[Clinical evaluation of pseudosinusoidal fetal heart rate pattern associated with abruption placentae].

From retrospective studies of fetal heart rate records on abruption placentae, six cases with the pseudosinusoidal FHR pattern (pseudosinusoidal pattern) are reported. The pseudosinusoidal pattern has the following characteristics: 1) oscillation frequency synchronized with the frequency of uterine contractions, 2) an amplitude of 19bpm or more, which is positively correlated with the area of placental separation, 3) uniform frequency and amplitude, 4) a frequency of 1.3 cycles/min or less, which is clearly different from the true sinusoidal pattern. It seems that this characteristic pseudosinusoidal pattern appeared with decreased fetoplacental blood flow, which was initiated by abruption placentae and superimposed by uterine contractions. Since this pattern indicates progressive fetal jeopardy, an emergency delivery should be performed for intact survival.