Implementation of a universal cervical length screening program: identifying factors associated with decline rates

Implementing a Universal Cervical Length Screening Program in a Large Hospital System, it Takes Some Time to Achieve Consistent Results

OBJECTIVE

To describe changes in the acceptance of transvaginal (TV) cervical length (CL) measurements, and in the variance of CL measurements among operators, after implementation of universal TV-CL measurements at 18+0-23+6 weeks/days of gestation.

STUDY DESIGN

Retrospective cohort study Participants/Materials, Setting, Methods This study was performed after universal TV-CL screening was implemented at the University of Texas Health Science Center in Houston, Texas, for all women undergoing an anatomy ultrasound (US) between 18 0/6 and 23 6/7 weeks of gestation. Pregnant women carrying singletons without prior history of preterm delivery who underwent anatomy ultrasound evaluation between September 2017 and March 2020 (30 months) were included. The complete study period was divided in five epochs of six months each. Changes in patient's acceptance for the TV scan, in CL distribution, in the prevalence of short cervix defined as ≤15, ≤20, or ≤25 mm, and in the performance of ultrasound operators across the five epochs were evaluated. For this analysis, success rate was defined as the percentage of TV-CL measurements obtained in relation to the number of second trimester anatomy scans.

RESULTS

A total of 22,207 low risk pregnant women evaluated by 36 trained sonographers were analyzed. Overall, the acceptance for TV-CL measurement was 82.3% (18,289/22,207), increasing from 76.7% in the first epoch to 82.8% (p<0.0001) in the last epoch. The mean CL did not significantly change from 38.6 mm in the first epoch to 38.5 mm in the last epoch (p=0.7); however, the standard deviation decreased from 7.9 mm in the first epoch to 7.04 mm in the last epoch (p=<0.01). The prevalence of a short cervix ≤25 mm was 2.2% (n=399/18,289), ≤20 mm was 1.2% (224/18,289), and ≤15 mm was 0.9% (162/18,289). This prevalence varied only for CL ≤25 mm from 3.02% (88/2,907) in the first epoch to 1.77% (64/3,615) in the last epoch (p=0.0009). There was a variation in CL measurements among operators (mean 3.3 mm). Sonographers with less than one year of experience had a lower success rate for completing TV-CL examinations than more experienced sonographers (80.8% vs. 85.8%; p <0.03). In general 77% (27/35) of operators had a success rate ≥80% for completing TV-SL scans.

LIMITATIONS

Characteristics of individuals who accepted versus those who declined TV-CL were not compared; CL values were not correlated with clinical outcomes.

CONCLUSIONS

During the first six months after implementation of a universal cervical length screening program, there was greater variation in CL measurements, lower acceptance for a TV ultrasound, and a higher number of women diagnosed with a CL ≤25 mm, as compared to subsequent epochs. After the first six months, these metrics improved and remained stable. Most operators improved their performance over time; however, there were a few with a low success rate for TV-CL, and others who systematically over or under estimate CL measurements.

Ultrasonographic Transabdominal Measurement of Uterine Cervical Length for the Prediction of a Midtrimester Short Cervix

OBJECTIVE

This study was aimed to estimate the value of transabdominal (TA) ultrasound measurement of cervical length (CL), as an alternative of transvaginal (TV) ultrasound, for universal screening of short cervix in the midtrimester.

STUDY DESIGN

We conducted a prospective cohort study of nulliparous women with singleton pregnancy at 20 to 24 weeks of gestation. All participants underwent TA ultrasound followed by TV ultrasound with acquisitions of images and videos of the uterine cervix. A second sonographer, blinded to the participants' data and pregnancy outcomes, measured the CL using TA and TV images and videos. Pearson's correlation test and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

A total of 805 participants were recruited, including 780 (97%) where TA CL measurement was feasible. We observed a strong correlation of CL between TA and TV (correlation coefficient: 0.57; p < 0.0001) with a mean TA measurement being 4 mm (95% confidence interval [CI]: -6 to 14 mm) below the mean TV measurement (mean of differences: 5 ± 4 mm). We observed that a TA CL <30 mm was highly predictive of a short cervix defined as a TV CL ≤25 mm (area under the ROC curve: 0.97; 95% CI: 0.95-0.99; p < 0.0001) with a sensitivity of 100% and a false-positive rate of 22%.

CONCLUSION

Universal short cervix screening in nulliparous women could be performed using TA ultrasound, which could allow the avoidance of TV ultrasound in more than three quarter of women. In low-risk population, TV ultrasound could be reserved to women with TA CL <30 mm.

KEY POINTS

· Cervical length (CL) measurement with transabdominal (TA) ultrasound is feasible in most cases and is strongly correlated with CL measured with transvaginal (TV) ultrasound.. · Using a cut-off of 30 mm for TA ultrasound as a first-step screening of short cervix in nulliparous women, three-quarter of TV ultrasound could have been avoided.. · Use of TA CL screening could alleviate some of the logistical challenges of universal TV CL screening..

Preterm Birth Prevention in Appalachian Kentucky: Understanding Barriers and Facilitators Related to Transvaginal Ultrasound Cervical Length Surveillance Among Prenatal Care Providers

Background: Appalachian Kentucky has higher-than-average rates of preterm birth (PTB)-a health disparity associated with increased maternal and fetal/neonatal morbidity and neonatal mortality. Transvaginal ultrasound (TVU) cervical length measurement is the best predictor of PTB risk, but is underutilized in Appalachia. This study explores prenatal care providers' TVU-related knowledge and practices, and identifies barriers and facilitators, which impact the adoption of this evidence-based technology. Materials and Methods: This study recruited providers from three Appalachian Kentucky health care sites. Prenatal care providers took part in semistructured interviews and completed brief survey scales. Questions focused on PTB knowledge, TVU-related barriers, and suggestions for clinician and/or patient-focused interventions. Transcripts were coded using a multistage process based in grounded theory. Descriptive statistics were calculated. Results: Eleven physicians, one nurse practitioner, one physician assistant, and one midwife completed interviews. Average participant age was 44 years with 17 years in practice; 43% of providers were female. Practitioners described the sociodemographic characteristics, health behaviors (e.g., smoking, opioid abuse), and comorbid conditions (e.g., obesity, hypertension, and diabetes) endemic in Appalachia that heightened their patients' PTB risk. TVU use was reported as important by all respondents, but not all were satisfied with their level of training. The most commonly identified barriers to TVU were patient access to transportation and social support. Participants stressed a need for changing community perceptions regarding consequences of PTB. Conclusions: Providers identified multiple TVU-related barriers and facilitators. These data will inform the design of a multifaceted dissemination and implementation strategy targeting PTB prevention in Appalachia.

Decrease in the incidence of threatened preterm labor after implementation of transvaginal ultrasound cervical length universal screening

BACKGROUND

It is unknown if universal second-trimester transvaginal ultrasound (TVU) cervical length (CL) screening in asymptomatic women with singleton gestations and no prior spontaneous preterm birth (SPTB) affects the incidence of symptoms of preterm labor (PTL) later in pregnancy.

OBJECTIVE

To evaluate the incidence of threatened PTL before and after the implementation of universal second trimester TVU CL screening.

STUDY DESIGN

This was a retrospective cohort study of all consecutive singleton gestations without prior SPTB presenting to obstetric triage for threatened PTL between 23 0/7 and 33 6/7 week in 2011 (1 January-31 December), and in 2014 (1 January-31 December) at Thomas Jefferson University Hospital (TJU) (Philadelphia, PA). These 2 years were chosen as a new protocol for universal TVU CL screening was started on 1 January 2012. This protocol involved one measurement of TVU CL in all singleton gestations without a prior SPTB at 18 0/7 - 23 6/7 week, the time of the "anatomy" scan. Women with prior SPTB were excluded from this study. The primary outcome included the incidence of threatened PTL, defined as the number of women with singleton gestations without prior SPTB who presented with threatened PTL to our labor and delivery (L&D) triage unit annually, divided by the total number of annual deliveries of women with singleton gestation without prior SPTB. Secondary outcomes were the incidence of PTL, defined as the number of women with singleton gestations without prior SPTB admitted for PTL annually divided by the total number of annual deliveries of women with singleton gestation and without prior SPTB; and length of stay in the hospital. We aimed to compare primary and secondary outcome in the "2011" versus the "2014" group.

RESULTS

In 2011, there were a total of 1745 deliveries at TJU, of which 1550 (88.8%) were singletons without prior SPTB. In 2014, there were a total of 1924 deliveries at TJU, 1751 (91.0%) were singletons without prior SPTB who were offered universal TVU CL screening. One hundred and seventy-two women with singletons without prior SPTB presented in L&D triage unit in 2011; and 118 women with singletons without prior SPTB presented in L&D triage unit in 2014. There were significant decreases in the incidence of threatened PTL from 11.1% (172/1550) in 2011 to 6.7% (118/1751) in 2014 (p < .001), as well as in the rate of admission for PTL from 2.3% (35/1550) to 1.4% (24/1751), respectively (p = .04). Length of stay was not significantly different between the two groups.

CONCLUSION

The introduction of a universal TVU CL screening program in women with singleton gestations without a history of SPTB is associated with a reduction in the frequency of threatened PTL and admission for PTL. Key Message The introduction of a second trimester universal transvaginal ultrasound (TVU) cervical length (CL) screening program in women without a history of spontaneous preterm birth (SPTB) is associated with a reduction in the incidence of threatened preterm labor (PTL) and admission for PTL.