The association between myometrial electrical activity and time to delivery in threatened preterm labor.
OBJECTIVE
To assess the association between myometrial electrical activity and time-to-delivery in preterm labor using uterine electromyography.


METHODS
Myometrial electrical activity was measured via the electrical uterine monitor (EUM) device. Data was prospectively collected among women admitted due to suspected preterm labor, prior to 34 weeks of gestation. EUM-Index was defined as the mean electrical activity of the uterine muscle over a period of 10 minutes measured in units of microjoule (μJ, microwatt second). The association between the EUM-Index at admission to time-to-delivery and delivery prior to 34 weeks of gestation was calculated.


RESULTS
Overall, 45 women were included in the study. EUM-Index combined with cervical dilatation, demonstrated significant correlation to time-to-delivery (R(2 )= 0.49, p = 0.005), which was strengthened for women presenting prior to 28 weeks of gestation. EUM-Index above the median (>3.05 MJ) was significantly associated with a shorter latency period for delivery (36.0 ± 19.4 vs. 50.2 ± 25.9 days, p = 0.04). For delivery prior to 34 weeks, the EUM-Index showed an AUC = 0.65 (95% CI 0.48-0.82), and a cutoff of 2.5 MJ provided 91.7% sensitivity and 93.3% negative predictive value.


CONCLUSIONS
EUM-Index at time of admission due to suspected preterm labor is inversely correlated with time-to-delivery and may effectively rule out preterm delivery prior to 34 weeks.
a Helen Schneider Hospital for Women, Rabin Medical Center, Israel and the Sackler Faculty of Medicine, Tel Aviv University , Tel Aviv , Israel.
Amir
A
Aviram
a Helen Schneider Hospital for Women, Rabin Medical Center, Israel and the Sackler Faculty of Medicine, Tel Aviv University , Tel Aviv , Israel.
Liran
L
Hiersch
a Helen Schneider Hospital for Women, Rabin Medical Center, Israel and the Sackler Faculty of Medicine, Tel Aviv University , Tel Aviv , Israel.
Eran
E
Ashwal
a Helen Schneider Hospital for Women, Rabin Medical Center, Israel and the Sackler Faculty of Medicine, Tel Aviv University , Tel Aviv , Israel.
Yariv
Y
Yogev
a Helen Schneider Hospital for Women, Rabin Medical Center, Israel and the Sackler Faculty of Medicine, Tel Aviv University , Tel Aviv , Israel.
Eran
E
Hadar
D000328:Adult; D002584:Cervix Uteri / Q000502:physiology; D004576:Electromyography / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006801:Humans; D016014:Linear Models; D007752:Obstetric Labor, Premature / Q000503:physiopathology*; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D014590:Uterine Contraction / Q000502:physiology*; D018590:Uterine Monitoring / Q000379:methods*; D055815:Young Adult
Contractions; myometrial electrical activity; preterm delivery; time-to-delivery