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Care of the Woman and Fetus at Risk Due to Placental Problems

Most common types of placental problems:

-abruptio plantae

-placenta previa

-abnormalities in placental formation and structure

Abruption Placentae

-premature separation of a normally implanted placenta from the uterine wall

-catastrophic event due to the severe resulting hemorrhage

-occurs 1 in 100 births and more frequently in pregnancies complicated by hypertension and cocaine

abuse

-cause is largely unknown

Theories:

-decreased blood flow to the placenta through the sinuses during the last trimester

-excessive intrauterine pressure caused by hydamnios or multiple-gestation pregnancy, maternal

hypertension, cigarette smoking, alcohol ingestion, increased maternal age and parity, trauma, domestic

violence and abuse, nonvertex presentation, and sudden changes in uterine pressure ( as withamniotomy) as contributing factors.

Three types of Abruptio Placentae

-Marginal

-placenta separates from its edges

-blood passes between the fetal membranes and the uterine wall, and the blood escapes

vaginally

-also called marginal sinus rupture

-Central

-placenta separates centrally

-blood is trapped between the placenta and the uterine wall

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-results in concealed bleeding

Complete

-massive vaginal bleeding is seen in the presence of total separation

Differential Signs and Symptoms of Placenta Previa and Abruptio Placentae

Placenta Previa Abruptio Placentae

Onset Quiet and sneaky Sudden and stormy

Bleeding External External or Concealed

Color of blood Bright red Dark venous

Anemia =Blood loss >apparent blood loss

Shock =Blood loss >apparent blood loss

Toxemia Absent May be present

Pain Only labor Severe and steady

Uterine tenderness Absent Present

Uterine tone Soft and relaxed Firm to stony hardUterine contour Normal May enlarge and change shape

Fetal heart tones Usually present Present or absent

Engagement Absent May be present

Presentation May be abnormal No relationship

Couvelaire uterus

-in severe cases of central abruption placentae, the blood invades the myometrial tissues between the

muscle fibers

-it accounts for the uterine irritability that is a significant sign of abruption placentae

-if hemorrhage continues, eventually the uterus turns entirely blue, because the muscle fibers are filled

with blood.

-after birth the uterus contracts poorly.

-it necessitates hysterectomy

Maternal implications

-damage to the uterine wall and retroplacental clotting with central abruption

-large amounts of thromboplastin are released into the maternal blood supply

-this triggers the development of DIC and resultant hypofibrogenemia.

-fibrinogen levels, which are ordinarily elevated in pregnancy, may drop to a point at which blood will no

longer coagulate.

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-moderate to severe bleeding can occur which may lead to hemorrhagic shock.

Fetal-Neonatal Implications

-ranges from 25-35 % perinatal mortality with abruption placenta

-in severe cases 100% mortality rate

-in less severe separations, fetal outcome depends on the level of maturity and the length of time to

deliver.

-the rate of survival is highest in foetuses delivered within 20 minutes of initial separation of the

placenta.

-the most serious complications in the newborn arises from preterm labor, anemia, hypoxia.

-if fetal hypoxia progresses unchecked, irreversible brain damage or fetal demise may result.

Clinical therapy

-coagulation tests are imperative

-after establishing diagnosis, immediate priorities are:

-maintaining the cardiovascular status of the mother

-developing plan to deliver the fetus. In many circumstances caesarean birth will be the safest

option

-If separation is mild and the pregnancy is near term, labor may be induced and the fetus born vaginally

with as little trauma as possible.

-If rupture of membranes and Pitocin infusion by pump do not initiate labor, caesarean is required.

-in cases of moderate to severe placental separation, a caesarean birth is done after the treatment of

hypofibrinogenemia by IV infusion of cryoprecipitate or plasma.

-hypovolemia that accompanies abruption placenta is life threatening.

-if fetus is alive=caesarean birth

-if stillborn=vaginal delivery is preferable if bleeding has stabilized, unless maternal shock from

hemorrhage has already occurred.

-CVP monitoring may be needed to evaluate IVF replacemtent. Goal is 10 cmwater.

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Nursing Care Management

-electronic monitoring of the uterine contractions and resting tone between contractions is monitored

to know the labor pattern and evaluate the effectiveness oof Pitocin induction.

-resting tone is frequently increased in abruption placentae

-abdominal girth measurements may be ordered hourly and are obtained by placing a tape measure

around the maternal abdomen at the level of the umbilicus.

-another method is by placing a mark at the top of the uterine fundus, the distance from the symphisis

pubis to the mark.

-overdistention of the uterus can result to a ruptured uterus.

Placenta Previa

-the placenta is implanted in the lower uterine segment rather than the upper portion of the uterus.

-may be on the lower segment or over the internal cervical os.

-Placental bleeding occurs when placental villi are torn from the uterine wall but initially it may be either

scanty or profuse.

-Bleeding depends on the number of sinuses exposed.

-Placenta previa is categorized as being total (the internal os is completely covered), partial (the internal

os is partially covered), marginal (the edge of the placenta is covered) or low lying (the placenta is

implanted on the lower uterine segment in close proximity to but not covering the internal os).

-cause is unknown

-it occurs 4 per 1000 births.

-women with previous history of placenta previa have an increased risk of developing another in future

pregnancies.

-other factors includes multiparity, increasing age, placenta acrreta, defective development of blood

vessels in the decidua, a large placenta, smoking and cocaine use in pregnancy, previous caesareansection or abortion, male fetus.

Fetal-Neonatal Implications

-prognosis depends on the extent of placenta previa

-in marginal previa or low lying placenta, the woman may be allowed to labor.

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-changes in the FHR and meconium staining of the amniotic fluid may be apparent.

-in a profuse bleeding episode, the fetus is compromised and suffers some hypoxia.

-FHR monitoring is imperative particularly if a vaginal birth is anticipated.

-if nonreassuring fetal status occurs, caesarean birth is indicated.

-Complete or Partial previa will undergo a caesarean birth since the risk of intrapartum haemorrhage is

high.

-blood sampling is done after delivery in order to determine whether intrauterine bleeding caused

anemia to the newborn.

Clinical Therapy

-indirect diagnosis is made by localizing the placenta through tests that require no vaginal examinations,

such as ultrasound scan.

-vaginal examination should never be done on a women with bleeding since the examiner might

perforate the placenta if cervical dilation has occurred.

Diagnosis by ultrasound

Gestation < 37 weeks