View source for Third trimester bleeding

==Background==
*Third trimester bleeding (also termed antepartum hemorrhage) refers to vaginal bleeding occurring after 28 weeks gestational age through delivery<ref name="sakornbut">Sakornbut E, Leeman L, Fontaine P. Late pregnancy bleeding. ''Am Fam Physician''. 2007;75(8):1199-1206.</ref>
*Complicates 2–5% of all pregnancies<ref name="sakornbut"/>
*Is an obstetric emergency associated with significant maternal and fetal morbidity and mortality<ref name="gandhi">Gandhi M, Guo W. Prompt evaluation and treatment of third-trimester bleeding. ''Clin Obstet Gynecol''. 2020;63(4):751-760. PMID 33332831.</ref>
*The two most common causes — [[Placental Abruption|placental abruption]] and [[Placenta Previa|placenta previa]] — account for approximately half of all cases<ref name="gandhi"/>
*The remaining cases are attributable to less common etiologies (vasa previa, uterine rupture, cervical pathology) or remain unexplained
*The physiologic hypervolemia of pregnancy (30–50% increase in blood volume) may mask early signs of hemorrhagic shock, and clinicians should be aware that significant blood loss can occur before vital sign derangements appear<ref name="muench">Muench MV, Canterino JC. Vaginal bleeding in late pregnancy. ''Emerg Med Clin North Am''. 2019;37(2):251-264. PMID 30940370.</ref>

==Clinical Features==
===General===
*Vaginal bleeding — ranges from light spotting to massive hemorrhage; may be bright red, dark, or mixed with amniotic fluid
*Bleeding may be partially or completely concealed (e.g. in abruption)
*Abdominal or pelvic pain, uterine tenderness, or contractions may be present depending on etiology
*Signs of hemodynamic instability (tachycardia, hypotension, pallor, altered mental status) in severe cases
*Abnormal fetal heart rate patterns

===By Etiology===
====[[Placental Abruption]]====
*Most common cause of painful third trimester bleeding
*Classic triad: vaginal bleeding, abdominal/uterine pain, uterine contractions<ref name="brandt">Brandt JS, Ananth CV. Placental abruption at near-term and term gestations: pathophysiology, epidemiology, diagnosis, and management. ''Am J Obstet Gynecol''. 2023;228(5S):S1313-S1329. PMID 37164498.</ref>
*Uterus often tender and hypertonic ("woody" or "board-like")
*Concealed hemorrhage may present without vaginal bleeding but with pain, uterine irritability, and fetal distress<ref name="brandt"/>
*May be complicated by [[Disseminated intravascular coagulation|DIC]] in ~10% of cases (more common with fetal death)<ref name="sakornbut"/>
*Risk factors: hypertension/[[Preeclampsia|preeclampsia]], trauma, cocaine use, tobacco use, prior abruption, PPROM, advanced maternal age, multiparity

====[[Placenta Previa]]====
*Classic presentation is painless, bright red vaginal bleeding
*May have an initial "sentinel bleed" that is not immediately life-threatening<ref name="sakornbut"/>
*Bleeding may become profuse without warning
*Uterus is typically soft and non-tender
*Risk factors: prior cesarean delivery, prior previa, multiparity, advanced maternal age, smoking, IVF, multiple gestation

====[[Vasa Previa]]====
*Rare (~1 per 2,500 deliveries) but carries very high fetal mortality when undiagnosed<ref name="oyelese">Oyelese Y, Javinani A, Shamshirsaz AA. Vasa previa. ''Obstet Gynecol''. 2023;142(3):503-518. PMID 37590981.</ref>
*Onset of vaginal bleeding typically coincides with rupture of membranes
*Bleeding is of fetal origin; even small-volume blood loss can cause rapid fetal exsanguination
*Fetal heart rate tracing may show sinusoidal pattern or acute bradycardia
*Risk factors: velamentous cord insertion, bilobed/succenturiate placenta, low-lying placenta, IVF, multiple gestation<ref name="oyelese"/>

====[[Uterine Rupture]]====
*Most commonly occurs in women with prior uterine surgery (especially prior cesarean section) during trial of labor<ref name="tanos">Tanos V, Toney ZA. Uterine scar rupture – Prediction, prevention, diagnosis, and management. ''Best Pract Res Clin Obstet Gynaecol''. 2019;59:115-131.</ref>
*Presentation may include sudden severe abdominal pain, vaginal bleeding, loss of fetal station, cessation of contractions, and maternal hemodynamic instability
*Fetal bradycardia is often the earliest and most consistent sign<ref name="patel">Patel RM, Kaler M, Al-Soufi S, et al. Diagnosis and management of uterine rupture in the third trimester of pregnancy: a case series and literature review. ''Cureus''. 2023;15(6):e40060. PMID 37431303.</ref>
*Fetal parts may become palpable through the abdomen
*Risk factors: prior cesarean section (especially classical incision), myomectomy, uterine instrumentation, labor induction/augmentation, grand multiparity

==Differential Diagnosis==
*[[Placental Abruption]]
*[[Placenta Previa]]
*[[Vasa Previa]]
*[[Uterine Rupture]]
*[[Cervicitis]] / cervical lesion (polyp, ectropion, cancer)
*Bloody show / normal labor onset
*[[Chorioamnionitis]]
*Cervical or vaginal trauma
*Coagulopathy (inherited or acquired)
*[[Intrauterine fetal demise]]
*Marginal sinus rupture
*Placenta accreta spectrum

==Evaluation==
===Workup===
*Primary survey and maternal stabilization
**ABCs; two large-bore IVs, crystalloid resuscitation<ref name="muench"/>
**Continuous maternal vital sign monitoring
**Left lateral uterine displacement
*Laboratory studies
**CBC (serial hematocrit)
**Type and crossmatch (or at minimum type and screen)
**Coagulation panel: PT/INR, PTT, fibrinogen — screen for [[Disseminated Intravascular Coagulation|DIC]]
***Fibrinogen < 200 mg/dL is concerning for consumptive coagulopathy
**Metabolic panel
**[[Kleihauer-Betke test]] — especially if Rh-negative to calculate RhoGAM dosing
*Fetal assessment
**Continuous electronic fetal heart rate monitoring and tocometry
**Category III fetal heart rate tracings (absent variability with recurrent late/variable decelerations, bradycardia, or sinusoidal pattern) warrant emergent delivery
*Imaging
**Transabdominal ultrasound to assess:
***Placental location (rule out previa before any digital vaginal exam)
***Retroplacental hematoma (though sensitivity for abruption is limited)
***Fetal presentation, viability, and amniotic fluid volume
**Transvaginal ultrasound with color Doppler if vasa previa suspected<ref name="oyelese"/>

===Diagnosis===
*Placental abruption is primarily a '''clinical diagnosis'''; ultrasound has poor sensitivity (25–50%) because acute hemorrhage may be isoechoic to placental tissue<ref name="brandt"/>
*Placenta previa is diagnosed on ultrasound (transabdominal or transvaginal)
*Vasa previa is diagnosed by transvaginal ultrasound with color Doppler demonstrating fetal vessels over the internal os, confirmed with pulse-wave Doppler showing fetal heart rate waveform<ref name="oyelese"/>
*Uterine rupture is a clinical diagnosis; ultrasound may show free fluid, abnormal fetal lie, or absent myometrium, but operative findings are often required for confirmation<ref name="patel"/>
*Apt test (alkali denaturation test) can distinguish fetal from maternal blood when the source of bleeding is uncertain; fetal hemoglobin (HbF) resists alkali denaturation and remains pink, while adult hemoglobin (HbA) denatures and turns brown

====Critical Rule====
*'''Do NOT perform a digital vaginal examination until placenta previa has been excluded''' by ultrasound — digital exam in the setting of previa can precipitate catastrophic hemorrhage<ref name="sakornbut"/>
*Sterile speculum exam may be performed to evaluate the cervix and assess the source/quantity of bleeding

==Management==
*Resuscitation
**IV access with two large-bore (16–18 gauge) catheters
**Aggressive crystalloid resuscitation; initiate massive transfusion protocol if hemodynamically unstable
**Correct coagulopathy with blood products (pRBCs, FFP, cryoprecipitate, platelets) as indicated
*Rh immunoglobulin
**Administer [[RhoGAM]] (300 mcg) to all Rh-negative mothers
**Additional doses guided by Kleihauer-Betke quantification
*Fetal monitoring
**Continuous electronic fetal monitoring; ensure immediate operative delivery capability
*Condition-specific management
**Placental abruption
***Mild, with reassuring fetal status and preterm gestation: close inpatient observation, serial labs, consider antenatal corticosteroids if < 37 weeks
***Moderate-to-severe abruption, maternal instability, or nonreassuring fetal status: emergent delivery<ref name="brandt"/>
***If fetal demise has occurred, vaginal delivery is generally preferred to minimize maternal surgical morbidity<ref name="sakornbut"/>
***DIC: correct coagulopathy aggressively; target fibrinogen > 150–200 mg/dL
**Placenta previa
***If stable, not actively hemorrhaging, and preterm: inpatient observation, antenatal corticosteroids, plan for cesarean delivery at 36–37 weeks<ref name="sakornbut"/>
***Active hemorrhage or maternal/fetal instability: emergent cesarean delivery
***Tocolysis may be considered cautiously if preterm with contractions contributing to bleeding<ref name="sakornbut"/>
**Vasa previa
***Known diagnosis: planned cesarean delivery at 34–37 weeks of gestation<ref name="smfm">Society for Maternal-Fetal Medicine (SMFM); Sinkey RG, Odibo AO, Dashe JS. #37: Diagnosis and management of vasa previa. ''Am J Obstet Gynecol''. 2015;213(5):615-619. PMID 26292048.</ref>
***Acute bleeding with rupture of fetal vessels: emergent cesarean delivery and preparation for neonatal transfusion
**Uterine rupture
***Emergent cesarean delivery/laparotomy<ref name="patel"/>
***Uterine repair versus hysterectomy depending on extent of injury, hemodynamic stability, and future fertility desires
***Aggressive resuscitation and blood product administration
*Antenatal corticosteroids
**Administer betamethasone or dexamethasone for fetal lung maturity if 23–36+6 weeks gestation and delivery is anticipated, but do not delay emergent delivery for steroid administration<ref name="gyamfi">Gyamfi-Bannerman C. Society for Maternal-Fetal Medicine (SMFM) Consult Series #44: Management of bleeding in the late preterm period. ''Am J Obstet Gynecol''. 2018;218(1):B2-B8.</ref>
*MgSO4 for neuroprotection
**Consider magnesium sulfate for fetal neuroprotection if < 32 weeks gestation and delivery is imminent

==Disposition==
*All patients with third trimester bleeding require emergent OB consultation
*Admit for observation at minimum; most patients will require inpatient monitoring
*Indications for emergent delivery include:
**Maternal hemodynamic instability despite resuscitation
**Category III fetal heart rate tracing in a viable fetus
**Massive hemorrhage
**Suspected uterine rupture
**Ruptured vasa previa
*If at a facility without obstetric/surgical capability, stabilize and arrange emergent transfer
*Ensure neonatal resuscitation team (NICU) is available or on standby for all deliveries
*Social work and emotional support services as needed, particularly in cases of fetal demise

==See Also==
*[[Placental Abruption]]
*[[Placenta Previa]]
*[[Vasa Previa]]
*[[Uterine Rupture]]
*[[Intrauterine fetal demise]]
*[[Vaginal Bleeding (Pregnant)]]
*[[DIC]]
*[[Postpartum hemorrhage]]

==External Links==
*[https://pubmed.ncbi.nlm.nih.gov/33332831/ Prompt evaluation and treatment of third-trimester bleeding - Clin Obstet Gynecol 2020]
*[https://pubmed.ncbi.nlm.nih.gov/37164498/ Placental abruption at near-term and term gestations - Am J Obstet Gynecol 2023]
*[https://pubmed.ncbi.nlm.nih.gov/37590981/ Vasa Previa - Obstet Gynecol 2023]
*[https://pubmed.ncbi.nlm.nih.gov/26292048/ SMFM #37: Diagnosis and management of vasa previa - Am J Obstet Gynecol 2015]
*[https://pubmed.ncbi.nlm.nih.gov/30940370/ Vaginal bleeding in late pregnancy - Emerg Med Clin North Am 2019]

==References==
<references/>

[[Category:OBGYN]]