PATHOLOGIC OB: Page | 1

DULIG, Argent Aebi DP

ANTEPARTUM HEMORRHAGE

PLACENTAL ABRUPTION

• premature separation of the normally implanted placenta

Etiology

RISK FACTORS RELATIVE RISK

Increased age and parity 1.3–1.5

Preeclampsia 2.1–4.0

Chronic hypertension 1.8–3.0

Preterm ruptured membranes 2.4–4.9

Preterm ruptured membranes 2.1

Hydramnios 2.0

Cigarette smoking 1.4–1.9

Thrombophilias 3–7

Cocaine use NA

Prior abruption 10–25

Uterine leiomyoma NA

Pathology

• Initiated by hemorrhage into the decidua basalis.

• In its earliest stages consists of the development of a decidual hematoma that leads to

separation, compression, and the ultimate destruction of the placenta adjacent to it

• In some instances, a decidual spiral artery ruptures to cause a retroplacental hematoma,

which as it expands disrupts more vessels to separate more placenta

CONCEALED HEMORRHAGE

Retained or concealed hemorrhage is likely when:

� There is an effusion of blood behind the placenta but its margins still remain adherent.

� The placenta is completely separated yet the membranes retain their attachment to the

uterine wall.

� Blood gains access to the amnionic cavity after breaking through the membranes.

� The fetal head is so closely applied to the lower uterine segment that the blood cannot

make its way past it.

Signs and Symptoms Determined Prospectively in 59 Women with Abruptio Placentae

Sign or Symptom Frequency (%)

Uterine tenderness or back pain 78

66

Fetal distress 60

Preterm labor 22

High-frequency contractions 17

Hypertonus 17

Dead fetus 15

Differential Diagnosis

� Vaginal bleeding complicating a viable pregnancy, it often becomes necessary to rule

out placenta previa and other causes of bleeding by clinical inspection and ultrasound

evaluation.

� Painful uterine bleeding means placental abruption, whereas painless uterine bleeding

is indicative of placenta previa.

� Labor accompanying placenta previa may cause pain suggestive of placental abruption.

� Abruption may mimic normal labor, or it may cause no pain at all. The latter is more

likely with a posteriorly implanted placenta

CONSUMPTIVE COAGULOPATHY

� One of the most common causes of clinically significant consumptive coagulopathy in

obstetrics is placental abruption

� Overt hypofibrinogenemia (less than 150 mg/dL of plasma) along with elevated levels of

fibrinogen–fibrin degradation products, D-dimers, and variable decreases in other

coagulation factors are found in about 30 percent of women with placental abruption

severe enough to kill the fetus

� activation of plasminogen to plasmin, which lyses fibrin microemboli, thereby

maintaining patency of the microcirculation

RENAL FAILURE

• seen in severe forms of placental abruption, includes those in which treatment of

hypovolemia is delayed or incomplete

• Seriously impaired renal perfusion is the consequence of massive hemorrhage.

• vigorous treatment of hemorrhage with blood and crystalloid solution often prevents

clinically significant renal dysfunction

COUVELAIRE UTERUS

(UTEROPLACENTAL APOPLEXY)

� Widespread extravasation of blood into the uterine musculature and beneath the

uterine serosa

� occasionally seen beneath the tubal serosa, in the connective tissue of the broad

ligaments, and in the substance of the ovaries, as well as free in the peritoneal cavity

� seldom interfere with uterine contractions sufficiently to produce severe postpartum

hemorrhage

� Not an indication for hysterectomy.

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DULIG, Argent Aebi DP

Management for Abruptio placenta

PLACENTA PREVIA

In placenta previa, the placenta is located over or very near the internal os. Four degrees of this

abnormality have been recognized.

� Total placenta previa

The internal cervical os is covered completely by placenta

� Partial placenta previa

The internal os is partially covered by placenta

� Marginal placenta previa

The edge of the placenta is at the margin of the internal os.

� Low-lying placenta

The placenta is implanted in the lower uterine segment such that the

placenta edge actually does not reach the internal os but is in close proximity

to it.

� Vasa previa

The fetal vessels course through membranes and present at the cervical os

Factors associated with Placenta Previa:

� Advancing maternal age

At the extremes, it is 1 in 1500 for women 19 years of age or younger, and it is

1 in 100 for women older than 35 years of age.

� Multiparity

40 percent higher in multifetal gestations compared with that of singletons.

Previous pregnancies permanenetly damage the endometriu underlying the

placental site making suitable for the placenta in subsequent pregnancies

� Prior cesarean delivery

A prior uterine incision with a previa increases the incidence of cesarean

hysterectomy.

Defective vascularization of the deciduas as a result of inflammatory or

atrophic changes

� Smoking

Relative risk of placenta previa to be increased twofold

Carbon monoxide hypoxemia caused compensatory placental hypertrophy

Diagnosis

� Placenta previa or abruption should always be suspected in women with uterine

bleeding during the latter half of pregnancy.

� seldom be established firmly by clinical examination unless a finger is passed through

the cervix and the placenta is palpated. Such examination of the cervix is never

permissible unless the woman is in an operating room with all the preparations for

immediate cesarean delivery, because even the gentlest examination of this sort can

cause torrential hemorrhage

� safest method of placental localization is provided by transabdominal sonography

� Magnetic Resonance Imaging

PLACENTAL MIGRATION

� mechanism of apparent placental movement.

� The term migration is clearly a misnomer, however, because invasion of chorionic villi

into the decidua on either side of the cervical os persists.

� This difficulty is coupled with differential growth of lower and upper myometrial

segments as pregnancy progresses.

� Thus, those placentas that "migrate" most likely never had actual circumferential villus

invasion that reached the internal cervical os in the first place.

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DULIG, Argent Aebi DP

Management

Women with a placenta previa may be considered as follows:

� Those in whom the fetus is preterm and there is no indication for delivery.

� Target date: 37 weeks

� Hospitalization, replace blood loss, keep crossmatched blood available, bed rest under

close observation

� May go home provided that patient lives within 20-30 minutes from the hospital

� Those in whom the fetus is reasonably mature. Delivery by Cesarean section

Those in labor.

� General rule: method of delivery of choice in patients with degree of placenta previa is

Ceasarean section EXCEPT in cases of marginal or low lying placenta implanted

anteriorly with advanced cervical dilatation and head is engaged

� Those in whom hemorrhage is so severe as to mandate delivery despite fetal

immaturity.

ABRUPTIO PLACENTA PLACENTA PREVIA

History Frequent association of pre-

eclampsia or hypetension from

any cause

A single attack of vaginal

bleeding which usually continues

until delivery

Abdominal pain

No association with pre-eclampsia

Repeated “warning hemorrhages “

often occurring over a period of

weeks

No abdominal pain

Abdominal

examination

Local uterine tenderness,

hypertonic uterus in a concealed

abruption

Patients usually in labor

Presenting part not engaged

Fetal parts maybe difficult to

palpate

FHT often absent

Normal uterine tone and usually

no tenderness

Patient rarely in labor

Presenting part above brim,

malpresentation frequently found

Fetal parts usually palpable

FHT present

Ancillary Aids Placenta demonstrated in the

upper uterine segment

Placenta demonstrated in the

lower uterine segment

Vaginal examination NO placenta within 5 cm of the

cervical os

Placenta implanted in the Lower

uterine segment

Management No place in expectant

management

< 36 week, bleeding stopped,

expectant management is

indicated