Pregnancy loss, which occurs in approximately 10 to 15% of all gestations, has been linked to many blood-related changes which take place during pregnancy. Some of these changes have proven to lead to life-threatening conditions, particularly in patients who already present with hematologic conditions.

This review aims to point out the most prevalent hematological disorders found in clinical practice that may favor the event of a single or of multiple spontaneous abortions in women, as well as to highlight the need for a prompt diagnosis and early treatment in these scenarios, as to avoid maternal complications and pregnancy loss.

This study is a literature review. We searched the PubMed/Medline database to identify studies related to pregnancy loss in patients with various hematological disorders. The primary search was conducted using the terms: “Hematological” and “Miscarriage”. We included 12 articles in the English language, published from 2013 to 2024.

The most common hemostasis-related cause of Recurrent Pregnancy Loss (RPL) is antiphospholipid syndrome (APLS), accounting for about 8 to 42 percent of patients with RPL. APLS causes an increased risk of thrombosis and placental insufficiency, causing the miscarriages. Thrombophilia is a condition in which the blood has a tendency to form clots, which can predispose women to RPL due to placental thrombosis and impaired blood flow. Pregnant women with Von Willebrand Disease are especially susceptible to having significant bleeding complications. Thrombocytopenia is another prevalent bleeding problem during pregnancy, affecting approximately 10% of all pregnancies. The American Society of Hematology recommends that treatment should be initiated for platelet counts below 30,000/mm3 or in cases of bleeding within the second or third trimesters of pregnancy. A less common, yet worth mentioning, disorder that influences the incidence of miscarriages is Sickle Cell Disease (SCD), a disease which causes reduced oxygen delivery to the placenta and fetal tissues, increasing the risk of adverse outcomes during gestation. Furthermore, other hemoglobinopathies, such as Thalassemia, may lead to anemia and intrauterine growth restriction due to inadequate oxygen supply.

Hematological disorders can significantly contribute to pregnancy loss through a wide spectrum of mechanisms, ranging from abnormal clotting disorders to excessive bleeding. This depicts the fact that each patient must be individually evaluated for a broader understanding and safer conduct in clinical practice. Finally, of utmost importance, if properly screened, the cause for recurrent pregnancy losses (RPL) can be found in almost all women. The main importance of a thorough evaluation is that, if a cause for the RPL is found, most women will be able to achieve normal-term delivery.

Pregnancy can aid to cause and/or exacerbate underlying hematologic disorders, as well as predispose to life-threatening hematologic emergencies. Therefore, it's essential that women receive specialized care during pregnancy to optimize its outcomes and minimize any risks related to hematologic problems, which commonly require comanagement by obstetrics, hematology, and other subspecialties.