Outcome analysis of 34 pregnancies in women with essential thrombocythemia.

Objective: To evaluate the clinical impact of essential thrombocythemia on the outcome of pregnancy or vice versa.

Design: A retrospective study.

Setting: All patients were seen at our tertiary referral center, and most were followed up by their local physicians.

Patients: From 1975 through 1991, 73 women younger than 50 years with essential thrombocythemia were seen at our institution. All patients were followed up through patient or physician contact. A detailed obstetric history, including peripartum complications and management, was obtained.

Results: Among the 73 women, 34 pregnancies occurred in 18 patients. There were two uncomplicated elective abortions and one ectopic pregnancy. Of the 31 other pregnancies, 17 (55%) resulted in live birth and 14 (45%) ended in spontaneous abortion (all but two in the first trimester). Abortion could not be predicted from history of disease complications before or during pregnancy or by the presence or absence of specific therapy during pregnancy. Preconception platelet counts in women whose pregnancies resulted in live birth were similar to those of women whose pregnancies ended in abortion. Other complications during pregnancy were rare.

Conclusions: Patients with essential thrombocythemia have an increased risk of first-trimester abortion, which does not appear to be predictable or influenced by therapy. However, most patients are able to carry pregnancies to term with little or no risk of obstetric or thrombohemorrhagic complications during or after delivery. Overall, specific therapy during pregnancy did not appear to modify the clinical outcome, and the benefit of platelet apheresis during delivery could not be substantiated.