Does normal fetal brain imaging in monochorionic twins following co-twin fetal demise eliminate the risk of adverse neurodevelopmental outcome?

Objective: To assess the residual risk of long-term adverse neurodevelopmental outcomes in monochorionic twins following co-twin fetal demise and normal fetal brain imaging.

Methods: All monochorionic twin pregnancies with co-twin fetal demise were included. Patients were identified through a search of inpatient medical records for co-twin fetal demise. Cases involving fetal demise following intrauterine procedures (e.g., laser ablation or termination of pregnancy following findings on fetal brain imaging) were excluded. Following co-twin demise, fetal brain imaging, including serial neurosonogram and fetal brain MRI, was performed on the surviving fetus. Neurodevelopmental outcomes were assessed postnatally using standardized age-appropriate developmental evaluation of personal-social, language, gross and fine motor skills, as well as hearing and vision screening. Additionally, parents completed a phone-based adaptive behavior questionnaire using the Vineland-II Adaptive Behavior Scales (VABS-II).

Results: Nineteen patients met the inclusion criteria. Two patients underwent urgent cesarean delivery due to fetal distress following co-twin demise and did not undergo any imaging. Of the 17 patients who underwent fetal brain imaging, 2 had evidence of CNS injury, one of whom later presented with mild speech delay, and the other who achieved an adequate VABS-II score. Among the fetuses with normal brain imaging and available follow-up, 45.4% (5/11) had abnormal developmental evaluations including one global delay, one motor delay, one mild hypotonia, and two moderately low scores on VABS-II.

Conclusion: Normal fetal CNS imaging following co-twin fetal demise in monochorionic twins does not guarantee normal neurodevelopmental outcome. This residual risk should be clearly discussed with parents during counseling to aid clinical decision- making.