Gestational thrombocytopenia

Gestational thrombocytopenia (GT) refers to a platelet count of < 150,000/µl occurring for the first time during pregnancy that is not due to another condition (Cines 2017).

Gestational thrombocytopenia occurs in approximately 8% of all pregnant women (Herold 2022). It is the most common cause of thrombocytopenia occurring in pregnancy, accounting for 75% of all cases (Cines 2017).

The causes of thrombocytopenia occurring during pregnancy may be benign, as is the case with gestational thrombocytopenia induced by increased platelet turnover or hemodilution (Herold 2022), but may also be signs of life-threatening disease (Pishko 2022).

GT occurs preferentially in multiple pregnancy (Stepan 2022).

The exact pathophysiology of GT is not yet known. During pregnancy, there is a physiological decrease in platelet count from the 1st trimester onwards, which is lowest at the time of delivery. This is due to hemodilution as a result of increased plasma volume and sequestration of platelets in the spleen (Pishko 2022).

Klamroth (2010) suspects immunological processes in the sense of a transient immune thrombocytopenia as the most likely cause of GT.

1st trimester:

In the 1st trimester, GT occurs very rarely. The platelet count is usually < 150,000/µl. The most common cause of thrombocytopenia during this period is idiopathic thrombocytopenia (ITP) (Pishko 2022).

2nd trimester:

Starting in the 2nd trimester, there is a progressive decrease in platelets in GT (Stepan 2022). At platelet counts ≥ 100,000/µl, this is 1st caused by GT and second most by ITP. With platelet counts < 100,000 / µl during this period, the most common cause is found to be ITP and the second most common is preeclampsia (Pishko 2022).

3rd trimester:

In the 3rd trimester, if thrombocytopenia is ≥ 80,000 / µl, the 1st most common cause is found to be GT and the 2nd most common cause is preeclampsia.

If the platelet count is < 80,000 / µl, the cause is preeclampsia in the first place and ITP in the 2nd place (Pishko 2022).

The disease is asymptomatic (Herold 2022). There is - despite the thrombocytopenia - no increased risk of bleeding for mother and child (Stepan 2022).

There is currently no test to confirm the diagnosis of GT (Kranke 2018).

Diagnostic clarification of thrombocytopenia occurring during pregnancy should be performed if it:

- has already occurred once before

- in the case of platelet counts < 80,000 / µl.

- a tendency to bleed in the patient's own or family history, irrespective of the platelet count and gestational age

- Manifests in the 1st or 2nd trimester (Bergmann 2015).

The diagnosis of GT is always a diagnosis of exclusion and is made by clinical criteria:

- mild thrombocytopenia

- in 90 % with values of ≥ 100,000 / µl

- preferentially occurring in the last trimester

- without increased bleeding tendency (Sucker 2017).

The platelet count is decreased, but usually remains > 100,000 / µl (Herold 2022). Only about 1% of pregnant women have a platelet count < 100,000/µl at birth and 0.1% have a platelet count < 80,000/µl (Pishko 2022).

A peripheral blood smear should always be examined for any pseudothrombocytopenia or morphologic abnormalities. In addition, liver and kidney function should be determined (Pishko 2022).

- immune thrombocytopenia (ITP)

- thrombotic thrombocytopenic purpura (TTP)

- disseminated intravascular coagulation (DIC)

- preeclampsia (Kasper 2015)

- complement-mediated thrombotic microangiopathy

- thrombotic microangiopathy (TMA)

- hereditary thrombocytopenia (Pishko 2022)

In particular, the severity of thrombocytopenia and the trimester of onset play a major role in ruling out differential diagnostic disorders (Pishko 2022).

Therapy is not necessary in GT because thrombocytopenia is self-limited and disappears at the latest approx. 2 months after partum (Herold 2022).

In severe cases, corticosteroids or immunoglobulins were administered in studies. However, this did not improve the platelet count (Stepan 2022).

There is no increased risk of bleeding during delivery. Up to a platelet value of 50,000 / µl, any form of delivery is possible. No thrombocytopenia has been observed so far in the newborn of mothers with GT (Klamroth 2010).

Postpartum, regular checks of platelet counts are recommended in the mother to detect persistent thrombocytopenia early (Stepan 2022).

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