Preterm delivery and ultrasound measurement of cervical length in Gran Canaria, Spain

Prediction of Preterm Labor from the Electrohysterogram Signals Based on Different Gestational Weeks

Timely preterm labor prediction plays an important role for increasing the chance of neonate survival, the mother's mental health, and reducing financial burdens imposed on the family. The objective of this study is to propose a method for the reliable prediction of preterm labor from the electrohysterogram (EHG) signals based on different pregnancy weeks. In this paper, EHG signals recorded from 300 subjects were split into 2 groups: (I) those with preterm and term labor EHG data that were recorded prior to the 26th week of pregnancy (referred to as the PE-TE group), and (II) those with preterm and term labor EHG data that were recorded after the 26th week of pregnancy (referred to as the PL-TL group). After decomposing each EHG signal into four intrinsic mode functions (IMFs) by empirical mode decomposition (EMD), several linear and nonlinear features were extracted. Then, a self-adaptive synthetic over-sampling method was used to balance the feature vector for each group. Finally, a feature selection method was performed and the prominent ones were fed to different classifiers for discriminating between term and preterm labor. For both groups, the AdaBoost classifier achieved the best results with a mean accuracy, sensitivity, specificity, and area under the curve (AUC) of 95%, 92%, 97%, and 0.99 for the PE-TE group and a mean accuracy, sensitivity, specificity, and AUC of 93%, 90%, 94%, and 0.98 for the PL-TL group. The similarity between the obtained results indicates the feasibility of the proposed method for the prediction of preterm labor based on different pregnancy weeks.

Prediction of Preterm Delivery from Unbalanced EHG Database

Objective: The early prediction of preterm labor can significantly minimize premature delivery complications for both the mother and infant. The aim of this research is to propose an automatic algorithm for the prediction of preterm labor using a single electrohysterogram (EHG) signal. Method: The proposed method firstly employs empirical mode decomposition (EMD) to split the EHG signal into two intrinsic mode functions (IMFs), then extracts sample entropy (SampEn), the root mean square (RMS), and the mean Teager–Kaiser energy (MTKE) from each IMF to form the feature vector. Finally, the extracted features are fed to a k-nearest neighbors (kNN), support vector machine (SVM), and decision tree (DT) classifiers to predict whether the recorded EHG signal refers to the preterm case. Main results: The studied database consists of 262 term and 38 preterm delivery pregnancies, each with three EHG channels, recorded for 30 min. The SVM with a polynomial kernel achieved the best result, with an average sensitivity of 99.5%, a specificity of 99.7%, and an accuracy of 99.7%. This was followed by DT, with a mean sensitivity of 100%, a specificity of 98.4%, and an accuracy of 98.7%. Significance: The main superiority of the proposed method over the state-of-the-art algorithms that studied the same database is the use of only a single EHG channel without using either synthetic data generation or feature ranking algorithms.

Sonographic measurement of cervical length as a predictor of preterm delivery: a systematic review

AIM

To evaluate if transvaginal cervical length measurement in the second-trimester scan is an effective screening test for preterm delivery.

METHODS

We performed a search in Medline and, for each selected article, information was extracted regarding the performance of the test in terms of sensitivity, specificity, positive, and negative likelihood ratios, in low-risk, high-risk, and multiple gestations. We also evaluated the performance of the combined test (more than one sonographic marker).

RESULTS

A positive relationship was established between short cervix and preterm delivery in all articles. The majority of studies presented high specificity and positive likelihood ratio, while sensitivity and negative likelihood ratio were variable and globally poor. Better values of accuracy were found in high-risk and multiple gestations and, in all studied subgroups, for preterm delivery at lower gestational ages.

CONCLUSIONS

We conclude that a short cervix is predictive of preterm delivery and can identify women that may benefit from preventive and therapeutic measures, however, a negative result is not always reassuring.

Cervical length vs VOCAL cervical volume for predicting pre-term delivery in asymptomatic women at 20-22 weeks' pregnancy

We conducted a prospective observational study of 306 asymptomatic women at 20-22 weeks of pregnancy to compare 3-dimensional ultrasound measurements of cervical volume with 2-dimensional ultrasound measurements of cervical length to evaluate the performance of cervical volume as a predictor of pre-term delivery, compared with the current standard, cervical length. Participants underwent transvaginal ultrasound measurements of cervical length (mm) and cervical volume (cm(3)). Cervical volume as measured by 3-dimensional ultrasound was found to be a useful tool for predicting pre-term delivery; however, due to the high correlation between cervical length and cervical volume and the lack of differences in the sensitivity, specificity, positive predictive value, negative predictive value and relative risk between the two methods, replacing cervical length measurements with cervical volume calculations does not seem to be justified for this purpose, because of increased difficulty in volume acquisition.

Transvaginal sonographic evaluation of the cervix in asymptomatic singleton pregnancy and management options in short cervix

Preterm delivery (PTD), defined as birth before 37 completed weeks of gestation, is the leading cause of perinatal morbidity and mortality. Evaluation of the cervical morphology and biometry with transvaginal ultrasonography at 16–24 weeks of gestation is a useful tool to predict the risk of preterm birth in low- and high-risk singleton pregnancies. For instance, a sonographic cervical length (CL) > 30 mm and present cervical gland area have a 96-97% negative predictive value for preterm delivery at <37 weeks. Available evidence supports the use of progesterone to women with cervical length ≤25 mm, irrespective of other risk factors. In women with prior spontaneous PTD with asymptomatic cervical shortening (CL ≤ 25 mm), prophylactic cerclage procedure must be performed and weekly to every two weeks follow-up is essential. This article reviews the evidence in support of the clinical introduction of transvaginal sonography for both the prediction and management of spontaneous preterm labour.