> see [[antepartum haemorrhage]] and section there about placental abruption for terser explanation of key points. also see [[Pregnant trauma]] section on [[Pregnant trauma#Pregnancy Trauma complications|obstetric trauma complications]] Placental abruption complicates 1% to 5% of patients with minor trauma and between 20% and 50% of cases with major trauma. The placenta *separates from the underlying decidua* because of shearing forces between the relatively inelastic placenta and the more elastic uterus. This **leads to fetal hypoxia and death**. Thromboplastin release may lead to the development of [[DIC|Disseminated Intravascular Coagulation]] (DIC). - The ==diagnosis== of abruption is based upon the presence of characteristic clinical features: ==vaginal bleeding, abdominal pain, contractions, uterine rigidity and tenderness, and possibly a nonreassuring fetal heart rate== (FHR) tracing. However, a significant abruption ==can be asymptomatic== or associated with minimal maternal symptoms, including the absence of vaginal bleeding. - **Investigations:** limited value — Sonographic and laboratory assessments (eg, platelet count and fibrinogen concentration) support the diagnosis if abnormal, but may be normal despite mild to moderate placental separation. *Ultrasound examination is of limited usefulness in diagnosing abruption*; an abruption is likely if a subchorionic hematoma is observed, but many abruptions are not visualized sonographically. CT and magnetic resonance imaging are never used clinically for evaluation of abruption, but if performed as part of a maternal trauma evaluation, they may show findings consistent with abruption. - [[CTG monitoring|Fetal monitoring]] — The importance of fetal heart rate and uterine contraction monitoring lie primarily in their *negative predictive value* for **abruptio placentae**. - As an example, one study reported no adverse outcomes directly related to trauma when monitoring was normal and early warning symptoms (bleeding, abdominal pain) were absent (negative predictive value 100 percent). In contrast, the presence of vaginal bleeding, uterine contractions, abnormal fetal heart rate monitoring, and/or abdominal pain or uterine tenderness was not highly predictive of either preterm delivery or adverse pregnancy outcome (sensitivity and specificity 52 and 48 percent, respectively). - The *amount of time the fetus should be monitored* is controversial, with recommendations ranging from 4 to 48 hours. The rationale for a prolonged period of monitoring is concern about delayed abruption, which has been reported up to six days after a traumatic event. However, the risk of a delayed abruption is extremely low. In the study described above, repetitive monitoring over several days did not uncover any patients whose fetal heart rate tracings evolved from normal to abnormal. - We suggest ==discontinuing continuous monitoring after four hours== if all of the following criteria are met: - Uterine contractions less frequent than 1 in 10 minutes (<6/hour) - Absence of vaginal bleeding - Absence of abdominal/uterine pain - Category 1 fetal heart rate tracing - Maternal vital signs stable and within acceptable range/baseline - The woman may be discharged if there are no maternal conditions requiring attention. - We suggest a **minimum 24-hour period of monitoring for women with any of the following**: - Abdominal bruising or other obvious abdominal injury - Regular contractions (≥1 in 10 minutes \[6/hour\]) - Vaginal bleeding - Abnormal fetal heart rate tracing - Abdominal/uterine pain - Coagulopathy (eg, low platelets or fibrinogen