Spontaneous tachysystole as sign of serious perinatal conditions.

We present three cases of spontaneous tachysystole, related to severe myometrium infection and to atypical partial placental abruption. Tachysystole was, in all three cases, associated with repetitive and frequent late decelerations, displaying a pseudo-sinusoidal fetal heart rate (FHR) pattern. Tachysystole, with a pseudo-sinusoidal FHR pattern, may be a sign of a critical perinatal condition and recognition may be of vital importance.