1. 1-Gestetional Thrombocytopenia.
‏‏‏‏Thrombocytopeny in Pregnancy
1-Gestetional Thrombocytopenia.
2- ITP during pregnancy.
3- Preeclampsia.
4- TTP-HUS Associated with pregnancy.

2. 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 Spontaneous resolution after delivery.

3. 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.

4. 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 ,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 .

5. 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.   

6. 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

7. 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.

8. 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

9. TTP-HUS ASSOCIATED WITH PREGNANCY
The incidence of TTP-HUS among all pregnancies is only 1 in 25, 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

10. 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 significant residua. Renal failure requires supportive care with dialysis and transfusion, as needed.
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 TTP-HUS , 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

13. 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.

14. 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.