Routine Cervical Length Screening Research Articles

Current Practice of Maternal-Fetal Medicine Specialists Regarding the Prevention and Management of Preterm Birth in Twin Gestations.

To investigate the current practices of maternal-fetal medicine (MFM) specialists regarding the prevention and management of preterm birth (PTB) in twin pregnancies. This was a cross-sectional study of Canadian MFM specialists. Participants responded to an anonymous survey regarding the prevention and management of PTB in twins, including lifestyle and gestational weight gain recommendations, cervical length screening, PTB prevention, and labour and delivery practices. Of 137 MFM specialists surveyed, 95 (69%) responded. Most MFM specialists recommend against activity restriction (77.9%), avoidance of sexual activity (96.7%), routine progesterone (97.8%), routine prophylactic cerclage (98.9%), and routine administration of antenatal corticosteroids (95.6%). There were considerable inconsistencies with respect to gestational weight gain management. Despite lack of support by guidelines, most MFM specialists reported using routine cervical length screening (97.8%) and progesterone for short cervix (92.3%). Over half (52.7%) of MFM specialists recommend cervical cerclage when the cervix is <15mm. In cases of PTB, most MFM specialists recommend vaginal delivery when twins are in vertex presentation (63%-75%). MFM specialists are less likely to recommend vaginal delivery when twin B is non-vertex (35%-41%). There is a considerable variation among MFM specialists regarding the prevention and management of PTB in twins, and the practice of many MFM specialists differs from that recommended by professional societies' guidelines. These findings underscore the necessity for high-quality studies and up-to-date recommendations.

423: The association between 3D cervical volume and spontaneous preterm birth

Cervical length measurement is used to predict spontaneous preterm birth (sPTB), but it only evaluates the cervix in 2 dimensions and has a low sensitivity. Advances in 3D ultrasound allow imaging of the cervical volume. We sought to investigate the relationship between cervical volume and sPTB. We conducted a prospective cohort study of singleton gestations between 16 0/7-23 6/7 weeks from February 2016 to March 2017. The cervical length was measured in 2D according to the CLEAR protocol, and a 3D volume of the cervix was obtained during routine cervical length screening. The cervical volume was later measured by two separate examiners using VOCAL software with 30 degree rotations of the cervix. The primary outcome was sPTB < 37 wks. Multivariable regression was performed to account for potential confounding by maternal age, race, ethnicity, body mass index (BMI), history of sPTB and parity. A total of 345 subjects underwent 3D imaging of the cervix. 2 minutes of post-processing time were required for cervical volume measurement. The median cervical volume was 40 cm3 (range 14.4 -108.9 cm3). Cervical volume measurements by the separate examiners were highly correlated (correlation coefficient 0.86, p<0.001). The rate of sPTB <37 wks in this cohort was 7.1%. There was a positive correlation between cervical volume measurement and gestational age at delivery (p=0.047). On average, subjects with sPTB had a significantly lower cervical volume compared to those without sPTB (36.4 cm3 vs 43.1 cm3, p=0.04). Lower cervical volume was associated with nulliparity (p=0.02), history of sPTB (p<0.001), lower BMI (p=0.02) but there were no differences in cervical volume by maternal age, race or ethnicity. The primary outcome remained significant after adjustment for parity, history of sPTB and BMI (p<0.001). This prospective study found that 3D cervical volume is associated with gestational age at delivery and sPTB. Cervical volume measurement was reproducible across examiners. Further prospective studies are needed to determine if this measurement adds value to routine cervical length screening.

Comparison of Risk Factors and Neonatal Outcomes Among Women With a Spontaneous Versus Iatrogenic Preterm Birth [24O

INTRODUCTION: While spontaneous preterm birth (sPTB) has been trending down, iatrogenic preterm birth (iPTB) has been trending up. The purpose of this study is to examine the difference in risk factors and neonatal outcomes among women with a sPTB vs iPTB to identify areas for intervention. METHODS: Retrospective cohort study from 1/2012-12/2014 of singleton pregnancies without a history of prior sPTB undergoing routine cervical length screening between 18 0/7-23 6/7 weeks. Women were included if they delivered less than 37 weeks. RESULTS: Of 3678 women screened, 200 women (5.4%) had a PTB; 114 (57%) sPTB and 86 (43%) iPTB. Women with sPTB were on average younger than those with iPTB (27.3 ±6.2 vs 29.5 ±6.4, p=0.019). Women with iPTB were more likely to have a BMI of at least 30 (39% vs 23%, p=0.021), have a hypertensive disorder of pregnancy (74% vs 9%, p &lt; 0.001), and have fetal growth restriction (14% vs 0%, p &lt; 0.001) than women with sPTB. Women with a sPTB delivered earlier, with a mean gestational age of 32.7±4.9 vs 34.1±2.7 weeks (p=0.015), and an increased incidence of delivery less than 28 weeks (17% vs 4%, p=0.003). However, infants born from an iPTB were more likely to require intensive care admission (71% vs 54%, p=0.016). The incidence of neonatal morbidity was similar. CONCLUSION: Although sPTB tends to result in an earlier gestational age of delivery, iPTB is a more significant source of neonatal intensive care admission. Maternal obesity and hypertensive disorders are major modifiable risk factors for iPTB.

The role of routine cervical length screening in selected high- and low-risk women for preterm birth prevention

Preterm birth remains a major cause of neonatal death and short and long-term disability in the US and across the world. The majority of preterm births are spontaneous and cervical length screening is one tool that can be utilized to identify women at increased risk who may be candidates for preventive interventions. The purpose of this document is to review the indications and rationale for CL screening to prevent preterm birth in various clinical scenarios. The Society for Maternal-Fetal Medicine recommends (1) routine transvaginal cervical length screening for women with singleton pregnancy and history of prior spontaneous preterm birth (grade 1A); (2) routine transvaginal cervical length screening not be performed for women with cervical cerclage, multiple gestation, preterm premature rupture of membranes, or placenta previa (grade 2B); (3) practitioners who decide to implement universal cervical length screening follow strict guidelines (grade 2B); (4) sonographers and/or practitioners receive specific training in the acquisition and interpretation of cervical imaging during pregnancy (grade 2B).

The role of routine cervical length screening in selected high- and low-risk women for preterm birth prevention

The role of routine cervical length screening in selected high- and low-risk women for preterm birth prevention

Routine cervical length screening to prevent PTB: Answers to frequently asked questions about when to perform CL measurement

Routine cervical length screening to prevent PTB: Answers to frequently asked questions about when to perform CL measurement

Association between second-trimester cervical length and cesarean delivery in multiparas.

The purpose of this study was to determine whether there is an association between second-trimester cervical length and cesarean delivery in women with a prior vaginal delivery. We conducted a retrospective cohort study of multiparous women with singleton gestations who underwent routine cervical length screening between 18 and 24 weeks' gestation and labored after 34 weeks. Cervical lengths were divided into quartiles, and the frequency of cesarean delivery was compared across the groups. Indications for cesarean delivery were also compared. A multivariable logistic regression was performed with cervical length as a categorical and a continuous variable to adjust for potential confounders. Of the 2260 multiparas who met inclusion criteria, 63 (2.8%) underwent a cesarean delivery. We observed no association between the second-trimester cervical length quartile and the frequency of cesarean delivery (2.1%, 3.5%, 2.3%, and 3.1%, respectively; P = .434). Further analysis using cervical length as a continuous variable and controlling for potential confounding variables did not change this result (adjusted odds ratio, 1.08; 95% confidence interval, 0.80-1.46). The second-trimester cervical length quartile in multiparas is not associated with an increased frequency of cesarean delivery. This finding differs from studies of nulliparas.

Association Between Second-Trimester Cervical Length and Primary Cesarean Delivery

To evaluate whether an increased ultrasonographic cervical length in the second trimester is associated with an increased frequency of cesarean delivery. This is a retrospective cohort study of nulliparous women with a singleton pregnancy who underwent routine cervical length screening between 16 and 24 weeks of gestation and labored after 34 weeks of gestation at a single tertiary care hospital. Women were grouped by cervical length quartile, and the association between cervical length quartile and cesarean delivery was determined in both univariable and multivariable analyses. For every additional centimeter of cervical length, the odds of cesarean delivery increased by 20.3%. Similarly, the frequency of cesarean delivery increased with increasing second-trimester cervical length quartiles (17.4%, 22.3%, 21.8%, 27.7%; P<.001). This association persisted in multivariable analyses that included gestational age at delivery and induction of labor. This increased risk of cesarean delivery was primarily the result of women with arrest disorders in the first stage of labor (P<.001). Increased second-trimester cervical length quartile is associated with an increased frequency of primary cesarean delivery in nulliparous women. : II.

Universal cervical‐length screening to prevent preterm birth: a cost‐effectiveness analysis

To determine whether routine measurement of second-trimester transvaginal cervical length by ultrasound in low-risk singleton pregnancies is a cost-effective strategy. We developed a decision analysis model to compare the cost-effectiveness of two strategies for identifying pregnancies at risk for preterm birth: (1) no routine cervical length screening and (2) a single routine transvaginal cervical length measurement at 18-24 weeks' gestation. In our model, women identified as being at increased risk (cervical length < 1.5 cm) for preterm birth would be offered daily vaginal progesterone supplementation. We assumed that vaginal progesterone reduces preterm birth at < 34 weeks' gestation by 45%. We also assumed that a decreased cervical length could result in additional costs (ultrasound scans, inpatient admission) without significantly improved neonatal outcomes. The main outcome measure was incremental cost-effectiveness ratio. Our model predicts that routine cervical-length screening is a dominant strategy when compared to routine care. For every 100,000 women screened, $12,119,947 can be potentially saved (in 2010 US dollars) and 423.9 quality-adjusted life-years could be gained. Additionally, we estimate that 22 cases of neonatal death or long-term neurologic deficits could be prevented per 100,000 women screened. Screening remained cost-effective but was no longer the dominant strategy when cervical-length ultrasound measurement costs exceeded $187 or when vaginal progesterone reduced delivery risk at < 34 weeks by less than 20%. In low-risk pregnancies, universal transvaginal cervical length ultrasound screening appears to be a cost-effective strategy under a wide range of clinical circumstances (varied preterm birth rates, predictive values of a shortened cervix and costs).

460: Universal cervical length screening to prevent preterm birth: a cost-effectiveness analysis

Objective To determine whether routine measurement of second-trimester transvaginal cervical length by ultrasound in low-risk singleton pregnancies is a costeffective strategy. Methods We developed a decision analysis model to compare the cost-effectiveness of two strategies for identifying pregnancies at risk for preterm birth: (1) no routine cervical length screening and (2) a single routine transvaginal cervical length measurement at 18–24 weeks’ gestation. In our model, women identified as being at increased risk (cervical length < 1.5 cm) for preterm birth would be offered daily vaginal progesterone supplementation. We assumed that vaginal progesterone reduces preterm birth at < 34 weeks’ gestation by 45%. We also assumed that a decreased cervical length could result in additional costs (ultrasound scans, inpatient admission) without significantly improved neonatal outcomes. The main outcome measure was incremental cost-effectiveness ratio. Results Our model predicts that routine cervical-length screening is a dominant strategy when compared to routine care. For every 100 000 women screened, $12 119 947 can be potentially saved (in 2010 US dollars) and 423.9 quality-adjusted life-years could be gained. Additionally, we estimate that 22 cases of neonatal death or long-term neurologic deficits could be prevented per 100 000 women screened. Screening remained costeffective but was no longer the dominant strategy when cervical-length ultrasound measurement costs exceeded $187 or when vaginal progesterone reduced delivery risk at < 34 weeks by less than 20%.