.

Objective: The change in size of uterine myomas during pregnancy remains controversial. The aim of this study was to evaluate changes in uterine myoma volume during pregnancy.
Methods: We conducted a review of our medical charts of pregnant women who visited Korea University Ansan Hospital in the period from Jan. 1999 to Sep. 2008. Seventy-seven Pregnant patients who were diagnosed with uterine myomas and had serial ultrasounds to check volume of uterine myoma during different stages of pregnancy were included in the study. The size of uterine myoma was calculated by using the fomula. Size = 1/2 × (long axis) × (short axis) The size change was reclassified into three groups: increased in size (an increased of more than 10% in volume), decreased (a decrease of more than 10% in volume), and inchanged (a change of 10% or less in volume).
Results: The change of myoma size between the different study periods was as follows: between the first and second trimester, 50% of uterine myomas increased; while 15.4% of uterine myomas decreased and 34.6 % had no interval change. Between the second and third trimester, 14.3% increased; while 37.1% decreased and 48.6% had no interval change. Next, we reviewed serial size change of 41 myomas which were measured in all of the different study periods. Between the first and second trimester, the size increased significantly; while between the second and third, decreased and had no interval change between first and third trimester. The changes of myoma size between the different study periods were compared based on prepregnant body mass index. In the group of BMI ≥25, the size significantly increased between first and second trimester, decreased between second and third trimester and had no change between first and third trimester.
Conclusion: In this study, myoma size increased between the first and second trimester, while decreased between the second and third and had no interval change between first and third trimester. Further studies are needed to evaluate the effect of uterine myoma during pregnancy.