[Decreased fetal movement and a sinusoidal pattern on the cardiotocogram: 2 alarm signals]

A 24-year-old primigravida was referred at 35 weeks of gestation due to decreased foetal movement. External monitoring demonstrated a sinusoidal foetal heart rate pattern accompanied by late decelerations. A hydropic and severely anaemic infant with clinical signs of thrombocytopenia was delivered by emergency caesarean section. He failed to breath spontaneously and required positive pressure ventilation. Cranial ultrasound and computerised tomography of the brain revealed a massive intraparenchymal haemorrhage. After the infant had died, post mortem studies revealed the presence of maternal antibodies to the human platelet antigen (HPA) 1a which suggested neonatal isoimmune thrombocytopenia as cause of the intracranial haemorrhage. A sinusoidal foetal heart rate pattern is an alarm signal--it is not necessarily significant but is often associated with mortality or serious morbidity and is therefore a reason for quickly investigating the condition of the foetus.