The December issue of Ultrasound in Obstetrics & Gynecology includes a prospective study investigating the utility of a machine-learning-based model for predicting pre-eclampsia, two studies on anal sphincter trauma and a study comparing fetal and neonatal sonographic parameters of brain ventricular size. Also in the issue are the first systematic review and meta-analysis to report on the incidence of congenital heart disease in fetuses with premature atrial contractions and an accompanying Editorial by Julene Carvalho proposing a systematic management protocol for cases with rhythm irregularities.

Please see below a selection of articles from the December issue of the Journal chosen specially by the UOG team. To view all UOG content, become an ISUOG member today or login and upgrade.

Comparison of fetal and neonatal sonographic measurements of ventricular size in second- and third-trimester fetuses with or without ventriculomegaly

Different sonographic indices are used for prenatal and neonatal assessment of brain ventricular size. The atrial width (AW) is the most recognized parameter in the fetus, while the ventricular index, fronto-occipital horn ratio, anterior horn width and thalamo-occipital distance are the most common variables used for neonatal assessment. In their new study, Gerbino et al. evaluate the agreement between prenatal and neonatal indices in fetuses with and without ventriculomegaly. Their findings indicate a strong association between the four indices developed for neonatal assessment and fetal AW when the AW measurement indicates severe fetal ventriculomegaly (areas under the receiver-operating-characteristics curves (AUC) > 0.95) and a weaker association for ventriculomegaly of any degree (AUC range, 0.77–0.87). These findings may allow monitoring of the severity of ventriculomegaly in a continuum, from the first intrauterine evidence into the neonatal period.

Machine-learning-based prediction of pre-eclampsia using first-trimester maternal characteristics and biomarkers

Machine-learning methods are increasingly researched and applied in the field of diagnostics and medical screening. In their new study, Ansbacher-Feldman et al. propose a non-linear machine-learning-based approach based on a combination of maternal risk factors and non-normalized first-trimester biomarkers for pre-eclampsia screening, which allows prediction of the condition with high accuracy. The method has a similar performance to logistic regression and does not require population-based normalization, which should facilitate wider implementation of first-trimester pre-eclampsia screening. The study also demonstrates the importance of taking into account race when screening for pre-eclampsia, as its exclusion from the presented model significantly reduces the prediction accuracy.

Comparison of diagnostic criteria for significant anal sphincter defects between endoanal and transperineal ultrasound

Endoanal ultrasound (EAUS) and transperineal ultrasound (TPUS) are both used to evaluate the anal sphincter after obstetric anal sphincter injury, and the former technique is considered to be the gold standard. A significant anal sphincter defect on TPUS is currently defined based on a cut-off angle of 30°, which is derived from the EAUS criteria. The study by Okeahialam et al. evaluates the agreement between the two modalities. Their findings indicate that agreement between 3D EAUS and 4D TPUS is excellent in diagnosing the presence of anal sphincter defect but is poor-to-moderate in measuring the defect angle. Further research is required to determine the cut-off angle for a significant defect on TPUS, while a cut-off angle of 30° should not be used for the diagnosis on TPUS based on the results of this study.

Validation of new ultrasound algorithm for estimating prevalence of anal sphincter trauma in a urogynecological population

The Gillor algorithm, which takes into account scarring and anatomical distortion in addition to defects on exoanal ultrasound, has been proposed to allow retrospective grading of anal sphincter trauma. Dietz et al. estimate the prevalence of different grades of major perineal trauma in a large urogynecological population of 721 patients and assess whether the Gillor algorithm is superior to the standard residual-defect method in terms of quantifying sphincter trauma on imaging and predicting anal incontinence. Their findings suggest moderate agreement between the residual-defect method and the Gillor algorithm and a weak association of both tools with anal incontinence. Thus, the Gillor algorithm for sonographic tear grading may be useful in the follow-up of women who suffered an anal sphincter tear during childbirth, but it is not superior to the residual-defect method in predicting anal incontinence.

Implications of fetal premature atrial contractions: systematic review

Fetal premature atrial contractions (PAC) are usually considered to be a benign condition of minor clinical significance, which resolves spontaneously during the course of pregnancy or the neonatal period. Nevertheless, there is some evidence indicating that PAC may be a sign of congenital heart defect (CHD) and adverse fetal outcome. The systematic review and meta-analysis of 19 studies on the topic by Bet et al. suggests that the incidence of CHD is increased in fetuses with PAC compared with the general population (2.8% vs 0.6%, respectively). High-risk PAC cases with other reasons for referral (maternal medical condition, use of medication or unfavorable obstetric/family history) have a pooled incidence of CHD of 7.2%, compared with 0.9% in the low-risk PAC population. Complications such as supraventricular tachyarrhythmia, cardiac failure and intrauterine fetal demise occur in less than 2% of PAC cases. These findings support the utility of an advanced ultrasound examination to diagnose PAC and exclude CHD. Despite the rarity of complications, heart-rate monitoring is advisable to enable early detection of supraventricular tachyarrhythmia and prevention of cardiac failure and fetal death.

UOG video abstract

Coming up next month…

  • Newly updated ISUOG Practice Guidelines on performance of first-trimester ultrasound scan.
  • A systematic review and meta-analysis investigating perinatal outcome following blastocyst vs cleavage-stage embryo transfer. Preview the Accepted Article.
  • A follow-up study of a multicenter trial reporting on neurodevelopmental outcome after antenatal therapy for fetal supraventricular tachyarrhythmia. Preview the Accepted Article.
  • Latest research on cytomegalovirus infection in pregnancy, including:
    • A study on the efficacy of valacyclovir for prevention of maternal–fetal viral transmission. Preview the Accepted Article.
    • A multicenter study on the role of fetal brain MRI in detecting anomalies in cases with congenital cytomegalovirus. Preview the Accepted Article.