Myeloproliferative Disorders

Key points

  • Historical literature suggests myeloproliferative disorders are associated with increased maternal and fetal morbidity and mortality.
  • There have been no prospective national studies to estimate the incidence or outcomes of myeloproliferative disorders, persistent thrombocytosis or erythrocytosis in pregnancy.
  • This study of myeloproliferative disorders, persistent thrombocytosis or erythrocytosis in pregnancy will investigate the incidence, management and outcomes for mother and infant.

Surveillance Period

January 2010 – December 2012

Background

The aim of the proposed study is to use the UK Obstetric Surveillance System to describe the epidemiology of myeloproliferative disorders (MPDs), persistently increased number of platelets or red cells in pregnancy. The Myeloproliferative disorders (MPDs) are clonal haematological malignancies characterised by over production of mature blood cells and a chronic clinical course. They include polycythaemia vera (PV), primary myelofibrosis (PMF) and essential thrombocythaemia (ET).

The most extensive literature for epidemiology and outcome of pregnancy exists for ET with approximately 461 pregnancies reported[1]; for PV and PMF the literature is more limited, reporting mostly single centre studies. The outcome for pregnancy in ET appears to be relatively poor with a successful live birth rate of 50-57%. Complications are more prevalent than in haematologically normal controls: first trimester loss is reported in 26-36%; late pregnancy loss in 5-9.6%, IUGR in 4-5.1%, preterm delivery in 5.6-8%, and placental abruption in 2.8%. For PV the limited literature suggests that the successful pregnancy rate is 57% with a significant risk of first trimester loss, intrauterine growth retardation and late pregnancy loss or pre-term delivery. In PV maternal morbidity due to thrombotic and bleeding problems were notable with 3 cases of pre-eclampsia, 1 ante-partum and 2 post partum pulmonary emboli, and 1 large post partum haemorrhage[2]. In PMF the data suggest a high 50% risk of fetal loss but an equal 50% chance of live birth; no maternal complications of thrombosis or disease progression were noted[3].

MPD especially PV and PMF in pregnancy are thus under-researched, our understanding of them is poor and any interventions used in current clinical practice are rarely based on robust evidence. Prospective data collection on known and occult MPDs in pregnancy using UKOSS will provide valuable information into the epidemiology and complications of MPD in pregnancy.

Objectives

  • To use the UK Obstetric Surveillance System to describe the epidemiology of myeloproliferative disorders in the UK.

Research questions

  • What is the current number of pregnant women with a diagnosis of a myeloproliferative disorder, persistently increased number of platelets (thrombocytosis) or red cells (erythrocytosis) in pregnancy in the UK per 10,000 pregnant women per year?
  • How are pregnant women with a diagnosis of a myeloproliferative disorder, persistently increased number of platelets or red cells managed in pregnancy?
  • What is the outcome of pregnancies in women with a diagnosis of a myeloproliferative disorder, persistently increased number of platelets or red cells for the mother and infant?

Case definition

All pregnant women in the UK identified as having:

EITHER a myeloproliferative disorder (essential thrombocythaemia, polycythaemia vera, myelofibrosis), diagnosed by a consultant haematologist according to WHO guidelines

OR a thrombocytosis (platelet count persistently greater than 600 x109/l)

OR an erythrocytosis (haemoglobin persistently greater than 16.5g/dl).

Funding

Guy’s and St Thomas’ Charity

Ethics committee approval

The study has been approved by the National Research Ethics Service (study ref 09/H0802/124).

Investigators

Sue Robinson, Claire Harrison, Susan Bewley, Gabriella Gray, Guy’s and St Thomas’ Hospital

Further reading

  1. Griesshammer M, Struve S, Harrison CN. Essential thrombocythemia/polycythemia vera and pregnancy: the need for an observational study in Europe. Semin.Thromb.Hemost. 2006;32:422-429.
  2. Elliott MA, Tefferi A. Thrombocythaemia and pregnancy. Best Pract Res Clin Haematol. 2003;16:227-242.

Download the Data Collection Form (DCF)

UKOSS Myeloproliferative Disorders Form

References

  1. ^ Barbui T, Finazzi G. Myeloproliferative Disease in Pregnancy and Other Management Issues. Hematology 2006;2006:246-252.
  2. ^ Robinson S, Bewley S, Hunt BJ, Radia DH, Harrison CN. The management and outcome of 18 pregnancies in women with polycythemia vera. Haematologica 2005;90:1477-1483.
  3. ^ Tulpule,S., Bewley,S., Robinson,S.E., Radia,D., Nelson-Piercy,C., & Harrison,C.N. (2008). The management and outcome of four pregnancies in women with idiopathic myelofibrosis. Br J Haematol, 142, 480-482.