Essential thrombocythemia in pregnancy: platelet count and pregnancy outcome.

We report our experience of 4 successful pregnancies (including a pair of twins) in 3 women who have essential thrombocythemia (ET). All of the patients had a significant fall in platelet count (> 20% of non-pregnant state) during the course of the pregnancy. A review of the literature and our own experience suggests that the degree of platelet count reduction may be correlated with pregnancy outcome. Close monitoring of the platelet count is useful in the management of these cases.