Impact of levonorgestrel-releasing intrauterine system on levels of serum hemoglobin and ferritinin women with a normal and elevated body mass:1-year follow-up

Abstract

Objective: To explore the relationship between overweight and iron status and identify the prevalence and nature of iron deficiency (ID) in a cohort of young healthy overweight and normal weight women using the levonorgestrel-releasing intrauterine system (LNG IUS) as a contraceptive method.|
Design: Prospective non-randomized open-label trial.|
Sample: 33 women who wanted to use the LNG IUS for contraception.|
Methods: The participants were divided into 2 groups according to their body mass index (BMI) at the beginning of the research: 19 women formed the LNG-IUS I group (BMI ≤25); 14 women were included in the LNG-IUS II group (BMI≥25). The women were also analyzed according to levels of serum hemoglobin: >120 g/L (non-anemic) and <120 g/L (anemic) and serum ferritin: <15ng/mL (iron deficiency) and >15 ng/mL.|
Results: At the beginning of the research, 12 women (22.2%) were diagnosed with anemia and 15 women (27.8%) with severe iron deficiency (<15 ng/mL). After six months of using the contraception, statistically significant increases in S-Hb were found in both S-Hb <120 subgroups (+20.2; p=0.01 and +21.1; p< 0.05 g/L), respectively. Instead, S-Fe increased in the LNG-IUS I group (+17.58; p=0.01 ng/L) but decreased in the LNG-IUS II group (-8.45; p=0.50 ng/L). After 12 months’ use of the contraceptive method, S-Fe increased by +11.00; p=0.11 ng/mL in the LNG-IUS I group, but decreased by -1.07; p=0.3 ng/mL in the LNG-IUS II group.| Conclusions: There are various possible reasons for iron deficiency anemia among women with different BMIs, and it cannot be explained only by menstrual bleeding patterns. Our study shows that, among women who chose the LNG IUS for contraception, serum hemoglobin and ferritin levels increased faster in the group with a normal body mass than in the group with elevated body mass.