Rct Assessing Pregnancy - Piroxicam for Ec With Levonorgestrel

Inclusion Criteria: * Between 16-35 years old and desire LNG for EC * Unprotected intercourse within 72 hours * Biologically capable of pregnancy * Regular menstrual cycle 21-35 days long with known LMP +/- 3 days * Working cell phone number that receives text messages (for Aim 3 participants phone with capability to download and use the Oova application and submit data) * Fluent in English and/or Spanish * Willing to comply with the study requirements including 1-month urine pregnancy test * No known contraindications to oral LNG or piroxicam - For secondary outcome assessing pregnancy risk for participants receiving study drug on day of ovulation or later - are currently using a menstrual cycle tracking application and can demonstrate according to the application that they are on the day of ovulation or post ovulation. Exclusion Criteria: * Current pregnancy (+urine pregnancy test in clinic) * Breastfeeding, post abortion or postpartum without resuming menstruation * Use of hormonal contraception (including oral EC) within seven days of enrollment * Use of NSAIDs (ibuprofen, naproxen, celecoxib, diclofenac, aspirin) in the prior week * Highly effective contraception including permanent contraception (including partner with vasectomy), IUD, or contraceptive implant * Allergy to LNG or piroxicam * Desires UPA for EC History of stroke, myocardia infarction, ischemic heart disease, uncontrolled hypertension, congestive heart failure, peptic ulcer disease, renal…