The December issue of Ultrasound in Obstetrics & Gynecology includes an observational cohort study assessing the neurodevelopmental outcomes of uncomplicated monochorionic diamniotic twins, a systematic review evaluating the use of twin vs singleton growth charts for identifying small-for-gestational-age fetuses at risk of adverse neonatal outcomes, a study investigating the performance of non-invasive prenatal testing in vanishing-twin and multiple pregnancies, and a prospective cohort study examining the prevalence of LAM avulsion after forceps-assisted and vacuum-assisted deliveries.
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.
Uncomplicated monochorionic twins: neurodevelopmental insights and implications
Evidence suggests that the unique intrauterine environment of uncomplicated monochorionic diamniotic (MCDA) twins may impact their development; however, the potential long-term neurodevelopmental outcomes of this are poorly understood. In this observational cohort study, Casati et al. sought to assess neurodevelopment in uncomplicated MCDA twins up to 3 years of age and propose recommendations for further research and follow-up protocols. Of the 138 MCDA twins included in the analysis, 40 were diagnosed with mild neurodevelopmental impairment (NDI) and eight with severe NDI. Sixteen infants were diagnosed with behavioral disorders, including eight with autism spectrum disorder (ASD) and eight with emotional dysregulation. Although mean Bayley scores were comparable to those of singletons, rates of mild and severe NDI and ASD in this MCDA twin cohort were higher than in the general population. The authors suggest that a standardized neurodevelopmental follow-up protocol should be implemented for these children, extending at least until school age.
Adverse neonatal outcomes in small-for-gestational age twins identified using twin vs singleton growth charts: systematic review and meta-analysis
Despite a higher risk of growth disorders in twin pregnancies, the use of singleton growth charts may overestimate the prevalence of small-for-gestational age (SGA) twins at risk of adverse neonatal outcomes, with recent evidence suggesting that twin-specific growth charts may offer a more accurate prediction of risk. In this systematic review and meta-analysis, Sorrenti et al. evaluated the use of twin vs singleton growth charts for detecting SGA twins at risk of adverse neonatal outcomes. Analysis found that risk of composite adverse neonatal outcome and most secondary outcomes was significantly higher in SGA fetuses diagnosed using twin charts compared with those diagnosed using singleton charts, whereas these outcomes were similar when comparing SGA fetuses diagnosed using singleton charts with non-SGA fetuses diagnosed using twin charts. Additionally, the risk of composite adverse neonatal outcome was significantly lower when comparing non-SGA fetuses diagnosed using twin vs singleton charts; however, the risk of neonatal complication was similar when comparing SGA vs non-SGA fetuses diagnosed using singleton charts. As a result, it was concluded that twin charts have a lower sensitivity but higher specificity than singleton charts when used in the identification of SGA fetuses.
Performance of non-invasive prenatal testing in vanishing-twin and multiple pregnancies: results of TRIDENT-2 study
Non-invasive prenatal testing (NIPT) has transformed prenatal screening by analyzing total cell-free DNA (cfDNA) in maternal blood to detect chromosomal abnormalities. However, although well-validated in singleton pregnancies, data on the performance of NIPT in vanishing-twin pregnancies remain limited, making interpretation of NIPT results difficult. In this analysis, conducted as part of the TRIDENT-2 study, van Eekhout et al. assessed the performance of NIPT in vanishing-twin and multiple pregnancies. Among 655 vanishing-twin pregnancies, NIPT was indicative of trisomies 21, 18 and 13 in 17, four and eight cases, respectively. In 7/17 (41.2%) of the trisomy 21 cases, the aberration was confirmed in the remaining fetus by cytogenetic follow up; none of the trisomy 18 or 13 cases were confirmed. The sensitivity, specificity and positive predictive value of NIPT for the detection of trisomy 21 was 100% (95% CI, 59.0–100%), 98.5% (95% CI, 97.2–99.3%) and 41.2% (95% CI, 18.4–67.1%), respectively. Therefore, NIPT appears suitable for detecting trisomy 21 in the remaining fetus of a vanishing-twin pregnancy, but findings were inconclusive for other chromosomal abnormalities.
Impact of delivery indication on levator ani muscle avulsion in forceps- and vacuum-assisted deliveries: prospective cohort study
Avulsion of the levator ani muscle (LAM) occurs in approximately 15-52% of vaginal deliveries and is associated strongly with the development of pelvic organ prolapse. In cases of assisted vaginal delivery (AVD), the strongest modifiable risk factor for LAM avulsion is the use of vacuum delivery over forceps delivery, but this has been associated with a higher rate of delivery failure and neonatal trauma. In this prospective cohort study, Grindheim et al. sought to assess the prevalence of LAM avulsion after forceps- and vacuum-assisted deliveries, adjusting for indication of AVD and including spontaneous vaginal deliveries for comparison. Among a cohort of 736 women, forceps delivery was associated with a 2-fold higher risk of LAM avulsion compared with vacuum delivery. In women who underwent AVD for a protracted second stage of labor this risk was 3-fold higher, but no significant difference was observed when AVD was indicated for fetal distress. Given that forceps delivery was also associated with a 51% reduction in odds of neonatal trauma, the authors suggest that this is the safer delivery option in cases of fetal distress.