The relationship between the levonorgestrel-releasing intrauterine system and idiopathic intracranial hypertension

Abstract

Purpose: Unconfirmed reports have linked the levonorgestrel-releasing intrauterine system (LNG-IUS), a long-acting contraceptive, to idiopathic intracranial hypertension (IIH). In this pilot case-control study, we compared LNG-IUS exposure between a cohort of patients with IIH and an analogous cohort of patients without IIH.

Methods: A retrospective series of 473 patients with ICD-9 codes for pseudotumor cerebri (PTC) was screened for female gender, age at onset of 18-55, diagnosis from 2008-2013, and non-idiopathic etiologies. Of 176 eligible participants, 59 completed telephone birth control histories of the 3 month timeframe preceding IIH onset. Records were then queried for CPT codes for LNG-IUS insertion in 220,904 women without ICD-9 codes for PTC who were aged 18-55 and had at least one clinical encounter from 2008-2013. Descriptive statistics and significance tests were performed, and odds ratios were calculated.

Results: Exposure to an LNG-IUS was significantly associated with the development of IIH (OR 7.7, 95% CI 3.2-16.4, p<0.001); the prevalence of IIH was 0.18% in the LNG-IUS population (8/4408, 95% CI 0.07-0.35) versus 0.02% in the non-LNG-IUS population (51/216555, 95% CI 0.01-0.03). Of those IIH patients not on an LNG-IUS, 9 (15%) were on another contraceptive and 42 (71%) were not on any contraceptives. All LNG-IUS users who developed IIH manifested symptoms while the device was still in situ. There were no significant differences between LNG-IUS users and non-users in terms of age, body mass index, recent weight gain, or presenting signs and symptoms.

Conclusions: Our findings suggest that LNG-IUS exposure does not alter the clinical features of IIH; however, it is disproportionately more common among IIH patients than non-IIH patients. Therefore, although a causative role for LNG-IUS has not yet been established, we recommend augmenting the routine evaluation of IIH with a birth control history. IIH patients who are considering options for birth control should be counseled about the possible connection between LNG-IUS and IIH. While the preliminary evidence does not warrant the removal of an LNG-IUS in a typical IIH patient, atypical IIH patients (i.e. non-obese, having no other risk factors) with an LNG-IUS may wish to switch to an alternative contraceptive.