Use of a Cervicometer in Assessing Cervical Length and Risk of

Use of a Cervicometer in
Assessing Cervical Length and
Risk of Preterm Birth
A Multicenter Study
Jason K. Baxter,
MD, MSCP
Thomas Jefferson University, Philadelphia, PA
C. David Adair, MD, Michael J. Paidas, MD,
Asad U. Sheikh, MD, Matthew K. Hoffman, MD, MPH,
and Michael G. Ross, MD, MPH
INTRODUCTION: Although current obstetric practice
guidelines suggest cervical length assessment in singletons
for preterm birth risk, transvaginal ultrasonography has
availability limitations. CerviLenz is a disposable device to
measure vaginal cervical length. We sought to determine
the threshold CerviLenz measurement with optimal specificity and sensitivity for diagnosis of short cervix by
transvaginal ultrasonography and compare the abilities of
CerviLenz and transvaginal ultrasonography to predict
preterm birth.
METHODS: Women with singleton pregnancies and no
cervical anomalies or surgery or premature labor were
consented, enrolled, and followed to delivery. Transvaginal
ultrasonography and CerviLenz cervical length measurements were obtained by independent examiners at 17–23
weeks of gestation. A central reader certified sonographers
and reviewed all transvaginal ultrasound scans.
RESULTS: Based on 358 patients, receiver operator curves
indicated optimal CerviLenz threshold of 30 mm to detect
short cervix (transvaginal ultrasound cervical length at or
below 25 mm). CerviLenz detected a short cervix with
a negative predictive value (NPV) of 100%, sensitivity of
100%, and specificity of 46% (Table 1). Preterm birth
before 37 weeks of gestation occurred in 25 (7%) patients.
Area under the curve analyses for preterm birth before 28,
32, or 35 weeks of gestation revealed similar results for
CerviLenz and transvaginal ultrasonography. For preterm
birth before 37 weeks of gestation, CerviLenz had greater
sensitivity (60%, transvaginal ultrasonography 16%) and
transvaginal ultrasonography had higher specificity (97%,
CerviLenz 44%).
CONCLUSIONS: At a 30-mm threshold, CerviLenz has
high NPV, high sensitivity, and moderate specificity to
detect a short cervical length in the second trimester.
Table 1. CerviLenz Cervical Length at 30-mm
Threshold Relative to Transvaginal
Ultrasonography at 25-mm Threshold
(17–23 Weeks of Gestation [n5358])
Transvaginal ultrasound 25 mm or less
13 (3.6%)
Sensitivity (95% CI)
100.0% (75.3–100.0)
Specificity (95% CI)
45.5% (40.2–50.9)
NPV (95% CI)
100.0% (97.7–100.0)
P
,.001
CI, confidence interval; NPV, negative predictive value.
VOL. 123, NO. 5 (SUPPLEMENT), MAY 2014
CerviLenz is similar to transvaginal ultrasonography in
prediction of preterm birth at 28–37 weeks of gestation.
Based on high NPV, CerviLenz is clinically useful in identifying women not at risk for preterm birth, having potential to substantially reduce the need for transvaginal
ultrasound screening in singletons.
Financial Disclosure: Jason K. Baxter, MD, MSCP—This author has a relevant financial relationship with the following commercial interest: Research
Grant: Cervilenz. C. David Adair, MD—This author has a relevant financial
relationship with the following commercial interest: Chairman and Founder:
Glenveigh Medical. Michael J. Paidas, MD—This author has a relevant financial relationship with the following commercial interest: Research Grant:
Cervilenz. Asad U. Sheikh, MD, and Matthew K. Hoffman, MD, MPH—
These authors have no conflicts of interest to disclose relative to the contents of
this presentation. Michael G. Ross, MD, MPH—This author has relevant
financial relationships with the following commercial interests: Medical Director: Cervilenz; Stock Ownership: Cervilenz; Medical Director: Sense4Baby.
Perimortem Cesarean Delivery
Injury-Free Survival as a Function of
Arrest-to-Delivery Interval Time
Michael D. Benson,
MD
Feinberg School of Medicine, Northwestern University, Deerfield, IL
Alexander Padovano,
and Ying Zhou, PhD
BSc,
Ghada Bourjeily,
MD,
INTRODUCTION: Currently, cardiopulmonary resuscitation of pregnant women in the third trimester is informed
by the “4-Minute Rule.” Cesarean delivery is begun at 4 minutes after the arrest if the mother is not responding to
resuscitation so that the fetus can be delivered in the
next minute, yet this guideline has never had much empirical support.
METHODS: All English language case reports of perimortem cesarean deliveries through the present (N553) were
abstracted into an Excel spreadsheet for statistical analysis
to examine the relationship of time intervals to key outcomes.
RESULTS: For mothers, the mean time from arrest to birth
for injury-free survivors was 9.44 minutes, whereas for
those who died, it was 24.7 minutes (P5.016). For newborns, the mean for injury-free survivors was 10.08 minutes, whereas for those who died, it was 20.29 minutes
(P5.035). Mean skin incision to birth interval was 3.94 minutes (standard deviation 5.95). No discontinuity in injuryfree survival rates was noted with a 5-minute arrest to
delivery interval. Injury-free survival for both mothers
and newborns decreased in a roughly linear fashion as
the time from arrest to delivery increased.
CONCLUSION: With a direct relationship of increasing
injury and mortality for both mother and neonate with
increasing arrest to delivery intervals, cesarean delivery
should be an integral part of cardiopulmonary resuscitation
in the third trimester. These data do not support a 4-minute
delay to evaluate resuscitation nor a 1-minute incision to
delivery time.
Financial Disclosure: Michael D. Benson, MD, Alexander Padovano,
BSc, Ghada Bourjeily, MD, and Ying Zhou, PhD—These authors have no
conflicts of interest to disclose relative to the contents of this presentation.
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