Arteriovenous malformation of vein of Galen as a rare non-hypoxic cause of changes in fetal heart rate pattern during labor Kamil Biringer 1 , Pavol Zubor 1 , Erik Kudela 1 , Branislav Kolarovszki 2 , Mirko Zibolen 3 and Jan Danko 1 Departments of 1 Gynecology and Obstetrics, 2 Neurosurgery, and 3 Neonatology, Comenius University in Bratislava, Jessenius Faculty of Medicine in, Martin, Slovak Republic Abstract The aim of this case report is to describe a rare non-hypoxic cause of pathological changes in fetal heart rate pat- tern during labor, and to determine management, including a description of important prenatal aspects when pathologic cardiotocographic recording is performed during labor. A fetus with rare arteriovenous malformation of the vein of Galen, which represents less than 1% of all intracranial arteriovenous malformations, was monitored by intrapartum external cardiotocography in the 37 + 5 gestational week. The baby was born by cesarean section because of signs of imminent intrauterine hypoxia on cardiotocography. However, metabolic acidosis was not confirmed in umbilical cord blood sampling. Despite intensive neonatal care management, the newborn died 31 h after delivery because of progressive cardiac decompensation, hypotension and multi-organ failure. Precise diagnosis of the abovementioned pathology, a pre-labor plan for delivery and postnatal prognosis assess- ment can significantly contribute to the avoidance of a misdiagnosis of fetal hypoxia and unnecessary operative delivery with marked medico-legal consequences. Key words: cardiotocography, fetal monitoring, intracranial arteriovenous malformation, vein of Galen. Introduction Routine intrapartum electronic fetal monitoring is based on external cardiotocography (CTG). Unfortunately, CTG has limited value for the prediction of intrauterine fetal hypoxia, leading to misdiagnosis and/or unneces- sary operative deliveries for fetal distress (ODFD). 1 Changes in CTG pattern can be caused by intrauterine hypoxic events or by different non-hypoxic conditions, such as arteriovenous malformation (AVM) of the vein of Galen, which is often accompanied by poor intrauter- ine and postnatal prognosis, if combined with cardiac failure. AVMs of the vein of Galen represent less than 1% of all intracranial AVMs. 2 The aim of this case report is to show the impact of AVM of the vein of Galen on the interpretation of CTG findings in terms of intrapartum fetal hypoxia as a potentially life-threatening condition. Precise diagnosis of the abovementioned pathology, a pre-labor plan for delivery and postnatal prognosis assessment can significantly avoid misdiagnosis of fetal hypoxia and unnecessary ODFD with marked medico- legal consequences. We present a case of 23-year-old primipara woman with an unremarkable history and uncomplicated pregnancy, with an AVM of the vein of Galen diagnosed by ultrasound in the 30 + 2 gestational week (gw), which was monitored by intra-partum external cardiotocography (CTG) in the 37 + 5 gw. Case Report A 23-year-old primipara woman with an uncompli- cated pregnancy, negative biochemical screening for Received: May 19 2015. Accepted: October 21 2015. Correspondence: Dr Kamil Biringer, Department of Gynecology and Obstetrics, Jessenius Faculty of Medicine, Comenius University in Martin, Kollarova 2, 036 01 Martin, Slovakia. Email: biringer@lefa.sk © 2015 Japan Society of Obstetrics and Gynecology 346 doi:10.1111/jog.12909 J. Obstet. Gynaecol. Res. Vol. 42, No. 3: 346–349, March 2016