Background: To describe the brain Doppler changes in fetuses with isolated open spina bifida (OSB).
Study design: Doppler ultrasound measurements including the umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, and their combination into the cerebroplacental ratio (CPR) and umbilicocerebral ratio (UCR) were performed in a cohort of fetuses with OSB. Included patients were individually matched to a control group without structural anomalies and similar gestational ages. MCA-PI and/or CPR values below the 5th centile were considered abnormal and indicative of cerebral blood redistribution, while UCR and UA-PI above the 95th centile were considered abnormal.
Results: During the study period, 266 fetuses were recruited, 133 normally grown fetuses with OSB and 133 matched controls. Doppler recordings were successfully obtained in all fetuses at a median gestational age of 30.9 weeks. All cases showed UA-PI within normal ranges, but fetuses with OSB showed significantly higher frequency of cerebral blood redistribution (15.0 vs. 3.0%, p < .01), MCA-PI <5th centile (10.5% vs. 3.0%, p = .01), decreased CPR (9.8% vs. 2.3%, p = .01) and increased UCR (17.2 % vs 7.5 %, p =.02). The rate of cerebral blood redistribution was significantly higher in the OSB group with ventriculomegaly in comparison to those with OSB and normal lateral ventricle diameter (18.6% vs. 3.2%, respectively; p <.05).
Conclusion: A proportion of fetuses with isolated open spina bifida showed cerebral blood redistribution.
Keywords: Cerebroplacental ratio; Doppler; middle cerebral artery; myelomeningocele; spina bifida.