Atypical Intrapartum Maternal Heart Rate Pattern in a Woman with Paroxysmal Supraventricular Tachycardia

Pregnant women show characteristic hemodynamics, and their heart rates ordinarily increase with uterine contractions during labor. Conversely, uterine contraction-associated decelerations of maternal heart rate (MHR) are rare. We present a pregnant woman with paroxysmal supraventricular tachycardia (PSVT) who exhibited intrapartum MHR deceleration pattern. We performed simultaneous fetal heart rate monitoring with an external ultrasound transducer and MHR monitoring with a tocogram during her parturition. She developed a PSVT exacerbation in the second stage of parturition. As revealed by cardiotocography, the MHR baseline abruptly declined at onset of uterine contractions during the active phase of labor. Recovery followed, and the contraction resolved. The tachycardia got prolonged as the labor advanced. Our patient exhibited the unusual, up-and-down changes of the MHR pattern associated with labor contractions. The etiology of the occurrence of uterine contraction-associated MHR decelerations was unclear in the present case. Continuous tracing to visually inspect MHR patterns during parturition is a simple method for examining real-time MHR status of patients treated within obstetric practice settings.