Thrombocytopeny in Pregnancy
1-Gestetional Thrombocytopenia.
2- ITP during pregnancy.
3- Preeclampsia.
4- TTP-HUS Associated with pregnancy.
GESTATIONAL THROMBOCYTOPENIA
Incidental thrombocytopenia of pregnancy, also
termed gestational thrombocytopenia, is defined by
the following five criteria .
1 - Mild and asymptomatic thrombocytopenia.
2 - No past history of thrombocytopenia (except
possibly during a previous pregnancy).
3 - Occurrence during late gestation.
4 - No association with fetal thrombocytopenia.
5 - Spontaneous resolution after delivery.
ITP DURING PREGNANCY AND DELIVERY
The diagnosis and overall treatment of ITP are described separately.
the distinction from gestational thrombocytopenia is empirical.
Early in pregnancy the management of ITP is the same as if the
patient were not pregnant, using prednisone as initial therapy to
treat patients whose platelet counts are less than 30,000 to
50,000/µL, depending upon symptoms.
Splenectomy should be deferred if possible, because the severity
of thrombocytopenia may spontaneously improve after delivery [15].
Furthermore, splenectomy may increase the risk of fetal death and
premature labor in early pregnancy and uterine enlargement
presents technical problems in performing a splenectomy later
during pregnancy.
Intravenous immune globulin (IVIG) is an alternative
temporary therapy that may help to delay splenectomy, although
splenectomy remains the most effective treatment for severe,
symptomatic ITP.
The greatest concern for ITP during pregnancy comes as term
approaches and the risks of thrombocytopenia in the newborn infant
must be considered.
The severity of ITP in the mother appears to correlate with the
risk for thrombocytopenia in the infant. Neonatal
thrombocytopenia may be predicted by the following
situations:
-The mother has had a splenectomy .
-The mother's platelet count has been less than
50,000/µL at some time during the pregnancy.
-An older sibling has had neonatal thrombocytopenia.
In one study of sixty-four pregnant women with known chronic ITP, severe
neonatal thrombocytopenia was only observed in those women with both severe
pregnancy-associated thrombocytopenia and splenectomy (57 percent), versus zero
percent in mothers without these antecedents .
-In a study of 31 pregnancies in 25 women with ITP, no
significant association was found between the rate of
intracranial hemorrhage and delivery mode for moderately
and severely thrombocytopenic neonates taken together as a
group, or for those with severe thrombocytopenia .
Counseling of pregnant women with ITP
These observations provide support for counseling of women
with ITP who are pregnant, or who anticipate pregnancy:
Although thrombocytopenia may occur in the infant, it is
uncommon. Ninety percent of infants will have safe
(>50,000/microliter) or normal platelet counts.
Even when severe thrombocytopenia occurs, bleeding problems are
almost always mild and can be effectively treated.
In some infants who have had serious bleeding, such as
intracranial hemorrhage, the bleeding occurred when the platelet
count decreased after birth. These bleeding complications are
preventable with careful monitoring of platelet counts after birth
and prompt treatment of thrombocytopenia.
Since intracranial hemorrhage is very rare in infants
born to mothers with ITP, the occurrences should be
investigated for other causes of thrombocytopenia, such as
fetal-maternal incompatibility for platelet antigens.
PREECLAMPSIA
Preeclampsia refers to the otherwise unexplained and gradual
development of hypertension, proteinuria, and edema in
pregnancy. These findings typically become apparent in the
latter part of the third trimester and progress until delivery
In some patients, however, symptoms begin in the latter half
of the second trimester, while other women have an onset
that is delayed until delivery or even the early postpartum
period.
The prevalence is estimated incidence is 5 to 10 percent of all pregnancies (3 to 4
percent in the United States), with a higher risk in primiparas under the age of 20
. Eclampsia is generally defined as the occurrence of seizures
in a preeclamptic woman that cannot be attributed to another
cause; it is usually, but not always, preceded by hypertension
and proteinuria . Its incidence is about 0.05 percent in developed
countries but as high as 1 percent in underdeveloped countries.
Platelet counts are lower in preeclamptic women than in women with
uncomplicated pregnancies , with an estimated incidence of thrombocytopenia of
approximately 15 percent. If 4 percent of pregnant women develop preeclampsia
in the United States and 15 percent become thrombocytopenic, then
thrombocytopenia due to preeclampsia will occur in about 6 of every 1000 deliv e
Differential diagnosis
The systemic signs of preeclampsia typically resolve within
hours to days following delivery. In some patients, the
hematologic manifestations of preeclampsia first develop in the
immediate postpartum period.
In severe preeclampsia (including HELLP syndrome) and
eclampsia, thrombocytopenia and microangiopathic hemolytic
anemia can combine with seizures and other organ
dysfunction to produce a disorder that may be clinically
indistinguishable from TTP-HUS. The main findings pointing
toward TTP-HUS in such patients are the absence of DIC and
progression of the hematologic abnormalities for more than three
days after delivery.
Symptoms and signs of liver disease may predominate in the HELLP
syndrome, which may cause confusion with acute fatty liver of
pregnancy. The latter disorder is not typically associated with
thrombocytopenia unless there is supervening DIC. the HELLP
syndrome and acute fatty liver of pregnancy may be
pathogenetically related although phenotypically different.
Treatment
Delivering the fetus is the most effective method of treating
preeclampsia, eclampsia, and the HELLP syndrome. In most
patients with preeclampsia, hematologic recovery begins promptly
following delivery. However, the nadir of thrombocytopenia and the
peak serum LDH levels may occur postpartum . Recovery within
three days following delivery is consistent with the diagnosis of
preeclampsia; more prolonged, severe thrombocytopenia and
hemolysis becomes indistinguishable from TTP-HUS.
Infants born to mothers with preeclampsia are not at increased risk
for thrombocytopenia.
For patients with severe thrombocytopenia and microangiopathic
hemolytic anemia, plasma exchange may be indicated if the fetus
cannot be delivered or if improvement does not follow delivery. The
third postpartum day is often considered the limit for only
supportive therapy or corticosteroids without plasma exchange in
anticipation of a spontaneous recovery
TTP-HUS ASSOCIATED WITH PREGNANCY
The incidence of TTP-HUS among all pregnancies is only 1 in
25,000. TTP-HUS that initially occurred in nonpregnant
women has relapsed during a subsequent pregnancy and
recurrent TTP-HUS has developed during successive
pregnancies.
There are no pathognomonic findings, rather the diagnosis is
based upon the clinician's judgment after considering the
history, physical examination, and laboratory findings.
The time of onset of TTP-HUS in pregnancy is
variable. In one report of 13 pregnancies
complicated by TTP-HUS, three developed before
midpregnancy, eight peripartum (a time of possible
confusion with preeclampsia, as mentioned above),
and two several weeks postpartum
The primary therapy for TTP-HUS related to
pregnancy is plasma exchange as it is in
nonpregnant patients .
One report, for example, treated 11 women with TTP-HUS
with plasma infusion with or without plasma exchange . Two
women died, four had chronic renal insufficiency (one with a
residual neurologic deficit), and five recovered without
Renal failure requires supportive
care with dialysis and transfusion, as needed.
significant residua.
If the disease is severe and the fetus is viable, delivery should
be induced since this will resolve preeclampsia which, as
noted above, may be confused with TTP-HUS.
delivery does not generally cause resolution of TTPHUS , there is anecdotal evidence that it may do so in
selected patients . However, termination of the pregnancy is
usually not required
There has been no report of transmission of TTP to the infant.
intrauterine fetal death may occur due to placental infarction caused
by thrombosis of the decidual arterioles conditions
HELLP SYNDROME
HELLP develops in approximately 10 to 20
percent of women with preeclampsia.
The majority of cases are diagnosed
between 22 and 36 weeks of gestation.
An illustrative series included 437 women who had
442 pregnancies complicated by the HELLP
syndrome, 70 percent occurred prior to delivery. Of
these patients:
Approximately 80 percent of cases were
diagnosed prior to 37 weeks of gestation.
Less than 3 percent occurred between 17
and 20 weeks of gestation.
Clinical manifestations and diagnosis
The diagnosis of HELLP syndrome is based upon the presence
of the characteristic laboratory findings in patients of
appropriate gestational age. Imaging tests, particularly CT or
MRI scanning, are useful when complications such as hepatic
infarction, hematoma, or rupture are suspected . the
diagnosis was established by the presence of preeclampsia
and the following criteria:
1- Microangiopathic hemolytic anemia with
characteristic schistocytes on blood smear.
2-Platelet count <100,000 cells/µL
3-Serum lactate dehydrogenase >600 IU/L or total
bilirubin >1.2 mg/dL
4-Serum aspartate aminotransferase (AST)>70 IU/L
5-Signs of disseminated intravascular coagulation
occur in approximately 20 percent of patients.