Certain types of birth control pills and implants have been associated with dozens of cases of Benign Intracranial Hypertension (BIH), a rare but serous brain injury that can cause painful headaches and blindness.
Benign Intracranial Hypertension (BIH) is a rare neurological disorder that can cause permanent blindness. It occurs when abnormally high levels of cerebrospinal fluid increase pressure inside the skull. Other names for BIH include pseudotumor cerebri (PTC) and idiopathic intracranial hypertension (IIH).
BIH and Birth Control
Officials with the National Institute of Health (NIH) warn that birth control pills are a risk-factor for BIH. Case reports have linked BIH with exogenous estrogen, progestin-only implants, and birth control injections. In 1995, the New England Journal of Medicine linked levonorgestrel, a popular hormone in birth control implants, with 56 cases of intracranial hypertension and optic disc edema. Other studies have linked BIH with exogenous estrogen and progestin-only implants.
Headaches and Migraines
Over 90% of people with BIH report headaches, including migraines. Symptoms include severe pain that is throbbing or pulsating, often located at the back of the head, and worsens in the early morning or at night. Without treatment, the headaches can become progressively more common and may be accompanied by nausea, light-sensitivity, and visual disturbances.
Over two-thirds of people with BIH report vision problems, but only about 5% of people develop blindness. Symptoms may include:
- Double vision (diplopia)
- Episodes of blurry vision lasting 30 seconds
- Loss of visual field
- Temporary blindness
Papilledema is a complication of BIH that occurs when pressure in the skull causes swelling (edema) of the optic disc. The optic disc is the donut-shaped head of the optic nerve at the back of the eye at the same physical location as the “blind spot.” Over time, damage to the optic nerve causes the blind spot to grow progressively larger and reduces the field of vision.
Diagnosis & Treatment
BIH is diagnosed with a lumbar puncture (spinal tap), a painful medical test in which a needle is used to remove cerebrospinal fluid from the spine. This may also help alleviate headache symptoms. Eye exams can also diagnose papilledema. Treatment for BIH may involve a combination of medications and surgery to drain fluid from the skull using a shunt.