External cephalic version in fetal isolated mild ventriculomegaly

Abstract

I congratulate Prof. Paladini and colleagues on their recent Opinion1, which provides a concise and cogent review of the state of play as regards to referral of sonographically diagnosed cases of fetal isolated mild ventriculomegaly (IMV) for complementary fetal brain magnetic resonance imaging (MRI), and offers important suggestions to improve sonographic diagnosis in such cases and reduce the need for MRI referrals. There is considerable variation in the diagnostic yield of fetal ultrasound for identifying abnormalities of the central nervous system, with a concomitant variation in the rate of clinically relevant information revealed by subsequent MRI assessment. The authors advocate that, in fetuses with a suspicion of IMV, transabdominal ultrasound should be replaced by transvaginal scanning as first line of intervention. In case of breech presentation, they recommend that external cephalic version (ECV) be performed to allow for transvaginal imaging of the fetal brain. It should be noted that ECV has been associated with serious adverse maternal and fetal outcomes. Pooled complication rates of 6.1% were reported in a systematic review2, including stillbirth and placental abruption. A pooled risk of 0.24% (95% CI, 0.17–0.34%) was reported for serious complications while emergency Cesarean delivery was necessary in 0.35% (95% CI, 0.26–0.47%) of pregnancies that underwent ECV2. A more recent publication3 reported a corrected perinatal mortality rate of 0.12% in a large cohort of pregnancies that underwent ECV at term. It has also been shown that the success of ECV is improved when it is performed by a dedicated trained team of practitioners4. Neurosonography should be performed by properly trained specialists using suitable machines. Referral to MRI to investigate suspicious brain lesions may be appropriate when ultrasound falls short. While transvaginal scanning can improve visualization in many cases, in others, particularly near term with the fetus in breech presentation, ultrasound may not be sufficient. ECV should only be undertaken when the patient has shown that she understands the implications of the procedure and signed an informed consent, and when suitable conditions are met, including the presence of expert practitioners, availability of a labor and delivery ward, preparations for an emergency Cesarean delivery and access to a neonatal intensive care unit, particularly at the stage of fetal viability.