This is a randomised controlled trial aimed at comparing the efficacy of levonorgestrel (LNG) co-administered with piroxicam or placebo for oral emergency contraception (EC). Piroxicam is a non-steroidal anti-inflammatory drug (NSAID) commonly used as a pain-killer in inflammatory conditions. Efficacy will be measured as the percentage of pregnancies prevented.

Objective: To compare the percentage of pregnancies prevented by LNG co-administered with piroxicam or placebo for oral emergency contraception (EC) by a randomised controlled trial.

Hypothesis to be tested: LNG plus piroxicam has higher percentage of pregnancies prevented compared with LNG plus placebo for oral emergency contraception.

Design and subjects: This will be a prospective, randomised placebo-controlled clinical trial. Women attending the Family Planning Association of Hong Kong for oral EC within 72 hours of unprotected sexual intercourse will be recruited.

Study instruments: Prospective follow-up of subjects in the clinic for the primary and secondary outcomes.

Interventions: Eligible subjects will be randomised to receive one of the two treatment regimens, i.e. Group A: a single dose of LNG 1.5 mg and piroxicam 40 mg, or Group B: a single dose of LNG 1.5mg and placebo under direct supervision.

Main outcome measures: Percentage of pregnancies prevented (PPP) is the primary outcome measure. Secondary outcome measures include failure rate, rate of occurrence of side effects and pattern of the menstruation following EC.

Data analysis:The percentage of pregnancies prevented, failure rate and rate of occurrence of side effects will be compared between groups using Fisher-Exact test. Continuous variables regarding menstrual pattern between the two groups will be compared by Mann-Whitney U test.

Expected results: LNG plus piroxicam has a higher PPP compared to LNG plus placebo.

Inclusion Criteria:

• healthy women aged 18 years or above;
• requesting emergency contraception within 72 h of a single act of unprotected intercourse in the current menstrual cycle;
• having menstrual cycles between 24 and 42 days
• willing to abstain from further acts of unprotected intercourse and;
• available for follow-up over the next 6 weeks.

Exclusion Criteria:

• post-abortion or postpartum and period have not yet returned,
• being on prescription drugs currently
• having unprotected intercourse in this cycle more than 72 hours or more than once before attending the clinic,
• being found pregnant at the time of presentation,
• breastfeeding,
• having been sterilized (or partner having been sterilized) or having intrauterine contraceptive device in-situ,
• uncertain about the date of the last menstrual period,
• having used hormonal contraceptive (including EC pill) or NSAID in the current or past one cycle,
• having history of asthma, urticarial or other allergic reactions to piroxicam, aspirin or other NSAIDs,
• having history of ischaemic heart disease in the past one year
• having history of pelvic ulcer disease and/or gastrointestinal bleeding

Only females are eligible

To be assessed and endorsed by the investigation team based on the exact study protocol suggested by the other researchers.

starting 6 months after publication of results

To be assessed and endorsed by the investigation team based on the exact study protocol suggested by the other researchers.

3 days