Effect of Pregnancy in Women with a History of Primary Immune Thrombocytopenia Considered As Cured

Immune thrombocytopenia (ITP) is an autoimmune disease that occurs in young women. Pregnancy is a well-known risk factor for developing newly diagnosed ITP as well as for inducing disease flares in patients with current ITP. However, the impact of pregnancy in women with an old history of ITP, considered as cured, has not been assessed. The aim of this study was to describe the course of ITP in pregnant women with an ITP in complete remission (platelets count >100x10⁹/L and absence of bleeding symptoms) for at least 5 years without any ITP treatment.

We retrospectively selected all pregnant women with delivery at Toulouse University Hospital, South of France, between 2010 and 2015 with a hospital discharge code of ITP (international classification of diseases; version 10 code D69.3). This code has a sensitivity of 81.2% and a positive predictive value of 89.8% in this database. All medical charts were reviewed to confirm the diagnosis of ITP. We included adult women (≥18 years) with a diagnosis of primary ITP according to French guidelines (platelet count <150 x 10⁹ /L and exclusion of other causes of thrombocytopenia, especially other causes of thrombocytopenia during pregnancy) in complete remission for at least 5 years.

We identified 50 pregnancies in 39 ITP patients during the study period. Eleven pregnancies occurred in 10 patients in long-term complete remission of ITP at the time of pregnancy onset. Baseline characteristics were: median age at ITP diagnosis: 21 years (range: 4-29); median age at pregnancy onset:32 years (range: 26-34; history of ITP during a previous pregnancy: 1; history of bleeding: 4 (36.4%); previous treatment for ITP: 8 (72.7%), corticosteroids-CS (5), CS and intravenously immunoglobulin-IVIg (3), splenectomy (4), dapsone (1); last median platelet count before pregnancy: 170x10⁹/L (range: 118-363).

Platelets count decreased below 100x10⁹/L in 3 pregnancies (27.2%) from the first trimester for one patient, from the second trimester for one other and from the third trimester for the last one, with a nadir of 3, 39 and 87 (x10⁹/L) respectively. One of them experienced a severe bleeding (grade 3 according to the International Working Group bleeding classification). All thrombocytopenic patients required treatment during pregnancy: CS+IVIg for 2 (one for bleeding and one to allow epidural analgesia) and IVIg for the other (to allow epidural analgesia). For these 3 women, the median platelet count at delivery was 128 (range: 38-159) and consequently only 2 of them could have epidural analgesia. No bleeding during delivery was observed. Transient thrombocytopenia occurred in 2 newborns.

Primary ITP considered as cured may relapse during pregnancy and may induce severe bleeding requiring specific treatment. A tight monitoring should be proposed to all pregnant women with a history of primary ITP, even after several years of complete remission.