Idiopathic vaginal bleeding during pregnancy as the only clinical manifestation of intrauterine infection

Abstract

MIAC was detected in 14% of patients with 'idiopathic' vaginal bleeding and was associated with subsequent preterm PROM and early preterm delivery. Vaginal bleeding may be the only clinical manifestation of MIAC, and it predisposes to adverse outcome.

Risk of preterm delivery in relation to vaginal bleeding in early pregnancy

“…As previously reported, first trimester vaginal bleeding was associated with a 2-fold increased risk of preterm delivery (2). These findings were corroborated by several other investigators (3)(4)(5)(6) and are consistent with conclusions drawn from a meta-analysis on the subject (7). Few studies have attempted to evaluate risk of specific preterm delivery sub-types (e.g., spontaneous preterm labor, preterm premature rupture of membranes and medically induced preterm delivery) (5,6).…”

“…Investigators have speculated that decidual thrombosis, ischemia and necrosis may all lead to vaginal bleeding which can trigger a pro-inflammatory response and stimulate tissue factor release and thrombin formation (3,(17)(18)(19). Consequently, thrombin is thought to act as an uterotonic agent that may stimulate uterine contractility leading to spontaneous preterm labor.…”

“…Collectively, available data suggest possible heterogeneity of associations of preterm delivery subtypes with vaginal bleeding. Specifically, it appears that vaginal bleeding may be more strongly related with preterm premature rupture of the membranes, and very preterm delivery (3,4,6) than with other preterm delivery subtypes. On the basis of this emerging evidence, we used data from a large cohort to further evaluate the relation between vaginal bleeding during the first and second trimester with preterm delivery.…”

“…Few studies have attempted to evaluate risk of specific preterm delivery sub-types (e.g., spontaneous preterm labor, preterm premature rupture of membranes and medically induced preterm delivery) (5,6). A small emergent literature suggests the merits of evaluating putative preterm delivery risk factors, such as vaginal bleeding, for each of the major subtypes of preterm delivery, as well as for moderate and very preterm delivery, respectively (3)(4)(5)(6). Collectively, available data suggest possible heterogeneity of associations of preterm delivery subtypes with vaginal bleeding.…”

Placental vascular pathology and increased thrombin generation as mechanisms of disease in obstetrical syndromes

“…To further understand how does thrombin affect the duration of pregnancy and the clinical phenotype of patients with the obstetrical syndromes we need to consider what are the mechanisms leading to thrombin generation and how it affects the feto-maternal unit. Increased thrombin generation can result from the following underlying mechanisms: 1) decidual hemorrhage that leads to a retro-placental clot formation 42 ; 2) intra-amniotic infection/inflammation which can induce decidual bleeding and sub-clinical abruption 43 , as well as increased intra-amniotic TAT complexes 37 ; and 3) an increased maternal systemic inflammatory response 44 that may activate the extrinsic pathway of coagulation due to the expression and release of TF by activated monocytes 45 . Thrombin affects many systems including also the following: 1) stimulation of decidual cell secretion of matrix metalloproteinase (MMP) (i.e.…”