Peripartum Management of Women with Suspected Hereditary Thrombocytopenia.

Introduction: Hereditary macrothrombocytopenic disorders are rare syndromes characterized by mild to moderate thrombocytopenia, large platelets, and a variable bleeding phenotype. In general, the diagnosis must be made clinically and management is empiric. Because of the autosomally inherited nature of these disorders, peripartum management must take into account the risk of bleeding for both mother and baby, during the pregnancy and at delivery.

Study Purpose: To describe the peripartum management and bleeding complications in pregnant women with suspected inherited macrothrombocytopenic disorders and their children.

Study Design: We performed a retrospective review of all mothers referred to our tertiary care hospital from 2004 to 2007 for evaluation of macrothrombocytopenia in pregnancy where hereditary thrombocytopenia was suspected. The diagnosis was confirmed if at least 2 of the following clinical features were present:

1. life-long thrombocytopenia;

2. family history of thrombocytopenia that spanned at least 2 generations; and

3. the lack of a platelet count response to IVIG or corticosteroids.

Data relating to bleeding and therapies used to treat or to prevent bleeding before or during delivery for mother and child were extracted from medical charts. Blood films were reviewed with experts in morphology, and diagnostic testing was performed when possible.

Results: A total of 5 mothers and 8 babies were included. The median platelet count of mothers at delivery was 54 x 10⁹/L (range 15–83 x 10⁹/L) and the median MPV was 9.8 fL (range 7.4–11.3 fL). Of the 8 babies, 4 were thrombocytopenic with a median platelet count at birth of 50 x 10⁹/L (range 9–93 x 10⁹/L) and a median MPV of 9.4 fL (range 8.9–9.6fL). One mother and her baby had neutrophilic Dohle body inclusions, and none had skeletal, neurologic or renal abnormalities. Three mothers were previously treated with IVIG, including one who also received prednisone, with no platelet count response. During pregnancy, fetal blood sampling for platelet count measurements was not done. None of the mothers had epidural anesthesia, all delivered vaginally and 7 of 8 labours were induced. Two mothers received prophylactic tranexamic acid at the time of active labour and 1 received DDAVP. Prophylactic platelet transfusions were not given. One mother had bleeding associated with spontaneous rupture of membranes, and one had a post partum hemorrhage associated with uterine atony and vaginal laceration. The latter was repaired surgically and treated with platelet transfusions and DDAVP. None of the babies bled, but 1 was given a platelet transfusion because of severe thrombocytopenia at birth (platelet count = 9 x 10⁹/L) with persistent platelet clumping.

Conclusions: The frequency of pregnancy-related bleeding in mothers with hereditary macrothrombocytopenia was low in this cohort even in the absence of prophylaxis. There is a need for improved diagnosis and risk stratification of mothers with hereditary macrothrombocytopenia. A multicentre prospective study would assist in determining optimal peripartum management.