Evaluation of bone marrow function with immature platelet fraction in normal pregnancy.

Background: Bone marrow function in pregnancy is influencing blood cell concentration of platelets. The steady state of consumption, recovery and production of platelets is essential for coagulation and bleeding prevention. Reticulated platelets are an intermediate form of thrombocytes during thrombopoiesis representing platelet production. The immature platelet fraction (IPF) represents these platelets as percentage of all thrombocytes. Until now, there is little knowledge on IPF during pregnancy.

Material And Methods: 69 healthy pregnant women were included in this monocentric study. Serial blood samples of 27 women (study group 1) and single blood samples of 42 women (study group 2) were taken between 20 and 40weeks of gestation. IPF levels and thrombocytes were quantified by a routine clinical hematology analyzer. Both two study groups were analyzed separately.

Results: IPF levels increased between 20 and 40weeks of gestation in both study groups. Median absolute values of IPF increased from 8.1/nl to 13.6/nl in study group 1 and remained constant in study group 2. Values in percent rose from 3.63% to 6.06% in study group 1 and from 4.9% to 6.01% in study group 2. Most values stayed below 20/nl or 7-7.5%. Highest IPF levels were measured near term. In contrast, thrombocyte counts decrease slightly during this period.

Conclusion: Bone marrow function is mirrored by IPF levels, which increase with gestational age in healthy pregnant women. Most IPF values remain below 20/nl or 7%. More studies are needed to improve understanding of thrombocyte turnover in pregnancy.