An unusual case of gestational thrombocytopenia: case report and review of the literature

Abstract

Introduction Thrombocytopenia, or a low blood platelet count, is encountered in 7–8% of all pregnancies1. It is the second most common blood disorder in pregnancy2,3. The first blood disorder is anaemia3. Platelets are non-nucleated cells derived from megakaryocytes in the bone marrow and normally live in the peripheral circulation for as long as 10 days. Platelets play a critical initiating role in haemostatic system1,4. The normal range of platelets in non-pregnant women is 150 000– 400 000/μL. Average platelet count in pregnancy is decreased. Change in platelet count is due to haemodilution, increased platelet consumption and increased platelet aggregation driven by increased levels of thromboxane A2. Thrombocytopenia can be defined as platelet count less than 150 000/μL or platelet count below the 2.5th percentile for pregnant patients (116 000/μL)1. Classification of thrombocytopenia in pregnancy is arbitary and not necessarily clinically relevant. Mild thrombocytopenia is 100 000– 150 000/μL, moderate thrombocytopenia is 50 000–100 000/μL and severe thrombocytopenia is less than 50 000/μL. The pathophysiology of gestational thrombocytopenia (GT) is unknown. It usually develops in the third trimester, detected incidentally, pati ents are asymptomatic with no prepregnancy history of low platelets or abnormal bleeding, it is mild thrombocytopenia (counts more than 70 000/μL)5–9. GT accounts for almost threefourths of all cases of thrombocytopenia2,10. Mode of delivery is determined by obstetric/maternal indications. Platelet counts normalize within 2–12 weeks following delivery10–12. No pathological significance for the mother or foetus is noted. No risk for foetal haemorrhage or bleeding complications is observed13–17. A low platelet count can also be associated with preeclampsia, HELLP syndrome or idiopathic thrombocytopenic purpura (ITP)18–23. The differential diagnosis between mild ITP and GT is very difficult during pregnancy5,19. ITP accounts for only approximately one case of thrombocytopenia per 1000 pregnancies and 5% of cases of pregnancy-associated thrombocytopenia, it is the most common cause of significant thrombocytopenia in the first trimester24–27. Women with ITP often have a history of bleeding complications and have thrombocytopenia on a prepregnancy platelet count16,28. We present this rare case of GT in a pregnant 30-year-old woman.