Pregnancy-associated thrombocytopenia

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Classification according to ICD-10
O28.0 Abnormal haematological finding on maternal antenatal screening
D69.5 Secondary thrombocytopenia
ICD-10 online (WHO version 2019)

The pregnancy-associated thrombocytopenia (including gestational thrombocytopenia is) a change in the blood count in pregnant women with decrease in the concentration of blood platelets (thrombocytes) less than 150,000 / ul, a thrombocytopenia .

Thrombocytopenia in uncomplicated pregnancy

At the time of birth, the platelet value in 5 to 10% of pregnant women is below 150,000 / µl, which means that there is thrombocytopenia . However, if the pregnancy is uncomplicated, this is usually of no clinical significance.

In a large US cohort study with more than 15,000 pregnant women, the value usually began to decrease in the first trimester , only to reach the lowest value at the time of birth, which was below 150,000 / µl in 9.9% of women. After a mean 7.1 weeks, the value had recovered to the original level. On average, the concentration fell by 17%, reaching values ​​below 100,000 / µl in only 1% of pregnant women and below 80,000 / µl in only 0.1%, but never below 50,000 / µl. The value was consistently lower for twin births.

The mean and distribution of platelet counts over all three trimesters was increasingly lower, but the distribution remained normal , with the curve shifting to the left in the course of pregnancy. While the mean value of the platelet concentration was 273,000 / µl in a non-pregnant comparison population, it averaged 251,000 / µl in the first trimester, 230,000 / µl in the second trimester and 225,000 / µl in the third trimester and at birth (in uncomplicated pregnancies) Mean 217,000 / µl

Gestational thrombocytopenia alone does not cause symptoms. It is not associated with changes in the child's blood count and disappears again after the birth. A caesarean section is only advised against if the platelet count is below 50,000 / µl . And if the value falls below 100,000 / µl, another cause should be looked for, as this is very rare in uncomplicated pregnancies. However, most pregnancy-related complications, especially HELLP syndrome and eclampsia , lead to clear symptoms and complaints and are therefore noticeable beforehand.

Thrombocytopenia in the case of complications in pregnancy or previous illnesses

If complications occurred during pregnancy, the value was lower more frequently and thrombocytopenia at the time of birth was found in 11.9% of pregnancies with complications. In 2.3% of the women the value was below 100,000 / µl and in 1.2% below 80,000 / µl. If the HELLP syndrome was present, thrombocytopenia below 80,000 / µl was found in 28%.

Thrombocytopenia was also significantly more common in women who had a pre-existing thrombocytopenia-associated disease. Women with idiopathic thrombocytopenic purpura had values ​​below 80,000 / µl in 54%, in systemic lupus erythematosus this was the case in 6.0%, in HIV infection in 2.5% and in hepatitis in 1.4%.

The frequency of pregnancy-related autoimmune thrombocytopenia is approximately 1 in 1,000,000 pregnancies.

Another occurrence of thrombocytopenia, with repeated abortions, shows itself in the antiphospholipid syndrome . Here antibodies are directed against the body's own phospholipids, in particular against cardiolipids in the mitochondria.

root cause

Due to the increasing left shift of the normal distribution of the platelet concentration in the course of pregnancy, a dilution effect is suspected, caused by an increasingly increased plasma volume during pregnancy. Usually a third of all platelets are found temporarily in the sinusoids of the spleen . Since this becomes half the size during pregnancy ( splenomegaly ), it can also store more platelets. The placenta is also used for temporary storage and reduces the free platelet pool; in the case of multiple pregnancies, the placenta is larger.

literature

  • Bernd Pötzsch, Katharina Madlener: Coagulation Consultation: Rational diagnosis and therapy of coagulation disorders . Georg Thieme Verlag, 2002, p. 53 f. ( online )
  • Monika Barthels: The coagulation compendium: quick orientation, interpretation of findings, clinical consequences . Georg Thieme Verlag, 2012, p. 250 f. ( online )
  • Volker Kiefel: Transfusion Medicine and Immunohematology: Basics - Therapy - Methodology . Springer-Verlag, 2011, p. 93 f. ( online )
  • Bernd Pötzsch, Katharina Madlener: Hemostaseology: Basics, Diagnostics and Therapy . Springer-Verlag, 2010, p. 313 f. ( online )
  • Torsten Haferlach, Vera Ulrike Bacher, Harald Klaus Theml, Heinz Diem: Pocket Atlas Hematology: Microscopic and clinical diagnostics for the practice . Georg Thieme Verlag, 2012, p. 207 f. ( online )
  • Short textbook gynecology and obstetrics . Georg Thieme Verlag, 2015 ( online )
  • Volker Briese, Michael Bolz, Toralf Reimer: diseases in pregnancy: Manual of diagnoses from A-Z . Walter de Gruyter, 2015, p. 185 ( online )

Individual evidence

  1. ↑ ONKODIN: Oncology, Hematology - Data and Information ISSN  2193-6021 : Pregnancy and ITP - Differential Diagnoses , accessed on July 19, 2020
  2. ↑ a b c Jessica A. Reese, Jennifer D. Peck, David R. Deschamps, Jennifer J. McIntosh, Eric J. Knudtson, Deirdra R. Terrell, Sara K. Vesely, James N. George: Platelet Counts during Pregnancy New England Journal of Medicine 2018, Volume 379, Issue 1, July 5, 2018, pages 32-43, doi: 10.1056 / NEJMoa1802897

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