
suspected cervical incompetence: Prevalence and clinical significance. Am J Obstet Gynecol 1992;
167:1086-91.
Barth WH Jr. Cervical incompetence and cerclage: Unresolved controversies. Clinical Obstet Gynecol
1994; 37:831-41.
Olatunbosun OA, Dyck F. Cervical cerclage operation for a dilated cervix. Obstet Gynecol 1981;
57:166-70.
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24. Scheerer LJ, Lam F, Bartolucci L, Katz M. A new technique for reduction of prolapsed fetal
membranes for emergency cervical cerclage. Obstet Gynecol 1989; 74:408-10.
25. Sher G. Congenital incompetence of the cervical os: Reduction of bulging membranes with a modified
Foley catheter. J Reprod Med 1979; 22:165-7.
26. McDonald IA. Suture of the cervix for inevitable miscarriage. J Obstet Gynecol Br Emp 1957; 64:34650.
27. Goodlin RC. Cervical incompetence, hourglassing membranes, and amniocentesis. Obstet Gynecol
1979; 54:748-50.
28. Katz M, Chez RA. Reducing prolapsed membranes. Contemp Ob Gyn 1990; 35:48-53.
29. Locatelli A, Vergani P, Bellini P, Strobelt N, Arreghini A, Ghidini A. Amnioreduction in emergency
cerclage with prolapsed membranes: Comparison of two methods for reducing the membranes. Am J
Perinatol 1999; 16:73-7.
30. Harger JH. Comparison of success and morbidity in cervical cerclage procedures. Obstet Gynecol
1980; 56:543-8.
31. Goldstein DP, Wolff RJ. The incompetent cervix: A survey of survivors. Obstet Gynecol 1964; 23:7527.
32. Olatunbosun OA, Al-Nuaim L, Turnell RW. Emergency cerclage compared with bed rest for advanced
cervical dilatation in pregnancy. Int Surg 1995; 80:170-4.
33. Kuhn RJP, Pepperell RJ. Cervical ligation: A review of 242 pregnancies. Aust N Z J Obstet Gynaecol
1977; 17:79-83.
34. Robrecht D, Hillemans HG, Deichsel W, et al. Notfall-cerclage: Definition, technisches vorgehen und
prognose [Emergency cerclage: Definition, technical procedure, and prognosis]. Geburtshilfe u
Frauenheilk 1979; 39:869-74.
35. Charles D, Edwards WR. Infectious complications of cervical cerclage. Am J Obstet Gynecol 1981;
141:1065-71.
36. Conradt A, Weidinger H, Bodenstein J. Tokolyse bei notfall-cerclage [Tocolysis in emergency
cerclage]. Geburtshilfe u Frauenheilk 1982; 42:291-6.
37. Goodlin RC. Surgical treatment of patients with hour-glass shaped or ruptured membranes before the
25th week of gestation. Surg Gynecol Obstet 1987; 165:410-2.
38. Barth WH Jr, Yeomans ER, Hankins GDV. Emergent cerclage. Surg Gynecol Obstet 1990; 170:323-6.
39. Higuchi M, Hirano H, Maki M. Emergency cervical cerclage using a metreurynter in patients with
bulging membranes. Acta Obstet Gynecol Scand 1992; 71:34-7.
40. Mitra AG, Katz VL, Bowes WA Jr, Carmichael S. Emergency cerclages: A review of 40 consecutive
procedures. Am J Perinatol 1992; 9:142-5.
41. Wong GP, Farquharson DF, Dansereau J. Emergency cervical cerclage: A retrospective review of 51
cases. Am J Perinatol 1993; 10:341-6.
42. Aarts JM, Brons JT, Bruinse HW. Emergency cerclage: A review. Obstet Gynecol Surv 1995; 50:45969.
43. Lipitz S, Libshitz A, Oelsner G, et al. Outcome of second-trimester, emergency cervical cerclage in
patients with no history of cervical incompetence. Am J Perinatol 1996; 13:419-22.
44. Schorr SJ, Morales WJ. Obstetric management of incompetence cervix and bulging fetal membranes. J
Reprod Med 1996; 41:235-8.
45. Wu MY, Yang YS, Huang SC, Lee TY, Ho HN. Emergent and elective cervical cerclage for cervical
incompetence. Int J Gynaecol Obstet 1996; 54:23-9.
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46. Benifla JL, Goffinet F, Darai E, Proust A, De Crepy A, Madelenat P. Emergency cervical cerclage after
20 weeks’ gestation: A retrospective study of 6 years’ practice in 34 cases. Fetal Diagn Ther 1997;
12:275-8.
47. Yip SK, Fung HY, Fung TY. Emergency cervical cerclage: A study between duration of cerclage in
situ with gestation at cerclage, herniation of forewater, and cervical dilatation at presentation. Euro J
Obstet Gynecol Reprod Biol 1998; 78:63-7.
48. Kurup M, Goldkrand JW. Cervical incompetence: Elective, emergent, or urgent cerclage. Am J Obstet
Gynecol 1999; 181:240-6.
49. Caruso A, Trivellini C, De Carolis S, Paradisi G, Mancuso S, Ferrazzani S. Emergency cerclage in the
presence of protruding membranes: Is pregnancy outcome predictable? Acta Obstet Gynecol Scand
2000; 79:265-8.
50. Tsatsaris V, Senat MV, Gervaise A, Fernandez H. Balloon replacement of fetal membranes to facilitate
emergency cervical cerclage. Obstet Gynecol 2001; 98:243-6.
Table 1. Absolute Contraindications to Emergency Cervical Cerclage
Table 2. Complications of Emergency Cervical Cerclage
Table 3. Efficacy of Emergency Cervical Cerclage¶