Souma M L, Cabaniss C D, Nataraj A, Khan Z
Am J Obstet Gynecol. 1983 Feb 1;145(3):274-8. doi: 10.1016/0002-9378(83)90710-x.
Four hundred forty-two studies of the Valsalva maneuver were performed on 282 pregnant subjects and 37 nonpregnant female control subjects. A fetal monitor was used for graphic presentation of the subject's beat-to-beat heart rate changes. The Valsalva ratio was calculated, defined as maximum tachycardia divided by maximum bradycardia during a Valsalva maneuver. The data from the studies on pregnant subjects were grouped according to weeks of gestation: less than 13, 13 to 16, 17 to 20, 21 to 24, 25 to 28, 29 to 32, 33 to 36, and greater than 36. The mean Valsalva ratio for control subjects is higher than the mean for every gestation group, and there is a definite downward trend in the means for each successive gestation group through 29 to 32 weeks. The tendency for pregnant women to have an "abnormal" Valsalva ratio (that is, less than 1.5) also appears to be related to gestation. This exploratory study demonstrates that the Valsalva ratio is sensitive to physiologic changes associated with pregnancy. This test might have use as a noninvasive indicator of certain types of abnormalities associated with pregnancy.
对282名孕妇和37名非孕女性对照受试者进行了442次瓦尔萨尔瓦动作研究。使用胎儿监护仪来图形化显示受试者逐搏心率变化。计算瓦尔萨尔瓦比值，定义为瓦尔萨尔瓦动作期间最大心动过速除以最大心动过缓。对孕妇的研究数据根据孕周分组：小于13周、13至16周、17至20周、21至24周、25至28周、29至32周、33至36周以及大于36周。对照受试者的平均瓦尔萨尔瓦比值高于每个孕周组的平均值，并且在29至32周之前，每个连续孕周组的平均值都有明显的下降趋势。孕妇出现“异常”瓦尔萨尔瓦比值（即小于1.5）的倾向似乎也与孕周有关。这项探索性研究表明，瓦尔萨尔瓦比值对与妊娠相关的生理变化敏感。该测试可能用作与妊娠相关的某些类型异常的非侵入性指标。
