Transvaginal Assessment of the Short and Funneled Cervix

Professor Curtis L Lowery MDDepartment of Ob/Gyn UAMS Collage of Medicine

Preterm Births•10% of all newborns

•75% of all neonatal deaths and morbidity

•Causes multifactorial

•Risk scoring fails to predict 70% of preterm births

Lockwood CJ, Kuczynski E. Markers of risk for preterm delivery. J Perinat Med 1999;27:5-20. Besinger RE. Preterm labor, premature rupture of membranes, and cervical incompetence.Curr Opin Obstet Gynecol 1993;5:33-9.

Cervical Insufficiency

The inability of the uterine cervix to retain a pregnancy to term. Controversy exists in the medical literature pertaining to issues of pathophysiology, screening, and management of cervical insufficiency.

Cervical insufficiency• The terms "cervical insufficiency" and

"cervical incompetence" have been used to describe the inability of the uterine cervix to retain a pregnancy in the absence of contractions or labor.

• The diagnosis of "cervical incompetence" was made when patients experienced painless cervical dilation after the first trimester with subsequent expulsion of the pregnancy out of the uterus without contractions or labor.

Incidence• Toaff et al

– 1 in 54 pregnant women

• Little and Tenney– 1 in 2000 pregnancies

• Shortle– 8 to 15% of habitual Ab

Learning Objectives• Review the recommended technique

for performing TVU

• Review the literature regarding indications for TVU

• Review the literature regarding the indications for treatment of the shortened of funneled cervix

• Outline reasonable approach to therapy.

TVU (Transvaginal ultrasound) •Cervical length and funneling

•Can TVU predict preterm delivery?

•Can TVU help manage the patient with incompetent cervix?

Confusion over diagnosis• It is important to differentiate preterm

labor from cervical incompetence.

• While transvaginal ultrasound may be able to predict preterm labor we have been unable to successfully reduce the incidence of this obstetrical problem!

Transvaginal Ultrasound•TVU important development

•Predicts preterm birth

•Better than digital examinations

Cervical length by TVU•Empty patient bladder •Condom-covered ultrasound probe •Anterior fornix of the vagina sagittal view of the cervix•Avoid excessive pressure on the cervix

•Enlarge the image so that the cervix occupies at least 2/3 of the image •Measure the cervical length from the internal to the external os along the endocervical canal shortest best measurement in millimeters

Calculate Funneling

Transvaginal Ultrasound

CL during pregnancy• Mean CL of 35 to 40 mm from 14 to 30

weeks

• Lower 10th percentile 25 mm

• Natural shortening of CL after 30 weeks

• CL <25 mm is abnormal between 14 and 24 weeks

• Correlation between CL and PTB

PTB and CL

Vincenzo Berghella, MD Contemporary OB/Gyn April 2004

Screening with TVU• Screening between 10 and 14 weeks

is poor (5% incidence)

• Short cervix or funneling usually develops between 18 to 22 weeks.

• Best to perform TVU screening between 14-18 weeks

• Limited to high risk only

High Risk Patients• prior PTB

• müllerian anomaly

• two or more D&Es

• DES exposure

• cone biopsy

• twin gestation

McDonald Cerclage 1957

• Purse string suture

• Initially described in women with partial cervical dilation

• Improved outcomes reported by McDonald when stitch was placed prior to documented cervical change

Complications of Cerclage Placement

• Direct– Bleeding– Infection– Inadvertent rupture of membranes– Preterm labor– Cervical dystocia – Bladder injury– Suture displacement

Complications of Cerclage

• Indirect– Anesthesia risks

– Increased cesarean section rate

– Secondary infertility

– Cervical laceration

– Uterine Rupture

Complications

Procedure related fetal loss Total 2 - 4% Chorioamnionitis 60% Preterm delivery 26%

Newton 1988

Therapeutic cerclage

• Five nonrandomized studies– 3/5 failed to showed any benefit

• Randomized studies– Unselected pop. 113

• CL<25mm or funneling >25%• Cerclage did not prevent PTB

– High risk pop. 35• Cerclage did reduce PTB

Therapeutic cerclage• Meta-analysis by Drakeley “the role

of cerclage in women whose U/S reveals short cervix remains uncertain.“

• ACOG Practice Bulletin No. 48 'management of women who have U/S findings of a short cervix or funneling remains uncertain.'

Drakeley AJ, Roberts D, Alfirevic Z. Cervical cerclage for prevention of preterm delivery: meta-analysis of randomized trials. Obstet Gynecol. 2003;102:621-627. American College of Obstetricians and Gynecologists Practice Bulletin No. 48. Cervical insufficiency. Obstet Gynecol. 2003;102:1091-1099.

© Mosby-Year Book Inc. 2003. All Rights Reserved.

Volume 189(6)             December 2003             pp 1679-1687

Effectiveness of cervical cerclage for a sonographically shortened cervix: A systematic review and meta-analysis

[General Obstetrics and Gynecology: Obstetrics]Belej-Rak, Timea MDa,b,c; Okun, Nan MDb; Windrim, Rory MDb; Ross, Susan PhDa,c,d; Hannah, Mary E MDCMa,c,d

RESULTS: Thirty-five studies were reviewed; 6 studies were eligible and were included in the analysis. There was no statistically significant effect of cerclage on the rates of preterm delivery (<37, <34, <32, and <28 weeks of gestation), preterm labor, neonatal mortality or morbidity, gestational age at delivery, or time to delivery. Birth weight was significantly higher with than without cerclage (P = .004).CONCLUSION: The available evidence does not support cerclage for a sonographically detected short cervix. A randomized controlled trial is needed to determine whether this intervention will reduce adverse neonatal outcomes.

TVU: selection for cerclage• 135 patients were identified for the

study• two groups of patients at risk of

cervical incompetence • Group one had elective cerclage• Group two was followed weekly with

TVU 38% had a Cerclage– One out of 38 (2.6%) patients of the

surveillance group and 18/97 (18.6%) of the elective cerclage group delivered before 30 weeks' gestation (P = 0.034).

Higgins SP. Kornman LH. Bell RJ. Brennecke SP. Cervical surveillance as an alternative to elective cervical cerclage for pregnancy management of suspected cervical incompetence. Australian & New Zealand Journal of Obstetrics & Gynaecology. 44(3):228-32, 2004 Jun. Part

Recommendations • No evidence that screening low risk

patients can be of benefit• At present there is little evidence

placement of a cerclage in patients with shorted or funneled cervix reduces the incidence of PTB or improves neonatal outcomes

• There is some hope that TVU may be useful in determining which patients would benefit from cerclage in patients at risk for cervical insuffiency

Cervical Insufficiency