In conjunction with significant cardiovascular adaptation, changes in cardioautonomic balance, specifically greater sympathetic activation and vagal withdrawal, are considered normal adaptations to healthy singleton pregnancy. Cardiovascular adaptation to twin pregnancy is more profound than that of singleton pregnancies; however, the changes in cardioautonomic control during multifetal gestation are unknown. To address this gap, beat-by-beat blood pressure (photoplethysmography) and heart rate (lead II electrocardiogram) were measured continuously in 25 twin pregnancies and 25 singleton pregnancies (matched for age, pre-pregnancy BMI and gestational age) during 10-minutes of rest. Data extracted from a 3- to 5-minute period was used to analyze heart rate variability (HRV), blood pressure variability (BPV), cardiovagal baroreflex gain and cardiac intervals as indicators of cardioautonomic control. Independent t-tests were used to determine statistical differences between groups (α=0.05) and the false rate discovery was determined to adjust for multiple comparisons. Resting heart rate was greater in twin compared to singleton pregnancies (91±10 vs. 81±10 bpm; P=0.001), but blood pressure was not different. Individuals with twin pregnancies had lower HRV, evidenced by lower standard deviation of R-R intervals (32±11 vs. 47±18 ms; P=0.001), total power (1035±810 vs. 1945±1570 ms²; P=0.004) and high frequency power (224±262 vs. 810±806 ms²; P<0.001) compared to singleton pregnancies. There were no differences in cardiac intervals, BPV and cardiovagal baroreflex gain between groups. Our findings suggest that individuals with twin pregnancies have greater sympathetic and lower parasympathetic contributions to heart rate and that cardiac, but not vascular, autonomic control is impacted during twin compared to singleton pregnancy.

中文翻译：

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健康单胎和双胎妊娠的心脏自主控制

结合明显的心血管适应，心血管自主平衡的改变，特别是更大的交感神经激活和迷走神经退缩被认为是对健康单身妊娠的正常适应。与单胎妊娠相比，心血管对双胎妊娠的适应更为深刻。但是，多胎妊娠期间心脏自主神经控制的变化是未知的。为了弥补这一差距，我们在10到10个月期间连续测量了25次双胎妊娠和25次单胎妊娠（与年龄，孕前BMI和胎龄相匹配）的逐次血压（光电容积描记法）和心率（II导联心电图）。分钟的休息时间。从3分钟到5分钟内提取的数据用于分析心率变异性（HRV），血压变异性（BPV），心脏迷走神经反射增加和心律间隔是心脏自主神经控制的指标。使用独立的t检验确定组之间的统计差异（α= 0.05），并确定错误率发现以调整多个比较。与单胎妊娠相比，双胞胎的静息心率更高（91±10比81±10 bpm； P = 0.001），但是血压没有差异。双胎妊娠患者的HRV较低，这由RR间隔的标准差较低（32±11 vs. 47±18 ms； P = 0.001），总功率（1035±810 vs. 1945±1570 ms）证明。与单胎妊娠相比，双胞胎的静息心率更高（91±10比81±10 bpm； P = 0.001），但是血压没有差异。双胎妊娠患者的HRV较低，这由RR间隔的标准差较低（32±11 vs. 47±18 ms； P = 0.001），总功率（1035±810 vs. 1945±1570 ms）证明。与单胎妊娠相比，双胞胎的静息心率更高（91±10 vs. 81±10 bpm； P = 0.001），但血压没有差异。双胎妊娠患者的HRV较低，这由RR间隔的标准差较低（32±11 vs. 47±18 ms； P = 0.001），总功率（1035±810 vs. 1945±1570 ms）证明。² ; P = 0.004）和高频能量（224±262 vs. 810±806 ms ² ; P <0.001）与单胎妊娠相比。两组之间的心律间隔，BPV和心房压力反射增加没有差异。我们的发现表明，双胎妊娠的个体对心率的交感更大而副交感神经的贡献更低，与单胎妊娠相比，双胎期间心脏（而非血管）自主控制受到影响。