Original scientific paper
ELECTRICAL ACTIVITY OF MYOMETRIUM DURING LABOR INDUCTION BY OXYTOCINE AND SHAPES OF PROSTAGLANDINE
Tibor Toth
Abstract
Objectives. To find out whether non-invasive method for recording uterine muscle electrical activity could help development of mechanical myometrium activity during induced labor. Study design. Myometrium electrical activity during the labor induction was analysed in 110 gravidas hospitalized in Maternity Department of General hospital in Bjelovar. Medium for labor induction at 54 pregnant patients was oxytocine infusion, at 20 intracervical prostaglandine (dinoprostone 0.5 mg), at 21 intravaginal prostaglandine (dinoprostone 2 mg) and at 15 pregnant women intravenous application of prostaglandine (dinoprostone 0.75 mg). Electromyographical measurement has been done after 30, 90, 150 and 270 minutes after application of medium for labor induction. In all pregnancies there was electromyograficaly proved silence of uterus before the beginning of research. Characteristics of electrical bursts were analyzed separately (number of impulses, amplitudes, series, shape) and each record was merged by index of uterine activity according to Škrablin-Kučić formula: uterine activity index (UAI)= number of impulses during 10 minute period + amplitude (µV) of highest potential divided by 100, by which the series of bursts were marked by aditional 20, biphasic waves with 2 and polyphasic with 3. The received values of EMG UAI were analysed considering modified Bishop’s cervical score (<5, 5–8 and >8), gestation weeks (37th to 41th week) and parity (nulliparous and multiparous). Results. At induction of delivery by infusion of oxytocine statistically significant differences in values of EMG UAI were estabilished between the gravidias with various ripeness of the cervix (p<0,05). The statistically significant difference also exists between the groups of modified cervical Bishops score <5 and 5–8 after 30th minute of induction, and between cervical index 5–8 and >8 starting 210 minutes after induction. The lowest average values of EMG UAI were measured in the group of gravidas with modified Bishop’s score <5, the highest values at the score >8. During the same method of induction the statistically significant difference of EMG UAI between the gravidas with different pregnancy weeks was proved. The highest average values were established in gravidas at 41st week of pregnancy, the lowest at the 37th week (p<0,05). There was not proved the relationship between parity and value of EMG UAI (p>0.05). When the intravaginal (dinoprostone 2 mg) and intravenous prostaglandine (dinoprostone 0.75 mg) were used, no statistically significant difference in values of EMG UAI in the gravidas with different cervix maturity (p>0.05) was estabilished. Not any of the three prostaglandine ways for labor induction shows the statistically significant difference of values of the EMG UAI presented at labour induction in gravidas with various pregnancy weeks (p>0.05). The statistical difference was not proved with regard to parity, except when i.v. prostaglandine was used: and thereby was proved the statistically higher EMG UAI by nulliparous pregnancies after 150 minutes of induction (p<0.05). Conclusion. Registering the action potentials from the skin surface in pregnant patients with specially adapted mechanism and cutaneous electrodes is an uninvasive diagnostic method that is positively correlated to the outcome of induced labor and could be useful in the control of the mechanical activity of myometrium.
Keywords
human myometrium; electrical activity; induced labor
Hrčak ID:
9588
URI
Publication date:
31.3.2005.
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