Neuropathic Pain in Pregnancy

Neuropathic pain is a common pain disorder that is caused by problems in the nervous system. It affects more women than men and commonly occurs in pregnancy. Physicians have little information to guide their treatment of neuropathic pain in pregnancy. The overall goal of this study is to define the course, management, and pregnancy outcomes of neuropathic pain in pregnancy and the acute postpartum period. It is difficult to manage neuropathic pain in pregnancy as treatment options must minimize their risk to the unborn child as they have a direct effect on infant outcomes through their exposure in utero. Thus, other treatments are needed. Repetitive transcranial magnetic stimulation (rTMS) may be an acceptable alternative to medications. Transcranial magnetic stimulation uses a magnetic force to change the way nerves work in the brain. This non-invasive and localized mechanism of action makes it attractive for use in special populations, such as pregnancy. Study visits will occur approximately every 4-6 weeks during pregnancy until approximately 3 months postpartum for a maximum of 12 visits.

Part A

Inclusion criteria

• age 18-45 years old,
• ability to give informed consent,
• viable pregnancy, and
• enrollment prior or equal to 24 weeks gestation

Exclusion criteria

• Active or history of substance use disorder within the past year
• Non-English speaking

Part B

Inclusion criteria

• Subjects enrolled in Part A and willing to consent to Part B of this protocol
• Pregnant with current chronic neuropathic pain
• Subjects failed treatment with amitriptyline or nortriptyline as defined by one of the following:

• no clinical improvement following a 4-week trial of amitriptyline or nortriptyline (i.e., CGI-I score ≥4)
• an inability to tolerate the medication (i.e., side effects)
• Subjects must pass the TMS Safety Checklist Adult Safety Screen (TASS).
• Subjects should be off medication, which can lower seizure thresholds (e.g., amitriptyline and nortriptyline) for at least two weeks prior to study entry.
• Subjects with neuropathic pain including those with diagnosis of spinal cord injury, fibromyalgia, compression neuropathies (including diabetic peripheral neuropathy), post stroke pain, and multiple sclerosis
• Subjects with a baseline VAS score greater than 30

Exclusion criteria

• Current or past history of a seizure disorder (e.g., epilepsy)
• Current history of preeclampsia
• Current or history of brain lesions (e.g., aneurysm)
• History of major head trauma (e.g., stroke; previous cranial neurosurgery)
• Ferromagnetic metal in the head, neck, or chest (e.g., plates or pins, bullets, shrapnel)
• Microprocessor implants in the head (e.g., cochlear implants) or life-sustaining microprocessor implants anywhere in the body (e.g., prosthetic cardiac valves)
• Cardiac pacemaker
• Active or inactive implants (e.g., deep brain stimulators, vagus nerve stimulators)
• Active treatment with medications that lower seizure threshold (e.g., bupropion, amitriptyline, nortriptyline, or other TCA)
• Increased intracranial pressure (which lowers seizure threshold)
• Implanted medication pumps
• Intracardiac lines
• Significant heart disease defined as heart disease that causes moderate to severe symptoms and/or is characterized by moderate to severe pathology, including a recent history of myocardial infarction and heart failure with an ejection fraction of less than 30% or with a New York Heart Association Functional Classification of Class III or IV.
• Bipolar disorder (to reduce the risk of mania)
• History of suicide attempt(s)
• Family history of epilepsy
• Heavy alcohol consumption within the past 48 hours
• Permanent makeup or tattoos with metallic dyes