A river can make it nearly impossible to travel from one land mass to another - the divide is an impasse even if the land is close together.
In Placental Abruption, blood divides the uterine wall and the placenta prematurely - before birth(1). Blood accumulates and flows between them, halting fetal perfusion. The greater this divide becomes, the higher the risk for maternal hemorrhage and fetal hypoperfusion(1,3,7).
Let's start by briefly refreshing our knowledge of placental anatomy, where this problem originates.
The Divide
When the connection between maternal and fetal circulation is ideal, it should look like the picture below. If you're like me, your brain nearly checks out when looking at one of these placental anatomy graphics(2). However, it's not as complex as it seems at first glance.
I like to think of this connection as maternal and fetal hand-holding. The baby reaches out with the main stem villus, and the mother reaches out with projections from the placental septum (think of these like interlaced fingers).
If the hands start to separate, the bond weakens and can break. The bleeding can be caused by fetal vessel rupture, but it's more common for the ruptured vessels to be either maternal veins, arteries, or both.
While researching this topic, I couldn't help but notice some similarities between placental abruption and epidural and subdural hematomas5. On the one hand, the typical epidural bleed is arterial and rapidly expands, often showing very acute and severe signs and symptoms6. On the other hand, a subdural bleed can be chronic and venous in origin and may take time to start showing clinically significant signs of bleeding. How does this compare to placental abruption?
An acute placental abruption that is arterial in origin can cause the placenta to dissect extensively through the placental-decidual interface at an alarming rate6,7. These bleeds cause concern for maternal hemorrhage and disseminated intravascular coagulation (DIC). On the fetal side, distress can be noted through fetal heart rate monitoring (Cat. II or III patterns)(6,7).
If the bleed is venous in origin, the process may be limited to a smaller placental area and persist intermittently over time(6). On the maternal side, this might be appreciated as intermittent bleeding. On the fetal side, oligohydramnios (low amniotic fluid) and fetal growth restriction may occur(8).
Regardless of the nature of the ruptured vessel (arterial vs. venous), the abruption can be either partial or complete, both of which refer to how much surface area becomes detached1. Both partial and complete abruptions can present with or without vaginal bleeding, depending on where the detachment takes place(1,3,7).
Because the detachment must reach the edge of the placenta to cause vaginal bleeding, large abruptions can occur without any bleeding. This is to say that the degree of separation and volume of vaginal bleeding is not a linear correlation. It would be a mistake to assume that a low/absent volume of vaginal bleeding means a small abruption - there could still be a severe internal hemorrhage.
Presentation and Diagnosis
The 'typical' placental abruption is said to present with(3):
Vaginal bleeding. Vaginal bleeding may be mild to profuse, but it's important to remember that it could be absent in the case of a concealed hemorrhage.
Abdominal and/or back pain. Pain and tenderness may be more severe in the abruption area (e.g., a posterior placental abruption may present with more back than abdominal pain).
Contractions. The uterus becomes irritated due to accumulated blood, causing contractions in correlation with bleeding. Contractions are typically frequent and low amplitude but can progress labor and become stronger with continued uterine irritation.
It may take time for a patient with a placental abruption to present all these signs and symptoms (6-48 hours and up to 5 days after the initial insult)(4). A pregnant patient who experienced abdominal trauma might feel fine immediately after the car crash, but hours later, bleeding may accumulate to a noticeable level.
In the last blog on maternal emergencies, we covered "PREVIA" for placenta previa. Placental abruption also has a memory aid for its typical presentation:
ABRUPT
A = Acute onset of abdominal pain, which can range from mild to severe
B = Bleeding, variable in presence and amount; concealed hemorrhage is a concern
R = Rigid abdomen, indicative of hemorrhage and uterine irritability
U = Uncomfortable, distressed patient presentation
P = Palpable tenderness over the uterus
T = Tense, often with contractions, reflecting uterine irritability
Many of the items above can seem similar to normal labor. An uncomfortable patient experiencing contractions, abdominal pain, and perhaps some vaginal bleeding doesn't sound like a 100% sure bet for placental abruption. However, if labor (preterm or term) was progressing very quickly (abrupt-ly), the uterus was tender and rigid, or there was a history that hinted towards abruption, that should cause you to think twice. Once the patient starts to show signs of hemorrhagic shock, such as hypotension, tachycardia, altered mental status, diaphoresis, decreased urine output, etc., the risk of maternal and/or fetal morbidity and mortality climbs quickly(3).
History and Cases
There are acute and chronic conditions that put a patient at higher risk for a placental abruption. information about the occurrence.
The acute items are apparent - any trauma that shakes the belly up4. The uterine wall is much more elastic than the placenta, which causes a sheering force at their interface with forceful movement. Some Chronic items include things like hypertension, multiparity, smoking, and illicit drug use. Those are the more common conditions, but it's a long list(1).
To highlight how different these presentations can be, here are two hypothetical cases of placental abruption:
Case 1 - Chronic: A 32-week pregnant patient reported intermittent light vaginal bleeding and mild abdominal discomfort for two weeks without any recent trauma. Stable upon prehospital assessment, she was transported in a lateral recumbent position with continuous monitoring, and an IV was placed. In the hospital, a partial placental abruption was diagnosed with ultrasound. The patient received steroids for fetal lung maturity and was observed until induced labor at 34 weeks, resulting in a healthy delivery.
Case 2 - Acute: Following a high-impact car crash, a 29-week pregnant patient presented with acute abdominal pain, rapid contractions, and shock, indicative of a concealed hemorrhage and suspected acute placental abruption. POCUS assessment performed. Prehospital interventions included volume resuscitation with blood products (IV access x2), oxygen administration, LLR, and rapid transport to a facility equipped for obstetric and surgical emergencies with pre-alert to OB. An emergency cesarean section was performed due to acute, complete placental abruption and fetal distress, leading to the delivery of a preterm infant who required NICU care and intensive maternal stabilization for hemorrhagic shock.
Treatment
The only true 'fix' for abruption is delivery in the OR3. In the meantime, treatment for placental abruption considers the maternal presentation and data collected by fetal monitoring. Treatment for an unstable mother includes standard intrauterine resuscitation items(9):
Positioning. Left Lateral Recumbent position to displace the womb off of the inferior vena cava.
Oxygenation/ventilation. Supplemental oxygen may be provided if there are signs of maternal hypoxia/hypoxemia.
Volume. Crystalloids may be used, but massive blood product transfusion may be needed. The patient should ideally have two IV sites.
Tocolytics. Tocolytics are rarely given to patients with placental abruption10. The tonic and contracted uterus may hold pressure on the bleed, and vasospasm may keep it at bay. Relaxing the muscles in the uterus and vessels may be counterproductive. Tocolytics are a good example of an intervention that should be guided under consultation for non-specialty teams.
Transport to a hospital with obstetric and surgical capabilities is a must. Alerting the receiving hospital of the suspected placental abruption allows them time to prepare for delivery and hemorrhage control soon after the patient arrives.
Conclusion
Placental abruption is a bleed you can't reach by yourself. Aggressive maternal stabilization techniques combined with rapid recognition and triage are what will give both patients the best chance at survival. Here are my main take-home points:
1. Placental abruption is a hemorrhage between the placenta and the uterine wall. It's most often caused by acute abdominal trauma, but it can be spontaneous and even chronic. This divide separates the perfusion interface between mother and fetus and can result in maternal hypovolemic shock and fetal hypoperfusion, both of which can be fatal.
2. The volume of vaginal bleeding does not necessarily correlate with the severity of the placental abruption. The patient's history and items such as pain, uterine tenderness and rigidity, and the nature of contractions are better indicators of severity.
3. ABRUPT: Acute onset of abdominal pain, Bleeding, Rigid abdomen, Uncomfortable, Palpable tenderness, and Tense with contractions. If patients fit this clinical picture, they likely need intrauterine resuscitation and a capable OB/surgical center (quickly).
Also, we'll soon have an episode of OB Icebergs (featuring Demi Wilkes) covering placental abruption coming to the Studio!
Thanks for reading!
References
1. Bączkowska, M., Kosińska-Kaczyńska, K., Zgliczyńska, M., Brawura-Biskupski-Samaha, R., Rebizant, B., & Ciebiera, M. (2022). Epidemiology, risk factors, and perinatal outcomes of placental abruption—detailed annual data and clinical perspectives from Polish tertiary center. International Journal of Environmental Research and Public Health, 19(9), 5148. https://doi.org/10.3390/ijerph19095148
2. Jansen, C. R., Kastelein, A. W., Kleinrouweler, C., Van Leeuwen, E., De Jong, K. H., Pajkrt, E., & Van Noorden, C. F. (2020). Development of placental abnormalities in location and anatomy. Acta Obstetricia et Gynecologica Scandinavica, 99(8), 983–993. https://doi.org/10.1111/aogs.13834
3. Schmidt P, Skelly CL, Raines DA. Placental Abruption. [Updated 2022 Dec 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482335/
4. Tikkanen, M. (2010). Placental abruption: Epidemiology, risk factors and consequences. Acta Obstetricia et Gynecologica Scandinavica, 90(2), 140–149. https://doi.org/10.1111/j.1600-0412.2010.01030.x
5. Khairat A, Waseem M. Epidural Hematoma. [Updated 2023 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK518982/
6. Tikkanen, M. (2010b). Placental abruption: Epidemiology, risk factors and consequences. Acta Obstetricia et Gynecologica Scandinavica, 90(2), 140–149. https://doi.org/10.1111/j.1600-0412.2010.01030.x
7. Brandt, J. S., & Ananth, C. V. (2023). Placental abruption at near-term and term gestations: Pathophysiology, epidemiology, diagnosis, and management. American Journal of Obstetrics and Gynecology, 228(5), S1313–S1329. https://doi.org/10.1016/j.ajog.2022.06.059
8. Ananth, C. V., Oyelese, Y., Srinivas, N., Yeo, L., & Vintzileos, A. M. (2004). Preterm premature rupture of membranes, intrauterine infection, and oligohydramnios. Obstetrics & Gynecology, 104(1), 71–77. https://doi.org/10.1097/01.aog.0000128172.71408.a0
9. Simpson, K., & James, D. C. (2005). Efficacy of intrauterine resuscitation techniques in improving fetal oxygen status during labor. Obstetrics & Gynecology, 105(6), 1362–1368. https://doi.org/10.1097/01.aog.0000164474.03350.7c
10. Han, C. S., Schatz, F., & Lockwood, C. J. (2011). Abruption-associated prematurity. Clinics in Perinatology, 38(3), 407–421. https://doi.org/10.1016/j.clp.2011.06.001