The February issue of Ultrasound in Obstetrics & Gynecology includes a systematic review on the accuracy of cell-free fetal DNA in detecting chromosomal anomalies in twin pregnancy, an evaluation of the 36-week scan for diagnosis and outcome of abnormal fetal presentation, a MATERA study reporting the use of maternal ophthalmic artery Doppler indices as a predictor for pre-eclampsia and a consensus opinion providing a systematic methodology for ultrasonographic assessment of lymph nodes to assess the extent of gynecological malignancy. This issue also features the newly updated ISUOG Practice Guidelines on the role of ultrasound in twin pregnancy.
Please see below a selection of articles from the February issue of the Journal chosen specially by the UOG team. To view all UOG content, become an ISUOG member today or login and upgrade.
Diagnostic accuracy of cell-free fetal DNA in maternal blood in detecting chromosomal anomalies in twin pregnancy: systematic review and meta-analysis
Twin pregnancies are at increased risk of adverse perinatal outcome in view of the higher prevalence of chromosomal and structural anomalies. As the introduction of cell-free fetal DNA (cfDNA)-based techniques has been transformative for prenatal aneuploidy screening, Della Valle et al. conducted a systematic review and meta-analysis to ascertain the diagnostic accuracy of cfDNA in detecting chromosomal anomalies in twin pregnancy. cfDNA screening was reported to have a sensitivity of 98.8% for detecting trisomy 21 in twin pregnancy and 94.9% sensitivity for trisomy 18, irrespective of chorionicity. Although cfDNA had a sensitivity of 84.6% for trisomy 13 and 100% for other sex-chromosome aneuploidies, these estimations of diagnostic accuracy were limited by the small number of identified affected cases and should be further evaluated in larger studies.
Routine 36-week scan: diagnosis and outcome of abnormal fetal presentation
Undiagnosed non-cephalic presentation in labor is associated with an increased risk of adverse outcome for both the mother and the baby, yet the rate of undiagnosed breech presentation in labor remains relatively high. In a large cohort of 107 875 women, Fitiri et al. assessed the value of the 36-week scan for detection of non-cephalic presentation and the subsequent uptake and success of external cephalic version (ECV). Of the 5.8% pregnancies with breech presentation at the 36-week scan, ECV was attempted in 25.5% of cases and successful in 44.1% of attempts. In 37.7% of pregnancies with breech presentation, there was spontaneous rotation to cephalic presentation. Although these results show that the 36-week scan can reduce the risk of unexpected abnormal presentation in labor, an additional ultrasound scan should be considered in all women when they present in labor to truly avoid unexpected non-cephalic presentation.
Relationship of maternal ophthalmic artery Doppler with uterine artery Doppler, hemodynamic indices and gestational age: prospective MATERA study
Most studies in high-income countries examine models of pre-eclampsia screening at 11–13 weeks, but in low income countries the average gestational age at first presentation is > 20 weeks. Women at 11 + 0 to 23 + 6 weeks’ gestation were recruited in Uganda for inclusion in this MATERA study by Ali et al., to examine the relationship of maternal ophthalmic artery (OA) Doppler indices with uterine artery (UtA) Doppler indices, selected maternal hemodynamic parameters and gestational age. OA-PI and OA-PSV ratio were found to have a weak or no correlation with UtA-PI and maternal hemodynamic parameters, meaning that they can be used as independent predictors for pre-eclampsia and can be measured without adjustment at any time between 11 and 23 weeks' gestation. OA Doppler may therefore be a useful point-of-care clinical test, particularly in low income countries, for predicting pre-eclampsia-related complications and should be validated further in large-scale studies.
Ultrasound assessment of lymph nodes for staging of gynecological cancer: consensus opinion on terminology and examination technique
The lymphatic pathway is an important route of metastasis in gynecological malignancy, thus the ultrasound assessment of lymph nodes is essential in patients with known or suspected gynecological malignancy. Recent advances in ultrasound technology and the use of combined sonographic approaches allow accurate evaluation of lymph-node involvement in advanced gynecological cancer. In this consensus opinion by Fischerova et al., a collaborative group of gynecologists and gynecological oncologists with extensive ultrasound experience present a systematic methodology for ultrasonographic assessment of lymph nodes to assess the extent of gynecological malignancy and describe the anatomical classification and drainage pathways of the lymphatic system as relevant to the gynecological organs. Over 15 videoclips, the authors detail methodology and clinical case examples.
ISUOG Practice Guidelines (updated): role of ultrasound in twin pregnancy
These newly updated ISUOG guidelines by Khalil et al. address the role of ultrasound in the care of uncomplicated twin pregnancies and those complicated by twin–twin transfusion syndrome, selective fetal growth restriction, twin anemia–polycythemia sequence, twin reversed arterial perfusion sequence, conjoined twins and single intrauterine death.