(275) Influence of Age and Other Risk Factors on Intrauterine Device Expulsion in a Real-World Safety Study - Results from EURAS-LCS12

Publication Number: 949

Background: Complications associated with intrauterine devices (IUD) are relatively rare, and the most common complication is IUD expulsion. Previously described risk factors for expulsion are younger age, obesity, menorrhagia and immediate postabortum/partum insertion.

Objectives: Since IUD use in adolescents is still limited, it is of great interest to investigate whether risk factors for expulsion vary by age groups.

Methods: EURAS-LCS12 is an ongoing prospective, non-interventional cohort study with active surveillance in ten European countries. Women with a newly inserted IUD were enrolled between 2014 - 2021. Information was assessed in case report forms from the women via regular follow-up, and subsequently verified via medical documentation, if available. Multivariable Cox models have been applied to investigate the influence of potential risk factors (e.g., age, BMI, gravidity, parity, heavy menstrual bleeding) on IUD expulsion. Factors were selected based on subject matter knowledge and univariate comparisons.

Results: A total of 77,088 women were included in the analysis. The study sample comprised of 5,528 (7.2%) women who were younger than 20 years. There were 237 partial and complete expulsions with a 3-years cumulative expulsion rate of 6.5 [5.7-7.5]/ 100 IUD users < 20 years of age and 1,840 with a rate of 3.6 [3.5-3.8]/ 100 IUD users among women older than 20 years. Furthermore, expulsion rates were high in obese participant (BMI ≥ 30; 5.4 [4.9-5.9]/100), women who have never been pregnant (5.2 [4.9-5.7]/100) and nulliparous women (5.1 [4.7-5.5]/100). In women aged below 20 years, the cumulative expulsion rate was similar among females with BMI < 30 and BMI of ≥30 with overlapping CI (6.6 [5.7-7.6]/100 vs. 5.5 [3.1-9.8]/100). In women aged above 20 years, expulsion rates were higher in females with an BMI ≥30 compared to BMI < 30 (5.4 [4.9-5.9]/100 vs. 3.3 [3.2-3.5]/100). The rate of expulsions was similar in nulliparous and parous adolescents (6.6 [5.7-7.5]/100 vs. 5.4 [3.1-9.4]/100) but not in nulliparous and parous women (4.7 [4.4-5.2]/100 vs. 3.2 [3.0-3.4]/100) above 20 years of age. A multivariable Cox regression, stratified by age, shows that BMI (BMI ≥30; HR 1.7 [1.5-1.9]) and gravidity (never pregnant; HR 1.6 [1.4-1.7]) are independent risk factors for expulsion in women aged above 20 years, but not in younger women (BMI ≥30; HR 0.8 [0.4-1.5] and never pregnant; HR 1.3 [0.8-2.0]).

Conclusions: More expulsions were observed in females younger than 20 years, regardless of known risk factors. However, there is no increased risk in IUD expulsions among nulliparous or obese adolescents compared to parous and normal weight adolescents