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OBSTETRICS FEATURE
Cervical Incompetence Update
Kara Beth Thompson, MD; Jennifer Keehbauch, MD
In the face of diagnostic challenges and
questions regarding treatment risks versus benefits for the neonate, what is the
current consensus on the criteria and
management for incompetent cervix?
H
istorically, cervical incompetence was defined as passive,
painless cervical dilatation in
the second trimester with no
rupture of membranes, preterm
labor, bleeding, or chorioamnionitis. Today, the
cervix is viewed more as a dynamic organ, with
incompetence occurring along a continuum as
a result of multiple factors. Estimates of prevalence are derived from the ratio
FOCUSPOINT
of cerclage procedures to deliveries, which is as high as 1% of
US pregnancies, or 40,000 cerToday, the cervix
clages performed annually.1
Risk factors for cervical
is viewed more as
incompetence are listed in
a dynamic organ,
Table 1. However, insufficiency
with incompetence
may also occur in the absence
of these risk factors. Thereoccurring along
fore, the continuum of cervia continuum as a
cal incompetence may also be
result of multiple
related to additional, yet-undefactors.
fined processes such as infection, bacterial colonization,
hormonal changes, inflammation, or genetic predisposition.
in light of recent ultrasonographic fi ndings,
this definition is being challenged.
Transvaginal ultrasonography is a safe, reproducible method for objectively assessing cervical length, and it appears to be superior to
digital vaginal examination or abdominal
ultrasonography in this regard. Transvaginal
ultrasonography has become the “gold standard” for cervical evaluation. The cervix in pregnancy follows a predictable pattern of effacement and dilation. Effacement begins at the
internal cervical os and progresses in a “funneling” manner toward the external cervical os.
On sonograms, this initially appears as a
Y-shaped “beaking” of the cervical canal sidewalls that develops into a U-shaped space.
The cervical length usually remains stable
until the early third trimester and shortens progressively thereafter. Normal cervical lengths
between 22 and 32 weeks’ gestation have been
observed at 45 mm for the 90th percentile and
25 mm for the 10th percentile (Table 2).2
Serial ultrasonographic examination of cervical length can predict the risk of preterm
delivery; the shorter the cervical length, the
higher the likelihood ratio for preterm delivery.4
Using a value of less than 25 mm for cervical
TABLE 1. Risk Factors for
Cervical Insufficiency 2,3
• Gynecologic surgery
LEEP
Cone biopsy
• Obstetric trauma
DIAGNOSIS
Classically, cervical incompetence was diagnosed based on clinical history—recurrent
pregnancy loss in the second trimester, with
each loss occurring at an earlier gestational age
than the preceding one and lacking painful
contractions or other inciting events. However,
Cervical laceration
Prolonged 2nd stage of labor
Overdilation of cervix during pregnancy termination
• DES exposure
• Müllerian anomalies
• Collagen/elastin deficiencies
Kara Beth Thompson, MD, is a member of the teaching faculty,
Christian Internal Medicine Specialization Program, Mbingo
Baptist Hospital, Cameroon. Jennifer Keehbauch, MD, is
Associate Director, Florida Hospital Family Medicine Residency Program, Orlando.
14 The Female Patient | VOL 34 NOVEMBER 2009
• Multiple gestation
• History of preterm birth or second-trimester loss
Abbreviations: DES, diethylstilbestrol; LEEP, loop electrical excisional
procedure.
All articles are available online at www.femalepatient.com.
THOMPSON and KEEHBAUCH
length provides a balance between sensitivity
and specificity, maintaining a positive predictive value for preterm birth of 55%.5
Criteria for cervical incompetence include:
• History of recurrent second-trimester losses
in the absence of other inciting events
• Current second-trimester presentation with
acute, advanced cervical effacement and
dilation without painful contractions
• Ultrasonographic evidence of progressive
cervical effacement (shortening to less than
25 mm or funneling).
Low-risk patients are identified incidentally
on transvaginal ultrasonography and have no
suggestive history, no uterine malformations,
no history of preterm birth or second-trimester loss, and a singleton gestation.6 Women at
highest risk have 3 or more preterm births or
second-trimester losses or have a history of
preterm birth or second-trimester loss in the
setting of a cervical length less than 25 mm.7
TREATMENT
Nonsurgical Treatment
Nonsurgical options may reduce the risk of
preterm delivery in women with cervical
incompetence. Reduction of activity or complete bed rest, avoidance of sexual inter-
TABLE 2. Median Cervical Length by Gestational Age2
14−22 weeks
24−28 weeks
>32 weeks
35−40 mm
35 mm
30 mm
course, and cessation of tobacco use have
been recommended. The use of indomethacin (100 mg once, followed by 50 mg every 6
hours for 48 hours) has been associated with
a reduction in delivery before 35 weeks and
decreased preterm delivery by 86% in women
who presented with a shortened cervix prior
to 24 weeks.8
Surgical Treatment
Cerclage placement is the mainstay for preterm birth prevention in women with cervical
insufficiency. Approaches and placements of
the cerclage stitch differ, and no single technique has been demonstrated to be superior
to others.9
The most popular transvaginal approach is
the McDonald technique, which uses local or
regional anesthesia to place monofi lament
suture (polypropylene) or polyester fiber tape
at the cervicovaginal junction. A weighted
Coding for Cervical Incompetence
This article discusses cervical incompetence and the diagnosis
and treatment during the current pregnancy. The following codes
should be used:
649.7
Cervical shortening
[0,1,3]
654.4 Cervical incompetence
[0–4]
Presence of Shirodkar suture with or without mention of
cervical incompetence
Fifth Digit Required for Codes 649.7 and 654.4
0
Unspecified as to episode of care or not applicable
1
Delivered, with or without mention of antepartum
condition
2
Delivered, with mention of postpartum condition
3
Antepartum condition or complication (patient still
pregnant at end of episode of care)
4
Postpartum condition or complication (patient delivered
during previous episode of care)
The following V codes should be used when performing the transvaginal ultrasonography or surgical treatment. Codes V23.41 and/or
V23.49 should be used instead of V23.4.
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and
Philip N. Eskew Jr, MD
V23
V23.4
Supervision of high-risk pregnancy
Pregnancy with other poor obstetric history
Pregnancy with history of other conditions classifiable
to 630–676
V23.41 Pregnancy with history of preterm labor
V23.49 Pregnancy with other poor obstetric history
V89.05 Suspected cervical shortening not found
The following are the Current Procedural Terminology (CPT) codes
referred to in this article:
76817 Ultrasound, pregnant uterus, real time with image
documentation, transvaginal
(For nonobstetrical transvaginal ultrasound, use 76830)
59320 Cerclage of cervix, during pregnancy; vaginal
59325 Cerclage of cervix, during pregnancy; abdominal
Philip N. Eskew Jr, MD, is past member, CPT Editorial
Panel; past member, CPT Advisory Committee; past chair,
ACOG Coding and Nomenclature Committee; and instructor,
CPT coding and documentation courses and seminars.
The Female Patient | VOL 34 NOVEMBER 2009 15
Cervical Incompetence Update
Patient at risk for incompetent cervix
History of 3 PTBs
or 2nd-trimester
losses
1 to 2 PTBs or 2nd-trimester
losses with current
singleton pregnancy
Painless cervical dilation
or bulging membranes
<24 weeks
Elective cerclage
at 12–14 weeks
Obtain TVUS at
14–24 weeks
Emergent
cerclage
CL <25 mm
CL >25 mm
Therapeutic cerclage
at 14–24 weeks
Repeat ultrasonography
at 1–2 week intervals
FIGURE. Treatment algorithm for incompetent cervix.1
Abbreviations: CL, cervical length; PTB, preterm birth; TVUS, transvaginal ultrasonography.
speculum is inserted into the
vagina, and Sims retractors are
used anteriorly for vaginal
retraction. The cervix is grasped
gently with an Allis clamp or
Approaches and
ring forceps for traction. Startplacements of
ing at the 12 o’clock position, 4
the cerclage stitch
or 5 successive bites are taken
in a “purse-string” manner.
differ, and no single
The suture is tied anteriorly
technique has been
and trimmed. The Shirodkar
demonstrated to be
procedure involves placement
superior to others.
of the suture as close to the
internal os as possible after dissection of the rectum and bladder from the cervix. After the
suture is inserted, the mucosa
is replaced over the knot. The
McDonald procedure is generally favored over
the Shirodkar procedure because of the former’s
ease of suture placement.9
In transabdominal approaches via laparotomy or laparoscopy, the suture is placed in the
cervicoisthmic region after dissection of the
bladder away from the lower uterine segment.
This invasive procedure carries a higher risk of
complications (eg, hemorrhage), and it is generally reserved for patients who fail transvaginal
placement, have congenital cervical hypopla-
FOCUSPOINT
16 The Female Patient | VOL 34 NOVEMBER 2009
sia, or have substantial scar tissue from prior
surgery or trauma. One study has shown favorable outcomes from transvaginal placement of
cervicoisthmic cerclages.10
Some studies have demonstrated an overall increase in cervical length, while others
have been able to show an increase in the
distal cervix only. However, choice of method
or placement of the cerclage closer to the
internal os does not appear to significantly
affect outcomes.9,11
Indications and Contraindications—The figure on this page outlines the decision tree for
cerclage. Elective (prophylactic) cerclage is
generally placed at 13 to 16 weeks’ gestation
based on historical factors alone. This is usually reserved for patients with a history of 3 or
more unexplained second-trimester losses.
The presence of a live fetus without anomalies is confi rmed prior to stitch placement
(Table 3).1,12-14
Urgent (therapeutic) cerclage is recommended for patients who present with ultrasonographic evidence of cervical shortening
(less than 25 mm) or funneling. Ultrasonographic evaluation is usually performed due
to risk factors for preterm delivery or symptoms (eg, contractions, pelvic pressure, vaginal spotting). Randomized trials for this
All articles are available online at www.femalepatient.com.
Cervical Incompetence Update
TABLE 3. Results of Trials for Elective Cerclage
Type of Trial
Patient Population
Findings
Reference
RCT
67 women with history
of delivery <34 weeks
No difference in preterm
births <35 weeks
12
Meta-analysis
2,190 women in 6 trials
No difference in preterm births
<34 weeks or neonatal survival
13
Cohort
225 women at 14−26 weeks
with ≥1 cm of dilation
Fewer preterm deliveries
<28 weeks
Increased neonatal survival
14
Abbreviation: RCT, randomized controlled trial.
subset of patients have demonstrated variable outcomes
Until data demon(Table 4).7,14-17
Emergent cerclage is perstrate a reduction
formed in women who present
in preterm births and
with symptoms of cervical
improved neonatal
incompetence, eg, pelvic pressure, clear vaginal discharge,
outcomes, discuss
cervical dilation of 2 cm or
options and risks to
more, absence of regular uterdetermine how to
ine contractions (Table 5).18-20
At this stage of cervical insuffimanage cervical
ciency, the membranes are
incompetence in
often at or beyond the external
a given case.
cervical os. There are various
methods for reducing the
membranes back into the
intrauterine cavity: A Foley catheter can be
placed in the bladder or the cervical os to displace the membranes caudally, or an inflated
FOCUSPOINT
balloon can be inserted under epidural anesthesia with the patient in the Trendelenburg
position. Amniocentesis with glucose level,
Gram stain, and interleukin studies should be
considered to rule out subclinical intra-amniotic infection due to the exposed membranes.
Transabdominal amniocentesis can also serve
to reduce the membranes via amnioreduction.
Complications—The most common complications of cerclage placement are rupture of membranes, chorioamnionitis, and displacement of
the suture. Incidences vary with procedure indication and timing. Rupture of membranes has
been reported in 1% to 18% of elective, 3% to
65% of urgent, and 0% to 51% of emergent cerclage placements. Chorioamnionitis developed
in 1% to 6%, 30% to 35%, and 9% to 37% of procedures, respectively. Displacement of the
suture occurred in 3% to 13% of elective cerclage procedures.3
TABLE 4. Results of Trials for Urgent Cerclage
Type of Trial
Patient Population
Findings
Reference
RCT
113 low-risk women at 16−24 weeks with
cervical length <25 mm OR membrane
prolapse >25% of canal length
No difference in gestational age
at delivery or perinatal outcome
15
RCT
35 high-risk women with cervical length
<25 mm at 27 weeks
Fewer preterm deliveries <34 weeks
16
RCT
253 low-risk women at 22–24 weeks
with cervical length <15 mm
No difference in gestational age at
delivery or neonatal morbidity
17
Meta-analysis
607 women from studies in references 6, 15−17
Fewer preterm deliveries <37 weeks
7
Cohort
225 women at 14−26 weeks with ≥1 cm
of dilation
Fewer preterm deliveries <28 weeks
Increased neonatal survival
14
Abbreviation: RCT, randomized controlled trial.
18 The Female Patient | VOL 34 NOVEMBER 2009
All articles are available online at www.femalepatient.com.
THOMPSON and KEEHBAUCH
TABLE 5. Results of Trials for Emergent Cerclage
Type of Trial
Patient Population
Findings
Reference
Observational
35 women with >2 cm of cervical
dilation and no labor at 20−22 weeks
Survival of 85.7% of neonates
18
Observational
46 women at 18−26 weeks with
cervical length <15 mm and >2 cm
of cervical dilation
Fewer preterm deliveries and
increased neonatal survival
19
RCT
23 women at 27 weeks with membranes
at or beyond the external os
Fewer deliveries at 34 weeks
No difference in neonatal survival
20
Abbreviation: RCT, randomized controlled trial.
CONCLUSION
Until further data demonstrate a reduction in
preterm births and improved neonatal outcomes, physicians and patients must discuss
options, risks, and outcomes to determine how
best to manage cervical incompetence in a
given case. Current evidence supports the
following recommendations: (1) serial transvaginal ultrasonographic evaluation for cervical length should be considered beginning
at 14 to 20 weeks’ gestation in women with risk
factors for cervical incompetence; and (2) elective cerclage should be considered in patients
with a history of 3 preterm births or second-trimester losses or a singleton pregnancy
and short cervix in the second trimester.1,6,15,20
Dr Thompson reports no actual or potential
conflicts of interest in relation to this article.
Dr Keehbauch served as a consultant to
Schlesinger Associates and Maximus, is a stockholder in Pfizer, and is on the speakers bureau
for Novartis.
8.
9.
10.
11.
12.
13.
14.
15.
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The Female Patient | VOL 34 NOVEMBER 2009 19