The goal of this clinical trial is to learn if accelerated transcranial magnetic stimulation (TMS) is a feasible treatment for obsessive compulsive disorder that worsens or starts within 12 months of childbirth. The main questions it aims to answer are:

Is TMS a tolerable and acceptable treatment for postpartum women with OCD?

Does TMS improve OCD symptoms in postpartum women?

Does TMS change connectivity between areas of the brain involved in OCD?

Participants will:

1. Receive 50 sessions of a type of TMS called continuous theta burst stimulation (cTBS) over the course of two weeks.
2. Complete clinical assessments before and after TMS, as well as at 1 and 3 months post-treatment
3. Undergo functional magnetic resonance imaging (fMRI) of the brain before and after TMS

This study will involve a small open-label, single arm feasibility trial of an accelerated cTBS protocol to the right orbitofrontal cortex (rOFC) in postpartum OCD. Following initial screening and consent, all participants (n=15) will undergo a baseline clinical assessment that will record OCD severity and symptom profiles, concurrent anxiety and depressive disorders, contraindications to TMS and medical history. Participants will then undergo a baseline functional magnetic resonance imaging (fMRI) scan at the Brown MRI Research Facility. This will be followed by 10 days of cTBS (5 sessions daily) to the rOFC during which symptoms and adverse effects will be monitored daily using a standardized checklist. At the end of day 5, participants will be asked to repeat some of the self-report clinical symptom measures included in the baseline clinical assessment. At the end of the cTBS protocol, participants will repeat a full clinical assessment, obtain an endpoint fMRI scan, and complete an acceptability questionnaire. Follow-up clinical assessments will be completed at 1-month and 3-months post-treatment either in person or virtually to assess the durability of responses. These data will be used as initial evidence of feasibility for a larger pilot study.

Inclusion Criteria:

1. Age 18-45
2. Diagnosis of OCD defined by DSM-V criteria with problematic symptoms in the 12 months following childbirth
3. YBOCS ≥16
4. Either currently taking OCD medications at a stable dose for 8 weeks or unmedicated
5. Concurrent psychotherapy (exposure and response prevention therapy) will be allowed if it was initiated 8 weeks or more before study entry and continues regularly throughout the trial
6. Ability to read, write and understand English sufficiently well to complete study procedures and provide informed consent.

Exclusion Criteria:

1. Past history of a primary psychotic or bipolar disorder
2. Current acute suicidality or significantly elevated risk of suicide as determined by the investigators
3. Personal history of moderate traumatic brain injury, epilepsy, or other clinically significant neurological illness except tic disorders
4. A history of pre-eclampsia during the most recent pregnancy if the patient is less than 8 weeks postpartum
5. Current, moderate to severe alcohol or illicit substance use disorder in the last 3 months, determined by clinical assessment
6. Women who are currently pregnant. All participants will be asked to use a reasonable birth control method throughout the study period (barrier, oral contraceptives, etc.). We will not administer pregnancy tests.
7. current psychotic symptoms
8. A current seizure disorder
9. active severe major depressive episode as indicated on the Edinburgh Postnatal Depression Scale (greater than or equal to 19).

All de-identified IPD collected throughout the trial may be shared with other researchers for the purposes of collaboration and publication.

From enrollment with no end date

IPD will only be shared upon request and at the discretion of the principal investigator solely for the purposes of collaboration, analysis, or publication. All shared IPD will be de-identified.