Myeloproliferative neoplasms and pregnancy: Overview and practice recommendations

Abstract

Pregnancy in the context of myeloproliferative neoplasms (MPN) poses unique fetal and maternal challenges. Current literature in this regard mostly involves essential thrombocythemia (ET) and less so polycythemia vera (PV) or myelofibrosis. In ET, live birth rate is estimated at 70% with first trimester fetal loss (˜ 30%) as the major complication. Risk of pregnancy‐associated complications is higher in PV, thus mandating a more aggressive treatment approach. Herein, we appraise the relevant literature, share our own experience and propose management recommendations. Aspirin therapy may offer protection against fetal loss; however the additive benefit of systemic anticoagulation or cytoreductive therapy, in the absence of high risk disease, is unclear. We recommend cytoreductive therapy in the form of interferon alpha in all high risk and select low‐risk ET and PV patients with history of recurrent fetal loss, prominent splenomegaly or suboptimal hematocrit control with phlebotomy. In addition, all women with PV should maintain strict hematocrit control <45% with the aid of phlebotomy. Systemic anticoagulation with low molecular weight heparin is advised in patients with history of venous thrombosis. Further clarification awaits prospective clinical trials that implement risk adapted therapeutic interventions.

Pregnancy in patients with myelofibrosis: Mayo–Florence series of 24 pregnancies in 16 women

“…We were encouraged with the relatively low miscarriage rate of 29%, which is in range with what has been observed in the past with ET (30% fetal loss rate across four of the largest studies); 2 however, the maternal complication rate of 21% was higher in the present report, compared to what has been reported in ET (<10%). 2 Also, as was the case with ET, 2,3,10,11 history of prior fetal loss was predictive of subsequent loss, while use of aspirin therapy during pregnancy or presence of CALR mutations were associated with lower risk of miscarriage. A prior vascular event was detrimental to both risk of fetal loss and maternal complications, requiring special attention regarding management.…”

“…The study included all adult patients with AML registered in the Danish Acute Leukaemia Registry (DNLR) 3 diagnosed 2005-2016 and treated with high-intensity chemotherapy. The baseline patient, disease and treatment characteristics were obtained from the DNLR.…”

“…Among young patients with myeloproliferative neoplasms (MPN), women constitute the majority in essential thrombocythaemia (ET; ˜69% and 64% for ages ≤40 and 41–60 years respectively), whereas the corresponding percentages were lower in polycythaemia vera (PV; 46% and 48%) and primary myelofibrosis (PMF; 41% and 41%) 1,2 . Accordingly, current literature on pregnancies in MPN is heavily skewed towards ET; in a recent review, 3 close to 500 pregnancies in ET were pooled from four independent series with ˜100 or more pregnancies reported in each study, whereas the largest reported experience in PV included 48 women with 121 pregnancies 4 . Current literature regarding pregnancy outcome in patients with MF is scant with <20 reported cases 2,5–7 .…”

Myeloproliferative neoplasms and pregnancy

“…The incidence of pregnancies in patients with MPN is unknown [4]. However, based on a prospective British study, the calculated incidence of MPN pregnancies is 3,2/100 000 maternities per year [5].…”

“…Interferon alpha therapy is the treatment of choice for patients who should receive cytoreductive therapy due to disease-related reasons or in high-risk pregnancies. The recommended initial dose of Interferon alpha is 45 mcg subcutaneously weekly throughout pregnancy, with a duration of post-partum therapy based on clinical and laboratory parameters [4]. Interferon/alpha is recommended in this situations: *Indication for interferon only, rather than interferon plus low molecular weight heparin [6]./Indikacije za interferon alfa, bolje nego kombinacija interferona alfa plus heparin male molekulske težine [6].…”