This document discusses third-trimester bleeding during pregnancy. It can be caused by conditions like abruptio placentae (AP), placenta previa (PP), and vasa previa (VP). AP is the premature separation of the placenta from the uterine wall. PP is the presence of placental tissue over the cervical os. VP occurs when umbilical cord vessels lie in the membranes over the cervical os. These conditions can lead to significant maternal and fetal risks if not properly managed. The document outlines the epidemiology, etiology, complications, diagnosis, and management considerations for each condition.

1. Third-Trimester Bleeding
Hasan Ismail
July 2015

2. Third-trimester bleeding, ranging from spotting to
massive hemorrhage, occurs in 2% to 6% of all
pregnancies. The differential diagnosis includes:
Bloody show from labor
Abruptio placentae (AP)
Placenta previa (PP)
Vasa previa (VP)
Cervicitis, postcoital bleeding, trauma, uterine
rupture, and carcinoma.
 AP, PP, and VP can lead to significant maternal
and fetal morbidity and mortality.

3. ABRUPTIO PLACENTAE
AP is the premature separation of the normally
implanted placenta from the uterine wall due to
maternal/uterine bleeding into the decidua
basalis.

6. Epidemiology
• One third of all antepartum bleeding is due to
AP, with an incidence of 1 in 75 to 1 in 225
births.
• AP recurs in 5% to 17% of pregnancies after
one prior episode and up to 25% after two
prior episodes. There is a 7% incidence of
stillbirth in future pregnancies after AP leading
to fetal death.

7. Etiology
• Bleeding does not correlate with abruption size.
• Blood in the basalis layer stimulates forceful, classically tetanic,
uterine contractions leading to ischemic abdominal pain.
• AP is associated with maternal hypertension, advanced maternal
age, multiparity, cocaine use, tobacco use, chorioamnionitis, and
trauma.
• Many cases are idiopathic.
• Chronic hypertension, superimposed preeclampsia, or severe pre-
ec-lampsia have fivefold increased risk of severe abruption
compared to normotensive women.

8. Antihypertensive
medications ??

9. • Cigarette smoking increases the risk of stillbirth from AP by
2.5-fold.
• Rapid changes in intrauterine volume can lead to
abruption, such as in rupture of membranes or therapeutic
amnioreduction with polyhydramnios or during delivery of
multiple gestations.
• Abruption occurs more frequently when the placenta
implants on abnormal uterine surfaces as with submucous
myomas or uterine anomalies.
• Hyperhomocysteinemia, Factor V Leiden, and prothrombin
20210 mutations (thrombophilias) are associated with an
increased risk of abruption.

10. Complications
• Hemorrhagic shock (if massive loss)
• Maternal (DIC) can occur and is found in 10% to 20% of AP
with stillbirth.
• Extravasation of blood directly into the uterine muscle
(Couvelaire's uterus) can lead to uterine atony and massive
postpartum hemorrhage.
• Fetal hypoxia may occur, leading to acute fetal distress,
hypoxic-ischemic encephalopathy,premature delivery, and
fetal death.
• Milder chronic abruption may lead to growth restriction,
major malformations, or anemia.

11. Diagnosis
History and Physical Examination
• Classically presents late in pregnancy with vaginal bleeding
and acute severe constantabdominal pain.
• Immediately : Maternal vital signs, fetal heart rate
assessment, and uterine tone
• Mark or record the fundal height to follow expansion of
concealed hemorrhage.
• Defer digital cervical exam until PP and VP have been R/O
• Ultrasound is insensitive in diagnosing AP, but large
abruptions may be seen as hypoechoic areas underlying the
placenta.
• Perform a speculum exam to evaluate vaginal or cervical
lacerations and the amount of bleeding.
• If discharge or signs of cervicitis are noted, obtain a wet
prep, potassium hydroxide slide (KOH), and cervical swabs
for gonorrhea and chlamydia testing.

12. Diagnosis
Laboratory Tests
• CBCD (<100,000 plts/mL suggests severe
abruption)
• Blood type and screen (cross-match should be
strongly considered)
• PT – PTT
• Fibrinogen (<200 mg/dL suggests severe
abruption) And Fibrin split-products
• Consider holding a whole blood specimen at the
bedside while lab work is pending. If a clot does
not form within 6 minutes or forms and lyses
within 30 minutes, DIC may be present.

13. The Apt test can be performed to evaluate
whether vaginal blood is from the mother or the
fetus.
The blood is collected and lysed in water to
release hemoglobin. Sodium hydroxide is mixed
with the supernatant. Fetal hemoglobin is
resistant to the base and will remain pink, while
maternal hemoglobin will oxidize and turn
brown

14. Management
• Large-bore intravenous access should be obtained.
• Fluid resuscitation should be initiated and a Foley
catheter placed to monitor urine output
• Close monitoring of maternal VS and fetal monitoring
should be maintained.
• Rh D immunoglobulin should be administered to Rh-
negative individuals.
Further management depends on the gestational age
and hemodynamic status of both mother and fetus.

15. Management
Term Gestation, Hemdynamically Stable
• Plan NVD with cesarean section for usual
indications and initiate induction of labor
• Follow serial hematocrit and coagulation studies.
• Consider fetal scalp electrode for accurate and
continuous fetal monitoring and intrauterine
pressure catheter to assess resting uterine tone.

16. Management
Term Gestation, Hemdynamically Unstable
• Aggressively fluid resuscitate.
• Transfuse PRBCs, FFP, and platelets as needed.
Maintain fibrinogen level >150 mg/dL, HCT
more than 25%, and platelets over 60,000/μL.
• Once the mother is stabilized, proceed to
urgent cesarean section

17. Management
Preterm Gestation, Stable
• Eighty-two percent of patients with evidence of AP at
<20 weeks' gestation will progress to term.
• In the absence of labor, preterm AP should be followed
closely with serial ultrasound evaluation of fetal
growth from 24 weeks and regular antepartum testing.
Steroids should be given to promote fetal lung
maturity.
• For preterm AP with labor and completely stable
hemodynamics and reassuring fetal signs, tocolysis
may be used in selected rare cases. Magnesium sulfate
tocolysis at <32 weeks‘ gestation may delay delivery,
giving time to administer a course of corticosteroids.

18. Management
Preterm Gestation, Unstability
Delivery should be performed after appropriate
resuscitation.

19. PLACENTA PREVIA
• PP is the presence of placental tissue over or near the
internal cervical os. It can be classified into four types
based on the location relative to the cervical os:
• complete or total previa, in which the placenta covers
the entire cervical os;
• partial previa, in which the margin of the placenta
covers part but not all of the internal os;
• marginal previa, in which the edge of the placenta lies
adjacent to the internal os;
• low-lying placenta, in which the placenta is located
near (within 2 cm) but not on the internal os.

21. Epidemiology
• In general, the incidence of PP is 1 in 200 to 1
in 390 pregnancies over 20 weeks' gestational
age.
• The frequency varies with parity, however,
giving an incidence of 0.2% in nulliparas and
as high as 5% in grand multiparas.

22. Etiology
• The most important risk factor for PP is a
previous C-sections. PP occurs in 1% of
pregnancies after a single C-sections. The
incidence after four or more C-sections increases
to 10% and 40-fold increased risk compared with
no C-sections.
• Other risk factors include increasing maternal age
(especially after age 40), multiparity, smoking,
residing at higher elevations, male fetus, multiple
gestation, and previous uterine curettage.

23. Complications
Bleeding occurs with the development of the
lower uterine segment in the third trimester in
preparation for labor. The placenta separates
and the thinned lower segment cannot contract
sufficiently to stop blood flow from the exposed
uterine vessels. Cervical exams or intercourse
may also cause separation of the placenta from
the lower uterine segment. Bleeding can range
from spotting to massive hemorrhage.

24. PP increases the risk for other abnormalities of
placentation:
• Placenta accreta. The placenta adheres
directly to the uterus without the usual
intervening decidua basalis.
• Placenta increta. The placenta invades the
myometrium but does not cross the serosa.
• Placenta percreta. The placenta penetrates
the entire uterine wall, potentially growing
into bladder or bowel.

25. • PP is associated with double the rate of fetal
congenital malformations, including anomalies
of the CNS, GI tract, cardiovascular system, and
respiratory system. No specific syndrome has
been identified.
• PP is also associated with fetal malpresentation,
preterm premature rupture of membranes,
intrauterine growth restriction, and VP.

26. Diagnosis
History and Physical Exam
• Seventy to 80% of PP presents with the acute
onset of painless vaginal bleeding with bright
red blood.
• The first bleeding episode is usually around 34
weeks. About one third of patients develop
bleeding before 30 weeks. The number of
bleeding episodes is unrelated to the degree
of PP or the prognosis for fetal survival.

27. • Medical, obstetric, and surgical history
• Other causes of vaginal bleeding must also be
ruled out, such as placental abruption.
• Maternal vital signs, abdominal exam, uterine
tone, and fetal heart rate monitoring
• Vaginal sonography is the gold standard for
diagnosis of previa. The placenta must be within
2 cm of the cervical os to diagnose
• If PP is present or suspected, digital examination
is contraindicated.
• A gentle speculum exam can be used to evaluate
the presence and quantity of vaginal bleeding,

28. Diagnosis
Laboratory Studies
• Complete blood cell count
• Type and cross-match
• Prothrombin time and activated
thromboplastin time
• Kleihauer-Betke test to assess for
fetomaternal hemorrhage in Rh-negative
unsensitized patients. Not useful for the
diagnosis of PP.
• Apt test (as described above for abruption).

29. Management
• Maintain strict pelvic rest (i.e., nothing in the
vagina, including intercourse or pelvic exams) and
avoid strenuous activity or exercise. They should
receive advice about when to seek medical
attention and be scheduled for fetal growth
ultrasounds every 3 to 4 weeks.
• In general, patients with PP, who are bleeding,
should be hospitalized for hemodynamic
stabilization and continuous maternal and fetal
monitoring.
• Laboratory studies
• Steroids between 24 and 34 weeks,
• Rh D immunoglobulin to Rh negative mothers.

30. • Management of placenta accreta, or its variants, can be
challenging. In patients with PP and a prior history of
cesarean section, cesarean hysterectomy may be
required. In cases where uterine preservation is highly
desired and no bladder invasion has occurred, bleeding
might be successfully controlled with selective arterial
embolization or packing of the lower uterine segment,
with removal of the pack through the vagina in 24 hr.
Specific management of PP is based on gestational age
and assessment of the maternal and fetal status

31. Management
Term Gestation, Hemodynamically Stable
• Patients with complete previa at term require
cesarean section.
• Patients with partial or marginal previa at
term may deliver vaginally, with thorough
consent regarding risks for blood loss and
need for transfusion. The staff and facilities for
immediate emergent Cesarean section must
be available

32. Management
Term Gestation, Hemodynamic Instability
• Stabilize the mother with fluid resuscitation
and blood products
• Delivery via cesarean section is indicated for
nonreassuring fetal heart monitoring,
lifethreatening maternal hemorrhage, or
bleeding after 34 weeks with documented
fetal lung maturity.
• If the mother is stable and intrauterine fetal
loss occurs or the fetus is <24 weeks‘
gestational age, NVD can be considered.

33. Management
Preterm Gestation, Hemodynamically Stable
• For each bleeding episode, the following are
recommended:
• Hospitalization until stabilized on bed rest with bathroom
privileges.
• Periodic assessment of maternal hematocrit and
maintenance of an active type and screen.
• Red blood cell transfusion as needed to maintain
hematocrit above 30% for slight but continuous bleeding.
• Corticosteroids and Rhogam as indicated.
• Fetal testing and growth ultrasounds to assess for
intrauterine growth restriction.
• Tocolysis is not warranted unless to administer a course of
steroids in an otherwise stable patient.

34. • After initial hospital management, outpatient
care may be considered if bleeding stops for >48
hr, no other complications exist, and the
following criteria are met:
The patient can maintain bed rest at home and is
adherent to medical care.
There is a responsible adult present at all times
who can assist in an emergency.
The patient lives near the hospital with
dependable transportation.

35. Management
Preterm Gestation, Hemodynamic Instability
Appropriate stabilization and resuscitation are
initiated with rapid delivery by cesarean section.

36. VASA PREVIA
VP occurs when the umbilical cord inserts into
the membranes, instead of the central placental
disc. When the vessels traverse the membranes
near the internal os in advance of the fetal
presenting part, they are at risk of rupture,
causing fetal hemorrhage.

38. Epidemiology
• The incidence of VP is between 1/1,000 and
1/5,000 pregnancies.
• Fetal mortality may be as high as 60% with
intact membranes and 75% when membranes
rupture.

39. Etiology
The cause of VP is unknown. One theory
suggests that it develops due to trophoblastic
growth and placental migration toward the
more vascular uterine fundus. The initial cord
insertion at the center of the placenta becomes
more peripheral as one portion of the placenta
actively grows and another portion does not.

40. Complications
• Even small amounts of fetal hemorrhage can
result in morbidity and possible death, due to
the small total fetal blood volume.
• Rupture of the membranes can result in rapid
exsanguination of the fetus.

41. History
• The patient usually presents with acute onset
vaginal bleeding after rupture of membranes.
• The bleeding is associated with an acute
change in fetal heart pattern. Typically, fetal
tachycardia occurs, followed by bradycardia
with intermittent accelerations.

42. Diagnosis
• Transvaginal ultrasound, in combination with
color Doppler ultrasonography, is the most
effective tool in antenatal diagnosis.
• In one study, there was a 97% survival rate in
cases diagnosed antenatally compared to a
44% survival rate in those without prenatal
diagnosis.

43. Management
• Third-trimester bleeding caused by VP is often
accompanied by acute and severe fetal
distress. Emergency cesarean section is
indicated.
• If VP is diagnosed antenatally, planned
cesarean section should be scheduled at 36 to
38 weeks under controlled circumstances and
before the onset of labor, to reduce fetal
mortality. Earlier delivery can be considered
with documented fetal lung maturity.