The August issue of Ultrasound in Obstetrics & Gynecology includes a systematic review of studies developing reference charts for fetal biometry of the corpus callosum, a large study investigating the implication of third-trimester screening accuracy for small-for-gestational age and additive value of third-trimester growth-trajectory indicators in predicting severe adverse perinatal outcome in low-risk pregnancies, a study on diagnostic sonographic features and management of intramural pregnancy, and a study proposing markers for first-trimester prediction of ventriculomegaly.
Corpus callosal reference ranges: systematic review of methodology of biometric chart construction and measurements obtained
The corpus callosum (CC) is an important marker of normal brain development, and multiple pathologies of the structure have been described in the literature. Reliable reference ranges for CC biometry are therefore mandatory to improve prenatal diagnostics and facilitate parental counseling. In this systematic review, Corroenne et al. evaluate studies developing reference charts for the fetal CC, demonstrating substantial heterogeneity in both methodology and final biometric values in the existing literature. The authors suggest that the heterogeneity in study methods may explain the discrepancies in the reported charts and emphasize the importance of clearly defined and consistent methodology to allow development of an accurate reference chart and, consequently, detection of CC abnormalities.
Implication of third-trimester screening accuracy for small-for-gestational age and additive value of third-trimester growth-trajectory indicators in predicting severe adverse perinatal outcome in low-risk population: pragmatic secondary analysis of IRIS study
Small-for-gestational age (SGA), commonly defined as estimated fetal weight or abdominal circumference < 10th centile, is often used as a proxy for fetal growth restriction. However, its use is associated with a high rate of false-positive screening findings, which may lead to unnecessary intervention, such as Cesarean delivery and iatrogenic birth. Using data from a Dutch national multicenter randomized trial including 11,820 low-risk pregnant women, van Roekel et al. examine the association of correct or incorrect prenatal prediction of SGA birth weight with perinatal outcome and obstetric intervention. The study shows that false-positive SGA screening findings do not necessarily lead to increased adverse outcome. The study also evaluates the use of third-trimester sonographic growth-trajectory indicators for the identification of abnormal growth and prediction of adverse perinatal outcome, which have recently been proposed as new screening markers in the literature. However, van Roekel et al. demonstrate that the value of third-trimester growth-trajectory measurements is limited in populations remaining at low risk throughout pregnancy.
Imaging in gynecological disease (25): clinical and ultrasound characteristics of intramural pregnancy
Intramural pregnancy is a rare form of ectopic pregnancy, on which there is little published literature regarding the diagnosis, management or natural history. In this large series of patients, Nijjar et al. describe the morphology and key diagnostic features of partial and complete intramural pregnancy on ultrasound, which should facilitate early detection of the condition and lead to better patient care. The findings of the study also suggest that, when intramural pregnancy is diagnosed before 12 weeks’ gestation, it can be managed either conservatively or by surgery, with preservation of reproductive function in most women. The authors stress the importance of development of an international registry for intramural pregnancy to collate data on this rare condition and facilitate the running of prospective, multicenter studies.
First-trimester choroid-plexus-to-lateral-ventricle disproportion and prediction of subsequent ventriculomegaly
Ventriculomegaly is a relatively common fetal abnormality and can be a sign of infection, aneuploidy and structural malformation. Therefore, there is increasing interest in detecting this condition early in pregnancy. In this UOG issue, Prasad et al. demonstrate the utility of first-trimester ratios of choroid plexus to lateral ventricle or head in predicting development of ventriculomegaly at a later gestational age. The best prediction of both mild and severe ventriculomegaly is achieved by the ratios of choroid plexus area to lateral ventricular area and choroid plexus length to lateral ventricular length. Future prospective studies should validate the predictive accuracy of these ultrasound markers as a screening tool for ventriculomegaly.
Coming up next month…
- A systematic review on the outcome of twin–twin transfusion syndrome complicated by selective fetal growth restriction following laser surgery. Preview the Accepted Article.
- A study investigating the effect of women's reproductive history on future in-vitro fertilization outcome. Preview the Accepted Article.
- Two studies focusing on prenatal assessment of the ganglionic eminence using magnetic resonance imaging (Stuempflen et al.) and three-dimensional ultrasound (Contro et al.).