Pregnancy in patients with Ph-negative myeloproliferative neoplasms: therapy and prevention of complications

Background. Pregnancy in patients with Ph-negative myeloproliferative neoplasms (MPN) is often accompanied by complications – both for the mother and the fetus.

Aim. To investigate complications and pregnancy outcomes in patients with Ph-negative MPN depending on the nosological form and the therapy administered during the gestational period.

Materials and methods. This retrospective study included 122 women with Ph-negative MPNs (essential thrombocythemia, polycythemia vera, and primary myelofibrosis) followed at the National Medical Research Center for Hematology from 2014 to 2024, with 165 pregnancies recorded. The structure of obstetric complications and pregnancy outcomes depending on the MPN nosological variant and treatment regimen was assessed using data extracted from medical records (outpatient charts, medical histories of childbirth).

Results. The effect of various treatment regimens on the incidence of pregnancy complications was analyzed in 122 patients with Ph-negative myeloproliferative neoplasms of reproductive age, who had a total of 165 pregnancies. In this group, the proportion of pregnancies resulting in live birth was 67.8 %. Among 120 pregnancies prolonged after the first trimester, complications were observed in 72.5 % (87 / 120) of cases. The most common of them were threatened miscarriage (20.8 %), bleeding during pregnancy or childbirth (13.3 %), preeclampsia (9.2 %); the incidence of thrombotic complications was 4.2 %.

Multivariate analysis revealed an independent protective effect of low molecular weight heparin: its inclusion in the treatment regimen reduced the probability of pregnancy complications by 68 % (odds ratio (OR) 0.32; 95 % confidence interval 0.12–0.86; p = 0.03). Acetylsalicylic acid and interferon α did not demonstrate a statistically significant independent effect (p = 0.51 and p = 0.69, respectively). In contrast to triple therapy, the interferon α + acetylsalicylic acid combination was associated with a significantly increased risk of complications (OR 3.6; p = 0.05). Other treatment regimens did not show a significant effect on the incidence of pregnancy complications.

In polycythemia vera, the three-component treatment regimen showed a tendency to reduce the incidence of pregnancy complications (OR 0.24; p = 0.07), and the results of multivariate analysis confirmed that low molecular weight heparin is the main independent protector (OR 0.31; p = 0.02)

Conclusion. The obtained data substantiate the need for a differentiated approach to choosing a therapeutic strategy in pregnant women with various forms of myeloproliferative neoplasms.