Authors’ response to the comment on “Antepartum hemorrhage from previous-cesarean-sectioned uterus as a potential sign of uterine artery pseudoaneurysm”

Abstract

Thanks for the good comment by Matsubara et al. (2017) on our case of “antepartum hemorrhage from previous-cesarean-sectioned uterus as a potential sign of uterine artery pseudoaneurysm” (Zhang et al., 2017), published in the Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology). In the comment, the authors clarified two possibilities of our scenario: the uterine artery pseudoaneurysm (UAP) could be newly formed in the present delivery as a result of vulnerability of uterine artery and/or its branches at the site of previous cesarean section (CS) scar to exogeneous stimuli during labor contractions; the other possibility is that previous CS caused UAP formation but remained unruptured, and UAP continued to be intrauterine, a hyper-dynamic state during labor causing UAP-sac rupture and resultant antepartum hemorrhage, as well as postpartum hemorrhage.

Thanks for the good comment by Matsubara et al. (2017) on our case of “Antepartum hemorrhage from previous-cesarean-sectioned uterus as a potential sign of uterine artery pseudoaneurysm” (Zhang et al., 2017), published in the Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology). In the comment, the authors clarified two possibilities of our scenario: the uterine artery pseudoaneurysm (UAP) could be newly formed in the present delivery as a result of vulnerability of uterine artery and/or its branches at the site of previous cesarean section(CS) scar to exogeneous stimuli during labor contractions; the other possibility is that previous CS caused UAP formation but remained unruptured, and UAP continued to be intrauterine, a hyper-dynamic state during labor causing UAP-sac rupture and resultant antepartum hemorrhage, as well as postpartum hemorrhage.

We agree with the above two possible scenarios involved in the UAP formation, and these bring out some interesting questions: How to define the source of UAP formation? Could we conclude that the UAP formation in our case was not necessarily linked with traumatic procedure-associated consequence? How to define the traumatic procedure-associated UAP? Generally, most researchers or clinicians regard the so-called “traumatic procedure” as the immediate or the present traumatic operation involved in the current delivery. In this regard, our case is a typical UAP example unrelated to a traumatic event. While writing the case report last year, we found 18 cases of UAP rupture after non-traumatic delivery/pregnancy termination by searching English-language published work in the PubMed database, and 6 of 18 patients had a history of prior traumatic procedure. Almost all the published papers acknowledged the “traumatic procedure” as the present event occurring in the current delivery, rather than in the previous history.

However, this comment raised our in-depth and prudent consideration on the definition of traumatic-related UAP, and the traumatic event should be clearly classified in each case including “just preceding (the last) delivery”, “the second last delivery/abortion”, and even any history of a traumatic event. As the comments indicated, all prior history deliveries may have responsibility for UAP (Baba et al., 2016). Most interestingly, a lag time between a preceding event and manifestation/detection of UAP may sometimes be very long, such as the 10 years and even 20 years after CS as mentioned in the comment.

The clarification of traumatic event should be stressed in future cases, as “all prior history of deliveries” even 20 years ago (Papadakos et al., 2008) may prove to be the culprit of UAP. This is very meaningful and helpful for clinicians in keeping a high awareness on UAP formation. Furthermore, we would like to stress that although the mechanism of UAP formation is largely unknown due to the diversity of its clinical features, the potential risk factors should be particularly noted including scarred uterus, traumatic procedures, precipitous delivery, uterine infection, and underlying vascular abnormality. Thirdly, UAP may manifest not only as postpartum hemorrhage but also as antepartum hemorrhage (Cornette et al., 2014).