A positive association between postpartum electrohysterography parameters and blood loss after vaginal delivery: A prospective study.

Introduction: The postpartum period can be complicated by hemorrhage, frequently caused by uterine atony. Electrohysterography, allowing continuous monitoring of uterine activity, may be a promising alternative for early detection of uterine atony, and thereby contribute to the prevention of postpartum hemorrhage. Associations between electrohysterographic parameters postpartum and total blood loss were studied.

Methods: In this prospective explorative study, women were included with a vaginal delivery between 36 and 42 weeks of gestation. Linear regression analysis was used to describe the association between electrohysterographic parameters (i.e. area under the contraction curve (AUC) total (in arbitrary units), AUC from baseline (in arbitrary units), maximum amplitude (in arbitrary units) and baseline tone (in arbitrary units)) and total blood loss (in mL) during the first 30 min postpartum.

Results: In total, 25 women were included for analysis, of whom three had postpartum hemorrhage. A moderate positive linear correlation was found between the logarithmically transformed total blood loss and the AUC total (r = 0.44, p = 0.03), AUC from baseline (r = 0.43, p = 0.03) and baseline tone (r = 0.43, p = 0.03). There was no significant linear correlation between the logarithmically transformed total blood loss and maximum amplitude. Explorative analysis revealed a significantly higher AUC total, AUC from baseline and baseline tone in women with postpartum hemorrhage compared to women without postpartum hemorrhage. (p = 0.02, p = 0.02 and p = 0.03, respectively).

Discussion: There is a moderate positive correlation between the logarithmically transformed total blood loss and the AUC total, AUC from baseline and baseline tone. Also, these parameters were all significantly higher in women with postpartum hemorrhage compared to women without postpartum hemorrhage.