Sinusoidal rhythm
From CardioWiki
Sinusoidal rhythm (sinusoidal type of variability on the CTG curve) is a repetitive sinusoidal wave with an amplitude of 5–15 beats / min and a frequency of 3–5 cycles per minute. The number of accelerations and decelerations is minimal or absent at all. This type of cardiotocogram is most often associated with severe pregnancy disorders, in particular, fetal anemia, severe hypoxia, Rh incompatibility, placental abruption, infectious lesions, and fetal heart malformations. Sinusoidal rhythm for 20 minutes or more on CTG indicates a high risk of fetal death. If the conclusion says "sinusoidal rhythm - 0 min", then this is a very good indicator.