Detection rate of the cervical gland area during pregnancy by transvaginal sonography in the assessment of cervical maturation

Assessing the multifaceted cervix: examining cervical gland area at cervical length screening to predict spontaneous preterm birth

BACKGROUND

Biologically active cervical glands provide a mucous barrier while influencing the composition and biomechanical strength of the cervical extracellular matrix. Cervical remodeling during ripening may be reflected as loss of the sonographic cervical gland area. As sonographic cervical length remains suboptimal for universal screening, adjunctive evaluation of other facets of the mid-trimester cervix may impart additional screening benefit.

OBJECTIVE

To sonographically assess the cervical gland area at universal cervical length screening for preterm birth.

STUDY DESIGN

We performed a retrospective cohort study of singletons with transvaginal cervical length screening universally performed during anatomic survey between 18 0/7 and 23 6/7 weeks and subsequent live delivery at a single institution in 2018. Uterine anomalies, cerclage, suboptimal imaging, or medically indicated preterm birth were excluded. Ultrasound images were assessed for cervical length and cervical gland area (with quantitative measurements when present). The primary outcome was spontaneous preterm birth <37 weeks. Absent and present gland groups were compared using χ2, Fisher's exact, T-test, and multivariate logistic regression (adjusting for parity and progesterone use, as well as the gestational age, cervical length, and gland absence at screening ultrasound). Gland measurements were evaluated using the Mann-Whitney-U Test and Spearman's correlation.

RESULTS

Among the cohort of 772 patients, absent and present CGA groups were overall similar. Patients were on average 33 years old, ∼20 weeks gestation at screening ultrasound, and overall, 2.5% had history of prior spontaneous preterm birth. The absent gland group was more likely to have been taking progesterone (17% vs 4%, P=.04). Overall rate of preterm birth was 2.6%. However, the 2.3% of patients with absent cervical gland area were significantly more likely to deliver <37 weeks (aOR 23.9, 95% CI 6.4-89, P<.001). Multivariate logistic regression demonstrated better performance of a cervical length screening model for preterm birth prediction with the addition of qualitative gland evaluation (P<.001). Qualitative gland assessment was reproducible (PABAK 0.89), but quantitative gland measurements did not correlate with preterm birth.

CONCLUSION

Qualitative gland absence at mid-gestation cervical length screening was associated with subsequent spontaneous preterm birth, whereas quantitative gland measurements were not. Multifaceted ultrasound screening may be needed to adequately evaluate the multiple biologic functions of the cervix.

Techniques for detecting cervical remodeling as a predictor for spontaneous preterm birth: current evidence and future research avenues in patients with multiple pregnancies

BACKGROUND

Spontaneous preterm birth occurs more frequently in multiple pregnancies. This syndrome has multiple triggers that result in a unified downstream pathway of cervical remodeling, uterine activity, and progressive cervical dilatation. Whilst the triggers for labor in multiple pregnancy may be different from singletons, the downstream changes will be the same. Identifying patients at risk of preterm birth is a priority as interventions to delay delivery and optimize the fetus can be initiated. Methods for screening for risk of preterm birth which focus on the detection of cervical remodeling may therefore have potential in this population.

METHODS

This review explores the evidence for the predictive utility for preterm birth of several published techniques that assess the physical, biomechanical, and optical properties of the cervix, with a focus on those which have been studied in multiple pregnancies and highlighting targets for future research in this population.

RESULTS

Fifteen techniques are discussed which assess the physical, biomechanical, and optical properties of the cervix in pregnancy. Of these, only three techniques that evaluated the predictive accuracy of a technique in patients with multiple pregnancies were identified: uterocervical angle, cervical consistency index, and cervical elastography. Of these, measurement of the uterocervical angle has the strongest evidence. Several techniques have shown predictive potential in singleton pregnancies, but have not yet been studied in multiple pregnancies, which would be a logical expansion of research.

CONCLUSION

Research on techniques with predictive utility for PTB in patients with multiple pregnancies is limited but should be a research priority. Overall, the theory supports the investigation of cervical remodeling as a predictor of PTB, and there are numerous techniques in development that may have potential in this field.

Effects of prophylactic vaginal progesterone administration on mild cervical shortening (TROPICAL study): a multicenter, double-blind, randomized trial

Vaginal progesterone reduces the preterm birth frequency among high-risk women with a cervical length ≤25 mm at midtrimester. However, the strategy may promote no substantial reduction in overall preterm birth rates, because such high-risk women are only approximately 2% of all pregnant women, which restrict the number of participants. Our purpose was to determine whether prophylactic vaginal progesterone administration can preserve cervical length and reduce preterm birth rates among women with mild cervical shortening.This multicenter, parallel-arm, double-blind, randomized, placebo-controlled trial involved vaginal progesterone administration (200 mg daily from 16 to 33 weeks of gestation) among asymptomatic women with a singleton pregnancy and a sonographic cervical length of 25 to <30 mm between 16 and 23 weeks of gestation. The primary and secondary endpoints were cervical shortening rates at 34 weeks of gestation and preterm birth rates, respectively. The trial was registered at the University Hospital Medical Information Network (UMIN000013518) in Japan.Between April 2014 and March 2018, 119 women were randomly assigned to the progesterone group (n = 59) and the placebo group (n = 60). No significant differences in the frequency of women with a cervical length ≥20 mm at 34 weeks of gestation were observed between both groups. All preterm births occurred after 34 weeks of gestation, except for one patient in the placebo group. The progesterone group had a lower rate of preterm birth before 37 weeks than the placebo group (3.4% vs. 15.0%, respectively; p < .05).Despite having no effect on preserving cervical length, prophylactic vaginal progesterone administration reduced preterm birth frequency among women with mild cervical shortening. Our results are suggesting that women with mild cervical shortening are at risk for late preterm birth and the need for expanding progesterone treatment indications to include not only high-risk but also low-risk populations.

Cervical Assessment for Predicting Preterm Birth-Cervical Length and Beyond

Preterm birth is considered one of the main etiologies of neonatal death, as well as short- and long-term disability worldwide. A number of pathophysiological processes take place in the final unifying factor of cervical modifications that leads to preterm birth. In women at high risk for preterm birth, cervical assessment is commonly used for prediction and further risk stratification. This review outlines the rationale for cervical length screening for preterm birth prediction in different clinical settings within existing and evolving new technologies to assess cervical remodeling.

Evolving cervical imaging technologies to predict preterm birth

Preterm birth, defined as delivery at less than 37 weeks' gestation, increases maternal-fetal morbidity and mortality and places heavy financial and emotional burdens on families and society. Although premature cervical remodeling is a major factor in many preterm deliveries, how and why this occurs is poorly understood. This review describes existing and emerging imaging techniques and their advantages and disadvantages in assessing cervical remodeling. Brightness mode (B-mode) ultrasound is used to measure the cervical length, currently the gold standard for determining risk of preterm birth. Several new B-mode ultrasound techniques are being developed, including measuring attenuation, cervical gland area, and the cervical consistency index. Shear wave speed can differentiate between soft (ripe) and firm (unripe) cervices by measuring the speed of ultrasound through a tissue. Elastography provides qualitative information regarding cervical stiffness by compressing the tissue with the ultrasound probe. Raman spectroscopy uses a fiber optic probe to assess the biochemical composition of the cervix throughout pregnancy. Second harmonic generation microscopy uses light to quantify changes in collagen fiber structure and size during cervical maturation. Finally, photoacoustic endoscopy records light-induced sound to determine optical characteristics of cervical tissue. In the long term, a combination of several imaging approaches, combined with consideration of clinical epidemiologic characteristics, will likely be required to accurately predict preterm birth.

Relationship between detection of the cervical gland area during the late third trimester and necessity for induction of labor to prevent post-term delivery

OBJECTIVES

With the maturation of the cervical canal during pregnancy, the cervical gland area (CGA) as observed on transvaginal ultrasonography is gradually obscured. The aim of this study was to elucidate the significance of CGA in the late third trimester as a determinant of the outcome of labor.

METHODS

We investigated 123 primiparous women with singleton pregnancies at 36-41 weeks' gestation. The women were divided into two groups: a normal delivery group (93 women), which had vaginal delivery without medical intervention, and an induction of labor group (30 women), which required induction of labor after 41 weeks and 0 day. At outpatient prenatal checkups, the Bishop score (BS) was assessed by pelvic examination, and cervical length (CL) and CGA were evaluated by transvaginal ultrasonography. The relationship between each parameter and induction of labor was retrospectively determined and compared.

RESULTS

Time-dependent assessment of each outcome determinant showed that the CGA detection rate was higher and the CL was longer in the induction of labor group from 3 weeks to 1 week before delivery at a significant level (P < 0.05); however, the BS was significantly lower in the induction of labor group only at 1 week before delivery (P < 0.05). When multiple logistic regression analysis of the necessity of induction of labor was conducted using BS, CL, and CGA parameters as explanatory variables at 1 week before delivery, CGA alone was shown to be an independent predictor of induction of labor (OR = 6.1, 95 % CI 2.3-16.2).

CONCLUSION

The present study suggests that in the late third trimester, evaluation of CGA with transvaginal ultrasonography is most useful in predicting the necessity of induction of labor to prevent post-term delivery.

Short cervix syndrome: current knowledge from etiology to the control

BACKGROUND

Preterm delivery is one of the most serious public health problems and is the most important factor relating to neonatal morbidity and mortality. The strategies for preventing it include understanding the risk factors, with specific interventions. Recently, uterine cervix measurements using ultrasonography and vaginal administration of progesterone have gained importance in predicting and secondarily preventing spontaneous preterm delivery.

OBJECTIVE

To describe the short cervix syndrome, including its etiology, diagnosis, and possible therapies.

METHODS

Research in ISI, Pubmed, and Scielo database using the words short cervix, preterm delivery, sludge, cervical funneling, cervical gland area, progesterone, cerclage, and pessary.

RESULTS

We found a lot of articles about this topic, including randomized controlled trials. The etiology is multifactorial, being the diagnosis based in a cervix shortening at 20-24 weeks. The history and measurement of cervix length by transvaginal ultrasound have been shown to be effective to select the high risk pregnancies. The progesterone, cervical cerclage, and cervical pessary showed to be effective to reduce the preterm delivery in pregnant women with short cervix.

CONCLUSION

The successful management of pregnant women presenting a short cervix depends on the understanding that cervical shortening is the final common path for several causes of preterm delivery. The best approach should be individualized to each patient.

Predictive model for spontaneous preterm labor among pregnant women with contractions and intact amniotic membranes

PURPOSE

To determine a predictive model for supporting decisions relating to the prognosis for women presenting with preterm labor and intact membranes.

METHOD

We conducted a prospective observational cohort study on 70 pregnant women at between 22 and 34 weeks of gestation. Transvaginal sonographic evaluation on the cervix was performed once on women who had completed a course of parenteral tocolysis. The sonographic parameters of cervical length measurement and presence of cervical glandular area were obtained. The outcome variable was occurrences of preterm delivery (<35 weeks). Using a univariate logistic regression model, the coefficients of each independent variable were first estimated. To construct the predictive model, multivariate logistic regression containing all the selected variables that might be related to preterm delivery was used as the starting point. Accuracy, sensitivity, specificity and predictive values were used to measure associations of predicted probabilities and to check the ability of the model to predict outcomes. The predictive analyses were based on logistic regression models, with calculation of odds ratios and 95 % confidence intervals.

RESULTS

The incidence of preterm delivery was 32.80 % (23/70). After validation, the predictive model proposed showed accuracy of 87.88 %, sensitivity of 78.26 % and specificity of 93.02 %.

CONCLUSION

The model presented good accuracy with correspondence between predictions and observations, and has the capacity to become a useful tool for management of pregnant women with preterm labor and intact amniotic membranes.

Cervical gland area: a new sonographic marker in predicting preterm delivery

PURPOSE

Preterm delivery is one of the important causes of morbidity and mortality in newborns. Nowadays, a new sonographic marker is suggested for prediction of preterm delivery which is termed "Cervical Gland Area" (CGA). Absence of normal mucosal glands of the cervix can be utilized as a predictor in preterm delivery. This study was performed to evaluate the role of absence of CGA for the prediction of preterm delivery <37 weeks.

METHODS

Trans-vaginal ultrasonography was performed on 600 pregnant women at 16-19 weeks of gestational age. Cervical gland area and cervical length were evaluated. Women with cervical length <25 mm were conducted to cerclage and excluded from the study. Age, number of pregnancies and history of previous preterm deliveries were recorded in questionnaires. The date of delivery was recorded. Statistical analysis was performed by version 18 SPSS and P value <0.05 was significant.

RESULTS

Spontaneous preterm delivery was seen in 6.7% of all women. There was no significant difference in age, cervical length, the number of pregnancies and history of previous preterm deliveries between term pregnancies and preterm cases. CGA was detected in 77.1% of term pregnancies comparing with 55% in preterm group; which was significantly different (P value = 0.002).

CONCLUSIONS

Non detection of CGA at second trimester ultrasonography is a predictor of preterm delivery.

Qualitative glandular cervical score as a potential new sonomorphological parameter in screening for preterm delivery

This study compared diagnostic accuracy of sonographic assessment of cervical length (CL) and qualitative glandular cervical score (QGCS), in the second trimester regarding the prediction of preterm delivery (PTD) in the low-risk population. Cervical length < or = fifth percentile for our population was defined as shortened. The parameters evaluated in QGCS were: cervical mucus area and deepest invasion of cervical glands, and score < or = fifth percentile for our population was defined as low. Shortened CL was found in 6.1% whereas the low QGCS was found in 5.5%. The incidence of PTD < 34 completed wk was 2.1%, and between 34 to 37 wk it was 3%. Low QGCS in comparison with shortened CL had twofold higher likelihood ratio (LR) (23; 95% CI [12 to 43] versus 11; 95% CI [5 to 25]) for PTD < 34 completed wk and fourfold higher LR (12; 95%CI [5 to 28] versus 3; 95% CI [1 to 13]) for PTD between 34 to 37 wk. Low QGCS has the same if not better accuracy in comparison with shortened CL regarding the prediction of PTD in the low-risk population.

Cervical gland area as an ultrasonographic marker for preterm delivery

OBJECTIVE

To assess the association between spontaneous preterm delivery (SPTD) in the general population and the measurement of the cervix length, cervical funneling, and absence of the cervical gland area (CGA).

METHOD

A prospective cohort of 338 women carrying uncomplicated pregnancies was evaluated by transvaginal sonography between 21 and 24 weeks' gestation.

RESULTS

Measurement of cervical length with less than 20 mm and the presence of cervical funneling presented a statistically significant association with SPTD before 35 weeks. The non-detection of CGA demonstrated a strong association with SPTD before 37 weeks' (p < 0.001; OR = 194.5) and before 35 weeks' gestation (p < 0.001; OR = 129.6). The multiple logistic regression analysis suggested the non-detection of CGA as the only variable to reveal statistically significance association with SPTD.

CONCLUSION

The results seem to indicate that the absence of CGA can be a new and important ultrasound marker for SPTD, to be confirmed by future multicenter investigations.

Estudo comparativo entre marcadores ultra-sonográficos morfológicos preditores de parto pré-termo: sinal do afunilamento do colo e ausência do eco glandular endocervical

OBJETIVO: Avaliar o risco de parto pré-termo (PPT) espontâneo na população geral a partir do estudo comparativo dos marcadores ultra-sonográficos morfológicos do colo uterino, como o sinal do afunilamento e a ausência da área glandular endocervical. MATERIAIS E MÉTODOS: Foram arroladas 361 gestantes na população geral, submetidas a exame ultra-sonográfico transvaginal entre a 21ª e 24ª semana, e verificados os resultados perinatais. RESULTADOS: A incidência de PPT espontâneo foi de 5,0%. O sinal do afunilamento foi observado em 4,2% da população estudada e em 22,2% das pacientes que evoluíram para PPT espontâneo. Tal parâmetro mostrou associação significante com PPT (p < 0,001; risco relativo de 6,68). A ausência do eco glandular endocervical (EGE) foi detectada em 2,8% das pacientes estudadas e em 44,4% das pacientes que evoluíram para PPT espontâneo. Este parâmetro demonstrou forte associação com PPT espontâneo (p < 0,001; risco relativo de 28,57). A análise de regressão logística multivariada apontou a ausência do EGE como a única variável morfológica associada ao PPT espontâneo. CONCLUSÃO: A predição do PPT espontâneo a partir de sinais ultra-sonográficos deve ser realizada contemplando marcadores biométricos e morfológicos, entre estes, a ausência do EGE. Este estudo indica uma tendência clara da marcante importância da ausência do EGE como indicador do risco para PPT espontâneo, a ser confirmada futuramente em pesquisas multicêntricas.

Is transvaginal ultrasonography at mid-trimester useful for predicting early spontaneous preterm birth?

Numerous reports have examined the relationship between sonographically determined cervical length and spontaneous preterm birth. Moreover, large screening studies have consistently demonstrated that the shorter the cervical length, the higher the rate of spontaneous preterm delivery. However, the sensitivity and positive predictive value of the cervical length for detecting preterm birth were low. Subsequently, we developed a new sonographic parameter termed "cervical gland area (CGA)". The purpose of this study was to determine whether sonographic cervical findings (shortened cervical length or absence of CGA) at 16 - 19 weeks' gestation could predict spontaneous preterm birth. The absence of CGA as compared to the shortened cervical length showed a higher sensitivity (75.0% vs. 50.0%) and a significantly elevated positive predictive value (54.5% vs. 8.3%) for preterm birth before 32 weeks' gestation. It was concluded that the absence of CGA was a novel and useful sonographic parameter for predicting early spontaneous preterm birth.

Detection of the cervical gland area in threatened preterm labor using transvaginal sonography in the assessment of cervical maturation and the outcome of pregnancy

OBJECTIVES

To detect the cervical gland area in threatened preterm labor, and to determine its detection rate and relationship with cervical maturation and outcome of pregnancy in preterm labor.

METHODS

This was a mixed longitudinal and cross-sectional study involving 615 transvaginal scans performed to detect the cervical gland area and measure cervical length in 101 singleton pregnancies with threatened preterm labor. The patients were treated with intravenous administration of ritodrine chloride for regular uterine contractions at 16-35 weeks of gestation. 260 normal singleton pregnancies served as controls. Simultaneously conventional digital examination was used to assess the cervical maturation index. The detection rates of the cervical gland area, measurements of cervical length by sonography, and assessment of the cervical maturation index by digital examination in threatened preterm labor were compared with those of normal singleton pregnancies. In the threatened labor group, the outcome of pregnancy was assessed according to the sonographic absence or presence of the cervical gland area.

RESULTS

In the normal pregnancy group, the detection rate of the cervical gland area remained practically constant until the 31st week of pregnancy (97%), but substantially decreased thereafter (70.2% in gestational weeks 32-35). In the threatened preterm labor group, the detection rate of the cervical gland area was constantly lower (44.5%) and the cervical maturation index was higher (4.65 score) than in the normal pregnancy group (83.1% and 1.80 score, respectively). The outcome of pregnancy in the threatened preterm labor group was poorer in the subgroup with the absence of a cervical gland area than in the subgroup with the presence of a cervical gland area (duration of pregnancy 257.0 vs. 271.0 days, birth weight 2,597.2 vs. 2,990.0 g, and admission to delivery interval 38.8 vs. 60.8 days). Highly significant correlations were noted among the detection rates of a cervical gland area and cervical length, cervical maturation index, and outcome of pregnancy.

CONCLUSIONS

This study demonstrates for the first time that the sonographic absence of the cervical gland area reflects cervical maturation and could be considered as a predictor of threatened preterm labor and a sign of poor outcome of pregnancy in this condition.