Study On The Change Of Cardiac Reserve Function During Normal Vaginal Delivery

Objective: To investigate the trend of cardiac reserve function duringthe normal labor.Methods:63cases were chosen by randomly from hospitalizedmaternal women in the department of obstetrics of the first affiliatedhospital of Chongqing Medical University were involved in this study from2010June to December (six months). The digital technique of heart soundsignal processing was used to analysize cardiac reserve function parametersincluding the heart rate (HR), the ratio of the amplitude of the first heartsound to the second heart sound (S1/S2) and the ratio of diastolic tosystolic duration (D/S) of pregnant women.Results: Comparison of cardiac reserve function between uterinecontractions and relaxations during labor:①Latent phase of labor (Cervixdilation＜3cm): HR was（87.3±14.0beats/min）in uterine contractions and（82.8±12.6beats/min）in uterine relaxations；The ratio of D/S was（1.14±0.27）in uterine contractions and（1.21±0.22）in uterine relaxations,the comparisioons of the two were statistically significant, P＜0.05； Butratio of S1／S2was(2.19±0.82) in uterine contractions and (2.28±0.81) inuterine relaxations), the comparisons was not statistically significant，P＞ 0.05②During early active stage of labor (cervix dilation3-6cm)：HR was（89.3±15.3beats/min） in uterine contractions and (83.1±13.5beats/min)in uterine relaxations, P＜0.05；The ratio of D/S was （1.09±0.30）inuterine contractions and （1.20±0.27） in uterine relaxations, thecomparisions of the two were statistically significant, P＜0.05； But ratioof S1／S2was(2.42±1.08) in uterine contractions and (2.29±0.83) inuterine relaxations，the comparisons was not statistically significant，P＞0.05；③During late active stage of labor (cervix dilation6-10cm)，HR was95.4±18.7beats/min）in uterine contractions and (86.2±15.6beats/min）inuterine relaxations； The ratio of D/S was(1.01±0.25） in uterinecontractions and （1.18±0.25）in uterine relaxations, the comparisions ofthe two were statistically significant, P＜0.05；But the ratio of S1／S2was(2.61±1.26) in uterine contractions and (2.67±1.19) in uterinerelaxations，the comparisons was not statistically significant，P＞0.05；④The second stage of labor (cervical dilation≥10cm)： HR was（109.4±19.7beats/min） in uterine contractions and （93.5±16.7beats/min）in uterine relaxations；The ratio of D/S was（0.89±0.23） inuterine contractions and （1.14±0.26）in uterine relaxations； The ratio ofS1／S2was (3.66±1.37)in uterine contractions and (2.81±1.07) in uterinerelaxations, the comparisions of all were statistically significant, P＜0.05.(2)Comparison of the cardiac reserve function in uterine relaxation of eachstage of labor：maternal heart rate gradually increased from latent stage of labor to the second stage, and decreased postpartum, the comparisionsware statistically significant, P＜0.05; S1／S2gradually increased fromlatent stage of labor to the second stage, and decreased postpartum, thecomparisions ware statistically significant, P＜0.05; but the ratio of D/Sgradually decreased from Latency to the second stage of labor, andincreased postpartum, the comparisions ware statistically significant, P＜0.05.(3)Comparison of the cardiac reserve function in uterine of each stageof labor： maternal heart rate gradually increased from latent stage of laborto the second stage, the comparisions ware statistically significant, P＜0.05；ratio of S1／S2gradually increased from latent stage of labor to thesecond stage, the comparisions ware statistically significant, P＜0.05; theratio of D/S gradually decreased from Latency to the second stage of labor,ratio of S1／S2gradually increased from latent stage of labor to thesecond stage, the comparisions ware statistically significant, P＜0.05.Conclusions： The maternal cardiac reserve function decreased inuterine contractions than relaxation during labor; With the progress oflabor,the maternal cardiac reserve function declined, especially in the secondstage of labor, and recovered in postpartum stage. Non—invasive test of thecardiac reserve function for the maternity could be widely used clinically．...