The January issue of Ultrasound in Obstetrics & Gynecology includes a systematic review and meta-analysis investigating perinatal outcome following blastocyst- vs cleavage-stage embryo transfer, two multicenter studies on cytomegalovirus infection in pregnancy, and a follow-up study of a multicenter trial, which is the first to report on the long-term mortality and morbidity of cases receiving transplacental treatment for fetal supraventricular tachyarrhythmia. This issue also includes the newly updated ISUOG Practice Guideline on the performance of first-trimester ultrasound scan.

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

Congenital anomaly and perinatal outcome following blastocyst- vs cleavage-stage embryo transfer: systematic review and network meta-analysis

To date, there has been limited evidence to inform the choice between blastocyst- vs cleavage-stage embryo transfer (ET) for assisted reproduction. In a systematic review and meta-analysis of 33 studies, Siristatidis et al. compare the outcome of the two ET techniques and stratify their analysis further according to the use of embryo cryopreservation. On pairwise meta-analysis, the authors demonstrate no difference between blastocyst- vs cleavage-stage ET in terms of perinatal outcome, apart from an increased probability of a male neonate following blastocyst ET. However, the authors find significant differences when comparing frozen-blastocyst, fresh-blastocyst, frozen-cleavage and fresh-cleavage ET strategies on network meta-analysis. As such, frozen-blastocyst ET appears to be associated with a reduction in the risk of low birth weight when compared with both fresh ET modalities, while fresh-cleavage ET may reduce the risk of perinatal death compared with frozen-blastocyst ET. Moreover, the analysis demonstrates a lower risk for preterm delivery of multiple pregnancies following fresh-cleavage transfer compared with all other modalities. The authors emphasize the need for high-quality studies with separate data on fresh and frozen ET and consistent reporting in future research to provide confirmatory evidence regarding the advantages and disadvantages of each ET type.

Neurodevelopmental outcome after antenatal therapy for fetal supraventricular tachyarrhythmia: 3-year follow-up of multicenter trial

Although the efficacy of transplacental treatment for fetal supraventricular tachyarrhythmia is supported by multiple studies, the long-term neurodevelopmental outcome following antenatal antiarrhythmic treatment has not been studied. Miyoshi et al. report the results of a 3-year follow-up study of a multicenter trial that evaluated the efficacy and safety of a transplacental treatment for fetal supraventricular tachycardia and atrial flutter. The authors report a 2% rate of mortality and a 4.7% rate of neurodevelopmental delay at 36 months of corrected age, with the latter occurring only in infants with severe congenital abnormalities. Neurodevelopmental impairment at 36 months of corrected age was diagnosed in 9% of infants and appears to be associated with the presence of fetal hydrops with subcutaneous edema. Finally, tachyarrhythmia was present in 32% cases in the neonatal period, with the rate decreasing to 4.5% at 36 months of corrected age. The study provides further evidence supporting the efficacy of transplacental treatment and indicates a low risk of mortality and adverse neurodevelopmental outcome in treated cases. Nevertheless, the risk for long-term neurological morbidity after antenatal therapy should be considered, especially in cases with associated abnormalities.

New data on efficacy of valacyclovir in secondary prevention of maternal–fetal transmission of cytomegalovirus

Congenital cytomegalovirus (CMV) infection is an important cause of congenital neurological deficits and is the leading non-genetic cause of hearing loss. In their multicenter study, Egloff et al. evaluate the efficacy of valacyclovir in reducing the risk of maternal–fetal CMV transmission in patients with maternal primary CMV infection by comparing the rate of congenital CMV infection at birth between women receiving 8 g of valacyclovir daily and untreated controls. Their findings suggest that valacyclovir treatment reduces the risk of fetal infection, with a trend towards reduction in the rate of transmission even in the second trimester of pregnancy. The efficacy of treatment appears to be greater in cases with positive maternal viremia at treatment initiation. These findings highlight the benefits of valacyclovir treatment for CMV and contribute to the ongoing debate about the importance of screening for CMV during pregnancy.  

Role of fetal magnetic resonance imaging in fetuses with congenital cytomegalovirus infection: multicenter study

Postnatal prognosis in cases with congenital cytomegalovirus (CMV) infection is strongly dependent on the presence of structural anomalies, highlighting the importance of prenatal imaging-based screening. The multicenter study by Di Mascio et al. investigates the role of magnetic resonance imaging (MRI) of the fetal brain in cases with congenital CMV infection. The study suggests an incremental detection rate by MRI of about 10% when screening fetuses with CMV infection and normal neurosonography. The results also highlight the prognostic value of CMV viral load, which was shown to be the only independent predictor of fetal anomaly detection on MRI. Overall, these findings support the value of a detailed imaging follow-up throughout pregnancy following diagnosis of fetal CMV infection and the use of fetal MRI in cases with negative neurosonography to improve prenatal counseling.

Coming up next month…

  • Newly updated ISUOG Practice Guidelines on the performance of fetal magnetic resonance imaging.
  • A systematic review and meta-analysis investigating the long-term outcome of children of women with cytomegalovirus infection in pregnancy and negative amniocentesis. Preview the Accepted Article.
  • A national cohort study investigating the association of placental and umbilical cord abnormalities with cerebral palsy. Preview the Accepted Article.
  • A systematic review and meta-analysis on maternal and perinatal outcomes of pregnancies complicated by poxvirus infection. Preview the Accepted Article.