Mid-trimester Cervical Length Research Articles

Changing Indications for Cervical Cerclage Following the Introduction of Routine Ultrasound Surveillance of Cervical Length for Prediction and Prevention of Preterm Birth.

Preterm birth (PTB) is associated with significant neonatal mortality and morbidity. Universal measurement of cervical length has been proposed as a screening tool to direct intervention to prevent PTB. To assess the impact of the introduction of sonographic mid-trimester cervical length screening on the use of cervical cerclage and PTB. A retrospective cohort study reviewed two groups of women who underwent cervical cerclage before and after the introduction of universal sonographic cervical length screening. Demographics and outcomes were compared using Student's t test, Fisher's Exact test and Kaplan-Meier analysis. Following introduction of universal cervical length screening, the overall rate of cerclage increased from 2.5/1000 births to 6.0/1000 births (p < 0.01). There was a reduction in the proportion of sutures placed purely based on maternal history (50.0% to 30.4%; p < 0.001), while the proportion of sutures placed following ultrasound assessment increased in both high- (21.7 to 36.6%) and low-risk (11.7% to 30.4%) women (p < 0.001). The overall rate of PTB <37weeks in women has a cerclage was 25.7% and was highest in women undergoing rescue cerclage (64.3%; p < 0.01). There was no difference in the rate of PTB between high- and low-risk women undergoing history- or ultrasound-indicated cerclage. Mean pregnancy length was most prolonged in low-risk women undergoing ultrasound-indicated cerclage, extending gestation from 33.9 to 38.3weeks (p < 0.01). Universal cervical length screening results in an increase in the use of cerclage, specifically on the basis of the ultrasound findings. Women who were at low risk but then underwent ultrasound-indicated cerclage experienced most prolongation of pregnancy. Women who were at high risk but had a suture on the basis of ultrasound findings-indicated cerclage represent an alternative method of management with no significant difference in the gestational age of delivery.

Predictive value of short cervix in early third trimester for preterm birth in women with normal mid-trimester cervical length

BackgroundShort cervical length in the mid-trimester is a powerful predictor of preterm birth (PTB). However, clinical significance of cervical length in the third trimester for predicting PTB has not been established yet. ObjectiveTo examine the predictive role of a shortened cervix in the third trimester for PTB in women who had a normal cervical length in the second trimester Study designThis retrospective cohort study included women who underwent cervical length measured at least once in both the second trimester (16+0 weeks to 27+6weeks) and the early third trimester (28+0 weeks to 33+6 weeks). Women with short cervical length in the second trimester, those with multiple pregnancies, those who underwent cerclage operation, and those who had iatrogenic PTB were excluded. The study population was divided into two groups based on cervical length in the third trimester: a short cervix (≤25 mm) group and a control group (>25 mm). Rates of PTB (<37 weeks) were compared between two groups. Predictive performances of cervical length in the third trimester for PTB were assessed. ResultsWomen with a short cervical length at 28+0 to 33+6 weeks accounted for 12.6% (n=717) of the total study population (n=5682). PTB rate was 9.5% in the short cervix group, which was significantly higher than that (3.2%) in the control group (P<.001). The adjusted odds ratio for short cervical length on PTB was 2.73 (95% CI: 1.96–3.79). A short cervix in the third trimester had a sensitivity of 30.1%, a specificity of 88.1%, a positive predictive value of 9.5%, and a negative predictive value (NPV) of 96.8% in predicting PTB. The addition of third-trimester cervical length to the predictive model significantly increased the area under the curve from 0.64 (95% CI: 0.60–0.68) to 0.67 (95% CI: 0.63–0.71) (P=.002), demonstrating improved predictive performance. ConclusionApproximately 13% of women with normal cervical length in the mid-trimester had a short cervical length after 28 weeks, which increased the risk of PTB. The high specificity and NPV of third-trimester cervical length measurements underscore their critical utility in identifying women at low risk for preterm delivery.

The Effect of Maternal Parity on Preterm Birth Risk in Women with Short Mid-Trimester Cervical Length: A Retrospective Cohort Study.

Objectives: To evaluate the effect of maternal parity on the association between mid-trimester cervical length and preterm birth to elucidate the potential intricacies of this relationship. Methods: A retrospective cohort study using Electronic Medical Records (EMR) data. The study population included pregnant women with a singleton fetus and a short mid-trimester cervical length, recorded in the EMR system at a large health maintenance organization. Women were categorized by parity in the current pregnancy, and a statistical analysis was conducted to examine the relationship between parity and premature delivery. Results: Data were collected from 1144 records of cervical length measurements of 738 pregnancies obtained from the HMO database. The study population consisted of 259 nulliparous women (35.1%), 451 multiparous women (61.1%), and 28 grand multiparous women (3.8%). The results from the multivariate analysis of the primary outcome showed that nulliparity was significantly associated with an increased risk of premature delivery, with a risk of 1.557 for nulliparous women compared to parous women. Conclusions: In this study, a statistically significant association was found between nulliparity and preterm birth among women with a short mid-trimester cervical length. Nulliparous women were found to have a higher risk of preterm birth in the current pregnancy compared to parous women. Further research is needed to understand the underlying mechanisms and to develop targeted interventions to reduce the risk of premature birth in this population. These findings highlight the need to consider nulliparity as a potential risk factor in the management of pregnancies with a shortened cervix.

Comparison of Short Cervical Lengths in Singleton and Twin Pregnancies

Introduction: Multifetal gestations are six times more likely to give birth preterm and 13 times more likely to give birth before 32 weeks gestation than women with singleton gestation (Martin et al, 2014-2018). Abnormal cervical shortening measured with transvaginal ultrasonography has been associated with an increased risk of preterm birth (Iams et al, 1996). In singleton pregnancies, midtrimester cervical length of less than 2.5 cm measured between 16-24 weeks has been associated with an increased risk of preterm birth in a variety of screened populations (Crane, JM., Hutchens, D., 2008). In twin pregnancies, a shortened cervix in the second trimester is more common than in singleton pregnancies and can be a predictor of early preterm birth (Yang et al, 2000). Current guidelines from ACOG, state that the data is insufficient to recommend for or against routine endovaginal ultrasound screening of cervical length in twin pregnancy. Our aim was to determine if twin gestations have shorter cervical lengths than singletons at the time of midtrimester anatomy scan, and to investigate the correlation of cervical length with the likelihood of spontaneous preterm birth. Methods: Retrospective chart review between January 2016-January 2022 identified patients with cervical shortening (&lt;2.5 cm) at the time of mid-trimester anatomical ultrasound exam. Exams were performed at the Maternal Fetal Medicine Department at Promedica Toledo Hospital between 16 and 24 weeks’ gestation. Cervical lengths and delivery data were collected and analyzed. Results: 122 patients met inclusion criteria, with 95(78%) singleton pregnancies, and 27(22%) twin gestations. Singleton gestations had an average short cervical length of 1.8 ± 0.6cm, whereas twin gestations had an average short cervical length of 1.29 ± 0.55cm (p&lt;0.0001). Twin gestations were more likely than singleton gestations to have a very short cervical length &lt;1.5cm (OR=6.75, 95% CI 2.59-17.58, p =0.0001). Average gestational age of delivery for singleton gestations identified with a short cervix was 35w6d ± 4w4d, whereas the average age at delivery for twin gestations was 31w6d ± 5w6d (p=0.0002). Discussion: Our results are consistent with previous reports that cervical shortening is more common in twin pregnancies than singleton pregnancies. Our results suggest that twins are more likely to have a very short cervical length identified in between 16-24 weeks. In addition, twin gestations with abnormal cervical shortening deliver at earlier gestational ages in comparison to singleton gestations with abnormal cervical shortening. Obtaining transvaginal cervical lengths at 16-24 weeks gestation allows for earlier identification of shortened cervical length. Ongoing research may identify interventions which are consistently effective in preterm birth prevention in twin gestation.

SMFM Consult Series #70: Management of short cervix in individuals without a history of spontaneous preterm birth

The majority of deliveries before 34 weeks of gestation occur in individuals with no prior history of preterm birth. Mid-trimester cervical length assessment by transvaginal ultrasound is one of the best clinical predictors of spontaneous preterm birth. This Consult provides guidance for the diagnosis and management of short cervix in an individual without a history of preterm birth. The following are Society for Maternal-Fetal Medicine recommendations: (1) we recommend that all cervical length measurements used to guide therapeutic recommendations be performed using a transvaginal approach and in accordance with standardized procedures as described by organizations such as the Perinatal Quality Foundation or the Fetal Medicine Foundation (GRADE 1C); (2) we recommend using a midtrimester cervical length of ≤ 25 mm to diagnose short cervix in individuals with a singleton gestation and no prior history of spontaneous preterm birth (GRADE 1C); (3) we recommend that asymptomatic individuals with a singleton gestation and a transvaginal cervical length of ≤ 20 mm diagnosed prior to 24 weeks of gestation be prescribed vaginal progesterone to reduce the risk of preterm birth (GRADE 1A); (4) we recommend that treatment with vaginal progesterone be considered at a cervical length of 21 to 25 mm based on shared decision-making (GRADE 1B); (5) we recommend that 17-OHPC, including compounded formulations, not be prescribed for the treatment of a short cervix (GRADE 1B); (6) in individuals without a history of preterm birth who have a sonographic short cervix (10-25 mm), we recommend against cerclage placement in the absence of cervical dilation (GRADE 1B); (7) we recommend that cervical pessary not be placed for the prevention of preterm birth in individuals with a singleton gestation and a short cervix (GRADE 1B); (8) we recommend against routine use of progesterone, pessary, or cerclage for treatment of cervical shortening in twin gestations outside the context of a clinical trial (GRADE 1B).

Cervical length screening among low-risk women; relationship of body mass index on cervical length and risk of preterm birth

BackgroundPreterm birth (PTB) contributes to nearly 11% of all deliveries in the world. The majority of spontaneous preterm birth (sPTB) remains unexplained. Risk factors include abnormal body mass index (BMI), short cervical length, comorbidities and many more. However, there is limited study on the association between body mass index, cervical length and preterm birth in Malaysia among low-risk women. Hence, we aim to examine the relationship between body mass index, cervical length and the risk of spontaneous preterm birth.MethodIn this prospective cohort study, pregnant women between 16 and 24 weeks who fulfilled the criteria were recruited. Women with history of preterm birth were excluded. Demographic and clinical data (age, BMI, ethnicity, education level and parity) were obtained. Cervical length was measured using transvaginal scan. Patients were then followed up till delivery to determine their delivery gestation and outcome of delivery.ResultsOut of 153 women who participated in this study, 146 women had cervical length of more than 30 mm, six had cervical length between 25 mm and 30 mm and one had cervical length of 24 mm. There were nine (9) cases of sPTB, with all of them being late preterm with normal midtrimester cervical length. Almost half of them (44%) were overweight/obese. A significant association was found between age, cervical length, and parity compared to BMI. Nevertheless, no significant association was seen between the BMI and risk of sPTB.ConclusionThis study demonstrates a higher BMI is associated with longer cervical length, but it is not necessarily protective against sPTB. Hence, we concluded there is a limited role in cervical length screening among low-risk women regardless of their BMI in predicting sPTB.

530 Comparison of the normal mid-trimester cervical length between singleton and twin gestations

530 Comparison of the normal mid-trimester cervical length between singleton and twin gestations

The effectiveness of cervical cerclage in twin pregnancies with a mid-trimester short cervix: A retrospective cohort study

ObjectiveTo analyze the effectiveness of cerclage in twin pregnancies with a short cervix. Study designRetrospective cohort study performed in two University Institutions in Valencia (Spain) with two different protocols for the management of asymptomatic dichorionic diamniotic twin pregnancies with mid-trimester cervical length ≤ 25 mm: treatment with indomethacin, antibiotics and cerclage (cerclage group) (N = 43) versus expectant management (control group) (N = 37). ResultsThe initial cervical length was similar in both groups but detection of a short cervix was performed earlier in the cerclage group (21.6 vs 24.1 weeks, p < 0.001). Women with cerclage had a greater pregnancy latency (12.5 vs. 7.7 weeks, p < 0.001); higher gestational age at delivery (34.1 vs. 31.8 weeks, p < 0.04); less spontaneous preterm birth (SPB) < 28 weeks (11.6 % vs 37.8 %, p < 0.009); higher birthweight (2145 vs 1733 g, p < 0.001); lower birthweight < 1500 g (12.5 % vs 40.0 %, p < 0.001); less admissions to the neonatal intensive care unit (NICU) (24.1 % vs 43.3 %, p < 0.03); shorter stay at NICU (25.6 vs 49.4 days, p < 0.02); lower respiratory distress requiring mechanical ventilation (14.9 % vs 36.5 %, p < 0.02); fewer patent ductus arteriosus (8.9 % vs 26.9 %, p < 0.008); and lower composite adverse neonatal outcome (26.6 % vs. 44.8 %, p < 0.03). Cerclage and gestational age at diagnosis were the only independent predictors of SPB < 32 and < 28 weeks by multivariate analysis. The cumulative data in the literature show promising beneficial effects of cerclage. ConclusionOur data suggest that cerclage in asymptomatic twin pregnancies with a short cervix may reduce the earliest SPB and may improve neonatal outcome.

Validating staging criteria for sonographic and physical examination for cervical changes at

BackgroundPreterm birth represents a significant clinical challenge, and the ability to predict it effectively is a priority in obstetrics. The cervix undergoes specific changes during pregnancy, and staging these changes may offer a valuable predictive model for preterm birth, particularly in women with a mid-trimester short cervical length. ObjectiveThe study aims to validate a proposed staging model for asymptomatic women with mid-trimester short cervical length and evaluate its potential in predicting preterm birth. The integration of cervical examination and inspection with cervical length measurement was a novel approach to be assessed. Study DesignA multi-center retrospective cohort study included 925 pregnant women with a singleton fetus and a mid-trimester cervical length measurement of 25 mm or less. Cervical conditions were assessed using ultrasound, speculum, and physical examination, and classified according to five cervical staging to correlate with the likelihood of preterm birth. Statistical analyses included Kaplan-Meier Survival Analysis to illustrate the time-to-event characteristics across the five stages, and density plot evaluation to visualize the distribution of gestational ages within the stages. ResultsThe staging model included five stages based on cervical length, appearance, and dilatation. Among the 925 participants, 649 were classified as Stage 1, 245 as Stage 2, 18 as Stage 3, 10 as Stage 4, and 3 as Stage 5. The observed rates of preterm birth before 37 weeks for individuals classified in Stages 1, 2, 3, 4, and 5 were 22.3%, 26.5%, 44.4%, 60%, and 66.7%, respectively (p = 0.005). The overall observed rates of preterm birth before 28, 32, 34, and 37 weeks’ gestation were 5.5%, 9.9%, 12.2%, and 24.1%, respectively (p = 0.005). ConclusionsThis study validates the proposed staging criteria as an effective predictor of preterm birth due to cervical insufficiency. The results demonstrate a significant increase in the preterm birth rate with advancing stage classifications, indicating that the staging effectively stratifies women based on their risk of preterm birth, and highlighting the potential utility for targeted interventions. Implementing these staging criteria can potentially improve the counseling and management of pregnant women at risk for preterm birth.

Mid-trimester cervical length and prediction of vaginal birth after cesarean delivery in Chinese parturients: A retrospective study

BackgroundA successful trial of labor after cesarean (TOLAC) is linked with the best maternal/neonatal outcomes and is more cost-effective than elective repeat cesarean section (ERCS). Predictive models of vaginal birth after cesarean (VBAC) have been established worldwide to improve the success rate of TOLAC. ObjectiveTo validate a VBAC prediction model (the updated Grobman's predictive model without ethnicity) and identify whether mid-trimester cervical lengths (MCL) improve the prediction of VBAC among Chinese women undergoing a TOLAC. MethodsIn this retrospective cohort study, the inclusion criteria were a previous history of cesarean delivery (CD) as well as a singleton gestation in the vertex position with routine CL measurements between 20 and 24 weeks and the experience of a TOLAC. MCL as well as identifiable characteristics in early prenatal care that have been used in updated Grobman's predictive model (maternal age, height, pre-pregnancy weight, vaginal delivery history, VBAC history, arrest disorder in previous CD, and treated chronic hypertension) were obtained from the medical records. Associations of maternal characteristics and MCL with VBAC were evaluated using multivariate logistic regression. Two multivariable regression models with and without MCL as one of the risk factors were established and their predictive accuracy for VBAC was critically compared based on receiver-operating characteristic (ROC) curves. ResultsThis study involved 409 women, among which, 347 (84.8%) achieved a VBAC. The mean MCL was significantly shorter in women who had a successful VBAC than in those who required an intrapartum CD (4.16±0.49 cm vs. 4.35±0.46 cm, P=0.007). Multivariable logistic regression revealed that a longer MCL (cm) was significantly related to a lower success rate of TOLAC [adjusted odds ratio (aOR), 0.48; 95% confidence interval (CI), 0.26−0.88]. The areas under the ROCs of Grobman's model with and without MCL as one of the risk factors were 0.785 (95% CI, 0.725−0.844) and 0.774 (95% CI, 0.710−0.837), respectively, but not significantly different (Z = −0.968, P = 0.333). ConclusionsWe first evaluated the efficiency of the updated Grobman's model (without race and ethnicity) in the Chinese population. The area under the curve is relatively high, indicating that the model can be used efficiently in China. The shorter MCL was associated with a greater chance of VBAC and MCL was the independent factor from the factors of Grobman's model. However, the predictive capacity of the modified model by adding MCL as one of the risk factors did not improve significantly.

Maternal and obstetrical factors associated with short cervical length at midtrimester in women with no history of preterm delivery

Aim To evaluate associations between maternal characteristics and a short cervix in patients without history of preterm delivery, and to determine if these characteristics can predict the presence of a short cervix. Materials and methods This is a retrospective cohort study that included 18,592 women with singleton pregnancies without history of previous preterm deliveries who underwent universal transvaginal cervical length (TVCL) screening between 18 + 0 and 23 + 6 weeks/days of gestation. A short cervix was defined as a cervical length (CL) ≤25 mm, ≤20 mm, and ≤15 mm. Associations between maternal age, weight, height, body mass index (BMI), previous term deliveries, and history of previous miscarriages, with a short cervix were evaluated using logistic regression models. Results The prevalence of a short cervix in our population was: CL ≤25 mm, 2.2% (n = 403); CL ≤20 mm, 1.2% (n = 224); and CL ≤15 mm, 0.9% (n = 161). Women with BMI >30 and/or previous abortions constituted 45.5% of the total population (8463/18,582). Significant associations with short cervix were observed for women with BMI ≥30, and for women with at least one previous abortion (p < .001). Parous women had a significantly lower association with a short cervix than nulliparous women (p < .001). Maternal age or height were not associated with a short cervix. Prediction of short cervix based on presence of any of the following: BMI ≥ 30 or previous abortions showed sensitivities of 55.8% (≤25 mm), 61.6% (≤20 mm), and 63.4% (≤15 mm) with similar specificity (50.1–54.6%) and likelihood ratio positive (1.2–1.5); and prediction based on BMI ≥ 30 and previous abortions showed sensitivities of 11.1% (≤25 mm), 14.7% (≤20 mm), and 16.7% (≤15 mm) with specificity 93%. Conclusions Among low risk women for spontaneous preterm delivery, those with a BMI ≥30 and/or previous miscarriages had a significantly increased risk for a short cervix at 18 + 0 and 23 + 6 weeks/days of gestation. Despite these significant associations, screening by maternal risk factors in a low risk population of pregnant women should not be an alternative to mid-trimester universal CL measurement.

Is mid-trimester cervical length screening effective for reduction of threatened preterm labor?

ObjectiveTo assess the incidence of threatened preterm labor and preterm labor admissions and treatment of women with singleton gestations and no prior preterm birth before and after implementation of the universal mid-trimester transvaginal ultrasound cervical length screening. Materials and methodsA retrospective cohort study included of singleton gestations without a history of preterm birth presenting with threatened preterm labor between 24 0/7 and 36 6/7 gestational week in two study periods: before and after the implementation of the universal cervical length screening. Women with cervical length <25 mm were considered being at high risk for preterm birth and were prescribed a treatment with vaginal progesterone daily. The primary outcome was the incidence of threatened preterm labor. Secondary outcomes were the incidence of preterm labor. ResultsWe have found a significant increase in the incidence of threatened preterm labor from 6.42% (410/6378) in 2011 to 11.61% (483/4158) in 2018 (p < 0.0001). Gestational age at triage consult was lower in than in 2011, although the rate of admission for threatened preterm labor was similar in both periods. There was a significant decrease in the incidence of preterm delivery <37 weeks from 25.60% in 2011 to 15.94% in 2018 (p < 0.0004). Although there was a reduction in preterm delivery ≤34 weeks, this reduction was not significant. ConclusionThe universal mid-trimester cervical length screening in asymptomatic women is not associated with a reduction in the frequency of threatened preterm labor or the admission rate for preterm labor, but reduces the rate of preterm births.

Short cervix and preterm birth in the top end.

Reducing rates of preterm birth (PTB) remains a significant challenge. The Northern Territory (NT) records some of the highest rates of PTB in the country, especially in First Nations women. In 2014, a Western Australian (WA) preterm birth prevention initiative involved the implementation of seven key initiatives. One of these was routine mid-trimester cervical length measurement. The initiative successfully reduced PTB rates following its first year of implementation. This was the first successful reduction in PTB, including the earlier gestational ages, across a population. To assess the uptake of routine cervical length measurement in the Top End of the NT after the success of the WA PTB prevention initiative and assess if treatment of a short cervix improved PTB rates. A retrospective cohort study of all women who received antenatal care and delivered their baby at the NT's only tertiary hospital was performed. Mid-trimester ultrasound scan data were collected from two separate time windows, before and after the implementation of the WA intervention. Treatments and gestational age at birth were recorded. Adoption of routine screening of cervical length measurement at mid-trimester ultrasound in the NT was successful, increasing from 4 to 88%. Detection rates of short cervix doubled. However, there was no difference to PTB rates despite targeted management. PTB remains a significant challenge in the NT, especially for First Nations women who are found to have a short cervix more commonly than non-Indigenous women in the Top End.

The Relationship between Mid-trimester Cervical Length and Pre-term Delivery and Maternal Characteristics

The Relationship between Mid-trimester Cervical Length and Pre-term Delivery and Maternal Characteristics

Cervical funneling is more predictive of preterm birth than cervical length alone in nulliparous women

Universal mid-trimester cervical length (CL) screening is a well-accepted practice for detection of women at risk of spontaneous preterm birth (sPTB). In those identified with a short cervix, progesterone supplementation is recommended. However, current guidelines do not consider a short cervix an indication for cerclage without a history of sPTB as it has poor sensitivity for this outcome. It is currently unclear if other sonographic features such as cervical funneling can identify a higher sPTB risk in a population without prior sPTB. This was a secondary analysis of the nuMom2b study, which enrolled a large prospective observational cohort of pregnant nulliparous women. Patients were stratified based on CL < 25mm or ≥25mm and presence or absence of funneling at the time of cervical length evaluation between 16-22 weeks’ gestation. Logistic regression was used to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for sPTB adjusting for confounders. A Kaplan-Meier survival analysis was performed between groups and gestational age at delivery. 7,648 nulliparous women were included in the analysis. There were 169 (2.2%) women identified with a short CL < 25 mm and 52 (0.7%) with funneling. While a short CL had a higher risk of PTB (Table 1), a short CL was detected in only 24 (7.1%) of women who ultimately had a sPTB. The presence of a funnel was independently associated with higher odds of sPTB (OR 3.4, CI 1.9-8.1) when compared to CL < 25mm (OR 2.7, CI 1.7-4.4). On survival analysis, a short CL with funneling showed the lowest mean gestational age at delivery (Figure 2, p< .001). In a nulliparous population without prior sPTB, transvaginal cervical length alone is a poor predictor of preterm delivery, but presence of funneling significantly increases risk. This may identify a population of women who would benefit from cerclage.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

VAGINAL PROGESTERONE IN RISK REDUCTION OF PRETERM BIRTH IN WOMEN WITH SHORT CERVIX IN MID TRIMESTER OF PREGNANCY

Background: Preterm labour is a major health challenge in obstetrics. Many risk factors being identified, the most common one is short cervical length, can be diagnosed by transvaginal ultrasound scan after 13 weeks of pregnancy. Vaginal progesterone is the most bioavailable form of progesterone that have effect on uterine and cervix. Progesterone is found to inhibit the production of proinflammatory cytokines and prostaglandins within the uterus and to inhibit myometrial contractility Aim:To evaluate the efficacy of vaginal progesterone administration for preventing preterm birth and decrease perinatal morbidity and mortality in asymptomatic women with a singleton gestation and a mid-trimester sonographic cervical length (CL) ≤ 25 mm. Materials And Methods:This is a prospective study of asymptomatic women with a singleton pregnancy and a sonographic short cervix (&lt;25mm) at 19 + 0 to 23 + 6 weeks of gestation. Women were allocated randomly to receive vaginal progesterone or placebo daily starting from 19 + 0 to 23 + 6 weeks until 36 + 6 weeks, rupture of membranes or delivery, whichever occurred first. Randomization sequence was stratified by centre and history of a previous preterm birth. The primary endpoint was preterm birth before 33 weeks of gestation. Analysis was by intention to treat. Results:Out of 100 patients for whom study was done, 20 lost to followup and remaining divided into two groups: 40 Singleton pregnant women with CL&lt;25mm between 19 + 0 to 23 + 6 weeks of gestation with no sign and symptoms were given daily vaginal progesterone for up to 36 + 6 weeks, rupture of membranes or delivery, whichever occurred first. The dose is 200 mg once daily and a group of 40 women with cervical length of &lt;25 mm between 19 + 0 to 23 + 6 weeks of pregnancy were given no treatment, Maximum distribution belongs to age of 19-24 years followed by 30-34 years. Most of women in this study have no history of preterm labour. In those who received vaginal progesterone 5 women had history of previous preterm labour and five women in no treatment group. It was found that there was statistically significant reduction in preterm labour in women with short cervix &lt;2.5cm with 200mg vaginal progesterone. Conclusions:This updated systematic review and meta-analysis reaffirms that vaginal progesterone reduces the risk of preterm birth and neonatal morbidity and mortality in women with a singleton gestation and a mid-trimester CL ≤ 25 mm, without any deleterious effects on neurodevelopmental outcome. Clinicians should continue to perform universal transvaginal CL screening at 19 + 0 to 23 + 6 weeks of gestation in women with a singleton gestation and to offer vaginal progesterone to those with a CL ≤ 25 mm.

Midtrimester cervical elastography in pregnant women with a history of loop electrosurgical excision procedure (LEEP)

We aimed to compare cervical elastographic parameters based on a previous loop electrosurgical excision procedure (LEEP) and to determine whether they can predict preterm delivery in pregnant women with a history of LEEP. This multicenter prospective case–control study included 71 singleton pregnant women at 14–24 weeks of gestation with a history of LEEP and 1:2 gestational age-matched controls. We performed cervical elastography using E-cervix and compared maternal characteristics, delivery outcomes, cervical length (CL), and elastographic parameters between the two groups. The median mid-trimester CL was significantly shorter in the LEEP group. Most elastographic parameters, including internal os (IOS), external os (EOS), elasticity contrast index (ECI), and hardness ratio (HR), were significantly different in the two groups. In the LEEP group, the sPTD group compared to the term delivery (TD) group showed a higher rate of previous sPTD (50% vs. 1.7%, p < 0.001), higher IOS and ECI (IOS: 0.28 [0.12–0.37] vs. 0.19 [0.10–0.37], p = 0.029; ECI: 3.89 [1.79–4.86] vs. 2.73 [1.48–5.43], p = 0.019), and lower HR (59.97 [43.88–92.43] vs. 79.06 [36.87–95.40], p = 0.028), but there was no significant difference in CL (2.92 [2.16–3.76] vs. 3.13 [1.50–3.16], p = 0.247). In conclusion, we demonstrated that a history of LEEP was associated with a change in cervical strain measured in mid-trimester as well as with CL shortening. We also showed that cervical elastography can be useful in predicting sPTD in pregnant women with previous LEEP.

Evaluation of midtrimester cervical length thresholds for the prediction of spontaneous preterm birth

IntroductionTo estimate the optimal midtrimester cervical length (CL) threshold for the prediction of spontaneous preterm birth (sPTB) in asymptomatic pregnant women. Material and methodsThis is a prospective observational cohort study including asymptomatic women with singleton pregnancies who underwent CL measurement by transabdominal and/or transvaginal ultrasound between 19°/7 and 216/7 weeks of gestation. All CL ≤30 mm from transabdominal ultrasound were confirmed by transvaginal ultrasound. Primary outcomes were sPTB <35 and <37 weeks. ResultsOut of 3,449 participants, 28 (0.8%) had a sPTB before 35 weeks and 99 (2.9%) had a sPTB before 37 weeks. Receiver operating characteristics (ROC) curves suggest that a cut-off of 30 mm was the optimal CL to predict sPTB before 35 weeks (sensitivity: 43%; specificity: 97%) and sPTB before 37 weeks (sensitivity: 21%; specificity: 97%). While a CL <25 mm was an important risk factor for sPTB before 35 weeks (relative risk: 31; 95% confidence interval: 13–73), women with a CL between 25 and 30 mm were also at greater risk (relative risk: 12; 95% confidence interval: 4 – 35) compared to women with CL ≥30 mm. DiscussionA midtrimester CL <30 mm should be considered to identify women at high-risk of sPTB.

Impact of past obstetric history and cervical excision on preterm birth rate.

To determine the impact on preterm birth (PTB) of a history of large loop excision of the transformation zone (LLETZ)-alone compared with a history of previous preterm birth-alone (PPTB) or a history of both (LLETZ+PPTB). Secondary analyses were performed to evaluate the impact of antenatal interventions, depth of cervical excision, and patient risk factors on PTB rate in each cohort. A retrospective observational cohort study of women referred to a tertiary Antenatal Prematurity Prevention Clinic with a history of LLETZ, PPTB, or LLETZ+PPTB. Information was collated from routinely collected clinical data on patient demographics, previous obstetric history, LLETZ dimensions, antenatal investigations/interventions, and gestation at delivery. A total of 1231 women with singleton pregnancies were included, 543 with history of LLETZ-alone, 607 with a history of PPTB-alone and 81 with a history of LLETZ+PPTB. PTB rates were 8.8% in the LLETZ-alone group, which mirrored the PTB rate in the local background obstetric population (8.9%) compared with 28.7% in the PPTB-alone and 37.0% in the LLETZ+PPTB cohorts. PTB rates were higher in LLETZ cohorts treated with antenatal intervention (cervical cerclage or progesterone pessary) and there was no evidence of an effect of intervention on risk of PTB in post-excision patients with identified shortened mid-trimester cervical length. Logistic regression modeling identified PPTB as a strong predictor of recurrent PTB. Excision depth was correlated with gestation at delivery in the LLETZ-alone group (r=-0.183, p<0.01) although this only reached statistical significance at depths of 20mm or more (odds ratio [OR] 3.40, 95% CI 1.04-1.11, p=0.04). Depth of excision was not correlated with delivery gestation in the LLETZ+PPTB group (r=-0.031, p=0.82). PPTB has a greater impact on subsequent PTB risk compared with depth of cervical excisional treatment. The value and nature of antenatal interventions should be investigated in the post-excision population.

Revisions to mid-pregnancy cervical length reference range for preterm birth screening among singleton pregnancies in Taiwan – 10 years’ experiences

ObjectiveOur study aimed to build a normal reference range for routine mid-pregnancy cervical length screening for preterm birth (PTB) based on a large cross-section of Taiwanese singleton pregnancies. Based on our reference range findings, we aim to develop a Z-score and centile calculator. Materials and methodsWe performed a retrospective analysis of the routine mid-trimester cervical length measurement in low-risk singleton pregnancies (without known abnormal growth or karyotype, congenital malformation, history of preterm birth due to preterm premature rupture of the membranes, or history of cervical cerclage treatment). From November 2008 to June 2018, the cervical lengths of 51,644 Taiwanese low-risk pregnant women were measured by experienced sonographers via transvaginal ultrasound during second trimester fetal anatomical screening at 20–24 weeks of gestation. Kolmogorov–Smirnov test was used to assess the normality of the distribution. Cole's lambda, mu, sigma (LMS) method was applied to build mid-pregnancy cervical length reference range and calculate Z-scores. Cut-off values of 2.5, 2.0 and 1.5 cm were used to evaluate the number of pregnancies considered high-risk for PTB. ResultsKolmogorov–Smirnov test showed that the cervical length measurements did not follow a normal distribution (<0.001). Reference range constructed by LMS method was presented in our study. Mean cervical length was 3.82 cm (SD = 0.62 cm). Overall, less than 0.3% of women had a cervical length shorter than 1.5 cm. ConclusionWe are providing an open access calculator for z-score and centile calculation for use in clinical practice for assessing how CL measurement compares in normally developing singleton pregnancies. Further investigation is needed to determine if Z-scores can better assess risk for PTB compared to fixed cut-offs. Since Z-scores are used to assess large deviations from normal development, they may be a useful tool for risk assessment and can be the basis for future standardized screening protocol in Taiwan.