Hematopoietic Stem Cell Mobilization in Pregnancy

The primary objective of this study was to investigate hematopoietic stem cells (HSC) mobilization into peripheral blood throughout pregnancy, and postpartum, compared to non-pregnant controls. This observational, prospective, longitudinal study was approved by the UCONN Health institutional review board. Participants were recruited between October 2020 and February 2022. Participants were female, 18-40 years old, and receiving care at the study site. Patients with major medical problems were excluded. Pregnant participants were permitted a collection of five blood samples over the course of pregnancy and postpartum. Non-pregnant controls consented to a single blood collection. Flow cytometry was used to measure mobilized HSC concentration in peripheral blood. Baseline demographics, pregnancy, and neonatal information were abstracted from study participants' medical charts. ANOVA was used for data analysis; P < 0.05 was significant. 54 participants were enrolled (47 pregnant, 7 non-pregnant). At baseline, the non-pregnant controls had a higher BMI compared with the pregnant cohort (p= 0.01). In the pregnant cohort, HSC mobilization was increased throughout pregnancy (p< 0.001) and significantly decreased postpartum (p< 0.001) (Figure 1). A significant increase in the number of mobilized HSCs was observed at delivery in the pregnant cohort compared to non-pregnant controls (p< 0.001). This significant relationship remained present after adjusting for weight and BMI (p< 0.001). A positive correlation was observed between mobilized HSC number and gestational age (p< 0.001) (Figure 2). Our study showed an increase in HSC mobilization throughout pregnancy and is positively correlated with gestational age. We speculate this response may be due to a signaling pathway that could be propagated by advancing gestational age. We plan to explore the mechanisms that induce HSC mobilization in pregnancy, and any association between HSC mobilization and adverse pregnancy outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)