Cases of idiopathic intracranial hypertension have been reported in women who used birth control, such as Implanon. Many women who develop IIH suffer from chronic headaches, migraines, or vision loss, and they may need surgery to relieve pressure inside the skull.
What is Implanon?
Implanon is a type of birth control that is implanted under the skin. The matchstick-sized plastic rod contains etonogestrel, a hormone that helps prevent pregnancy by thickening cervical mucous and inhibiting ovulation. Implanon is sold by Merck & Co. and it has been on the market in the U.S. since 2006.
What is the problem?
During clinical trials of Implanon, 25% of women reported headaches. The Prescribing Information recommends that women with severe headaches should be evaluated by a doctor and discontinue Implanon if necessary.
Headaches are also the most common symptom of Idiopathic Intracranial Hypertension (IIH), reported by more than 90% of people. IIH is a devastating medical condition that can cause permanent blindness.
Does Implanon Cause IIH?
No one knows whether Implanon causes IIH. The term “idiopathic” means that doctors do not know what causes the disease. However, doctors do know that birth control is a potential risk-factor.
Contraceptive implants that contain levonorgestrel were associated with 56 cases of IIH in 1995. Recent studies have also found case reports linking IIH with exogenous estrogen and progestin-only birth control injections.
Complications of IIH
Cerebrospinal fluid is a colorless liquid that bathes the brain and spinal cord. The primary function of this fluid is to cushion the brain and protect it from injury inside the skull. IIH occurs when there is more cerebrospinal fluid than normal, which puts pressure on the brain. IIH used to be called pseudotumor cerebri (PTC) because it produced symptoms that were similar to a growing brain tumor.
Complications from IIH:
- Headache: May be severely painful or dull, located on one side of the head, worst in the morning, or accompanied by visual disturbances or light-sensitivity. Without treatment, headaches from IIH can become constant.
- Papilledema: Swelling (edema) of the optic disc, which is located at the back of the eye (“blind spot”).
- Visual disturbances: Double-vision, blurry vision, temporary blindness (30 seconds), and more.
- Blindness: IIH puts pressure on the optic nerve and can cause permanent nerve damage that leads to blindness.
- Tinnitus: Pressure on internal structures of the ear may produce ringing or “whooshing” sounds.
- And more