Hormone therapy shows promise in preventing relapse in postpartum meth users

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Meeting criteria for substance use disorder of methamphetamine in the six months prior to conception or during pregnancy * No active methamphetamine use at time of enrollment or within past 4 weeks prior to enrollment by self-report or urine toxicology. * If diagnosis of active opioid use disorder (OUD) and no use at time of enrollment or within past 4 weeks prior to enrollment by self-report or urine toxicology and on stable dose of medication for OUD (methadone, buprenorphine, naltrexone) for two weeks prior to enrollment in order to allow for postpartum dose adjustments. * Intrauterine device or barrier method for contraception during the study period * End of pregnancy within past 12 weeks * Residing within 100 miles of study site * Stable on allowable psychiatric medications including selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and mood stabilizers for four weeks prior to enrollment Exclusion Criteria: * Major medical illness in which progesterone may be contraindicated (significant liver disease, history of thrombophlebitis, stroke, heart disease, suspected or known malignancy, deep vein thrombosis, pulmonary embolus, clotting or bleeding disorders) * Any of the following laboratory abnormalities (within 2 weeks of screening and enrollment) * Active hepatic dysfunction * Anemia defined as hemoglobin less than 8 g/dL indicating anemia * Renal impairment defined as creatinine greater than 2.0 mg/dL * Hypothyroidism defined as TSH greater than 5 mIU/L * Abnormal vital signs at baseline visit * Allergy to micronized progesterone or ingredients in placebo including peanut oil, gelatin or cellulose * Self-reported progestin-containing oral or depot containing contraceptives intolerance. * Do not speak English or Spanish * Taking potent inhibitors of CY P450 3A4 including clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole, ritonavir, verapamil and goldenseal. * Severe depressive symptoms * Active suicidality * Current or past history of psychosis, suicidal attempts or psychiatric hospitalizations * Current or pending incarceration * Active alcohol use disorder within past six months * Use of the following concomitant drugs, supplements and over-the-counter medications in the two week prior to enrollment: stimulants, barbiturates, benzodiazepines, non-benzodiazepine hypnotics, orexin antagonists, first generation anti-histamine, herbal sedatives, methaqualone and analogues, skeletal muscle relaxants, opioids (other than methadone or buprenorphine), anti-psychotic medications, certain anti-depressants or other medication with significant sedative properties as evaluated by the PI and/or study clinician. * Progestin containing medications including oral hormonal contraceptive methods