placenta previa edited

8/9/2019 Placenta Previa Edited

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Placenta previaPlacenta previa


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The placenta provides the fetus with oxygen and nutrients and

takes away waste such as carbon dioxide via the umbilical cord.


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Definition

Placenta previa is a condition that may occur

during pregnancy when the placenta attached

wholly or partly to the lower segment of the

uterus and obstructs the cervical opening to the

vagina (birth canal).

Placenta praevia occurs in 0.5% of all

pregnancies and accounts for 20% of all cases

of antepartum haemorrage. First episode of bleeding occurs after 36th

gestational week in 60% of cases,between 32nd

and 36th week in 30% and before 32nd week in

10%.


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IncidenceIncidence

The incidence of placenta previa is

approximately 1 out of 200 births.

increases with eachpregnancy, and it isestimated that the incidence in women

who have had 6 or more previous

deliveries may be as high as 1 in 20 births.

doubled in multiple pregnancy (such as

twins and triplets).


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EtiologyEtiology

Endometrium factors:

a scarred endometrium (lining of the uterus)

from previous trauma, surgery, or infection. Curretage for several times

an abnormal uterus

Placental factors

Large

abnormal formation of the placenta.

Development retardation of fertilized egg


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Risk factorsRisk factors

multiparity (previous deliveries).

multiple pregnancy.

previous myomectomy (removal of uterinefibroids through an incision in the uterus)

previous C-section (if the scar is low and

close to the vaginal cervix region).

smoking

Abortion.


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classificationclassification

Complete placenta previa

Partial placenta previa

Marginal placenta previa

Low lying placenta


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Complete (total) placenta previa: entire cervical os iscovered by placenta.

Partial placenta previa:the margin of the placenta

extends across but not all of the internal os.

Marginal:edge of the placenta lies adjacent to theinternal os

Low lying placenta:placenta is located near but notdirectly adjacent to the internal os.


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Clinical findingsClinical findings

Symptoms

Spotting during the first and second trimesters

Sudden, painless, and profuse vaginalbleeding in pregnancy during the third

trimester (usually after 28 weeks)

--Bleeding may not occur until after labor starts

in some cases--Anemia,shock


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Signs

The uterus is usually soft and relaxed.

There is no tenderness and fetal heart sounds

present.

The fetal position is oblique ( // ) or

transverse ( == ) in about 15% ofcases.Because placenta occupies the lower

segment and prevent the head entering pelvis.

Fetal distress is not usually present unless

vaginal blood loss has been heavy enough toinduce maternal shock, placenta abruptio, or

a cord accident occurs.

No digital examination


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CautionCautionDouble setup vaginal examination

No digital vaginal or rectal examinationis performed in case of placenta previa .

Only as a final and definitive event andonly under conditions of double set up.

This procedure involves careful evaluation

of the cervix in the operation room withfull preparations for rapid cesarean section.


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DiagnosisDiagnosis

History

Symptom

Vaginal examination Ultrasonography

Placenta and membrane examination after

delivery


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Painless vaginal bleed:

First bleeding episode is 29~30 weeks

Bleeding is caused by separation of part of the

placenta from the lower uterine segment and

cervix,possibly in response to mild uterine

contractions.


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Accessory examinationsAccessory examinations

Ultrasonography: Accuracy 95%

34th week

If the placenta lies in the posterior portion of the lower uterinesegment,its exact relation with the internal os may be more

difficult to ascertain. In these instances,transvaginal

ultrasonography is useful adjunct to the transabdominal

approach.

Postpartum examination of placenta andmembrane

7cm


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Differential diagnosis

Placental abruption

Vessel(vasa) Previa

Cervical polypus

Cervical erosion Cervical carcinoma


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ComplicationsComplications

Maternal complications majorhemorrhage, shock, and death.

Implanted placenta

Anemia and infection

Fetal complications Prematurity (infant is less than 36 weeks gestation) is

responsible for about 60% of infant deaths secondaryto placenta previa.

F

etal blood loss orh

emorrhage may occur because ofthe placenta tearing away from the uterine wall during

labor. It may also occur with entry into the uterusduring a C-section delivery.


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TreatmentTreatment

The course of treatment depends on

the amount ofabnormal uterine bleeding

whether t

he fetus is developed enoug

htosurvive outside the uterus

the amount of placenta over the cervix

the position of the fetus

the parity (number of previous births) for themother

the presence or absence of labor.


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Before 37 weeks of gestation any patient with antepartum haemorrage

secondary to placenta preavia should be managed conservatively,provided

the bleeding is not profuse or prolonged.

After admission,she should be kept nil orally and rested in bed.

If patient bleeds more than 6 pads within 24hrs or develops uterine

contraction,c-section should be done.

If bleeding subsides,she should be kept in hospital and managed

conservatively.

She should be given Iron and folic Acid supplements and Hb conc should be

done weekly to ensure she does not develop anaemia.

Ultrasound should be done fortnightly to check growth of fetus and placental

migration.

An elective c-section is done at 38 to 39 weeks of gestation if patient does

not bleed further .

If antepartum haemorrage occurs any time after 37weeks of gestation,an

emergency C-section should be done.


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Early in pregnancy,

transfusions may be given to replace

maternal blood loss.

Medications may be given to prevent

premature labor, prolonging pregnancy to at

least 36 weeks.


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Cesarean section is the method for delivery. It has

proven to be the most important factor in reducing

maternal and infant death rates.

The main risk with a vaginal delivery with a praevia is

that as you are trying to bring down the head or a leg,you might separate more of the placenta and increase

the bleeding.


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Immediate delivery

Indications:

When the bleeding is profuse and life is threatening , no

matter the fetus is mature or unmature ,alive or dead.

If bleeding continues but is neither profuse nor

life th

reatening and th

e gestation is more th

an34 weeks.


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Expectations (prognosis)Expectations (prognosis)

The maternal prognosis (probable

outcome) is excellent when managed

appropriately. This is done by hospitalizing

those at risk who are exhibiting signs and

symptoms, and by performing C-section

delivery.


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placenta previa edited

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