A meta-analysis of studies involving pregnant women with myeloproliferative neoplasms (MPNs) suggests that use of aspirin or interferon was associated with an increased likelihood of a successful pregnancy. The findings from this study were published in JAMA Network Open.

Although diagnosis of the Philadelphia chromosome-negative MPNs, such as essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF), is most common in patients older than 50, earlier diagnosis of these diseases is being facilitated by more frequent use of sequencing panels and other technological advancements. Hence, sizable proportions of patients with these diseases are younger than 40, and the development of approaches to the management of these diseases in the setting of pregnancy are becoming increasingly relevant.

Twenty-two mostly retrospective studies were included in this meta-analysis; 10 studies focused on maternal outcomes, and 12 focused on fetal outcomes. Fifteen of these studies involved patients with ET; 3 and 4 of the remaining studies included patients with PV or any classical MPN, respectively. None of the studies exclusively evaluated patients with PMF.

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In total, 767 women and 1210 pregnancies were included in the meta-analysis.  The rates of overall live births were 71.1% for patients with ET and 66.7% for patients with PV, both are lower than the rate (80%) found in studies of the general population.

Notably, compared with observation alone, both use of aspirin (unadjusted odds ratio [OR], 8.6; 95% CI, 4.0-18.1) and interferon, with or without aspirin, (unadjusted OR, 9.7; 95% CI, 2.3-41.0) was associated with an increased likelihood of a live birth. However, compared with aspirin alone, the addition of low-molecular weight or unfractionated heparin to aspirin, or administration of low-molecular weight heparin alone, was not associated with further benefit with respect to live birth rate.

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Furthermore, compared with observation alone, treatment with neither aspirin nor interferon was associated with an increased risk of maternal adverse events.

Preeclampsia, venous thrombosis, and arterial thrombosis were reported in 3.4%, 1.5% and 1.3% of patients, respectively. However, no significant associations were demonstrated between the rate of preeclampsia and the use of aspirin or the rates of thrombosis and the use of aspirin or heparin.

The study authors noted that “the prevalence of MPNs in pregnancy appears to be increasing; consequently, there may be an increased need to optimize management of these pregnancies. Efforts focused on establishing collaborations to risk-stratify pregnancies and assess the management of pregnancies systematically with prospective studies or registries are warranted.”


Maze D, Kazi S, Gupta V, et al. Association of treatments for myeloproliferative neoplasms during pregnancy with birth rates and maternal outcomes: A systematic review and meta-analysis [published online October 2, 2019]. JAMA Netw Open. doi: 10.1001/jamanetworkopen.2019.12666