He 1991.

Methods	Randomized controlled trial Randomization was conducted according to a "random table" generated by the Shanghai Institute of Planned Parenthood Research. Participants were followed for a period of 10 weeks consisting of a pretreatment cycle, a treatment cycle and the first half of the post‐treatment cycle. They were given a diary card to record basal body temperature, vaginal bleeding, acts of intercourse, days of tablet intake and side effects.
Participants	361 women attending 10 participating centers in China; average age about 30 years
Interventions	One pill of Chinese‐ versus Hungarian‐made tablet of LNG 0.75 mg taken as soon as possible after the first coitus and no later than 8 hours after. A second tablet was taken 24 hours later regardless of whether another coital exposure had occurred during that time. Subsequently, 1 tablet was taken after each further act of intercourse in this cycle with a maximum of 1 tablet per 24‐hour period, irrespective of coital exposures during that period.
Outcomes	Pregnancy (as detected by measuring ß‐hCG in blood), cycle control and other side effects during 1 month of repeated use
Notes	LNG 0.75 mg was to be used during the periovulatory period, defined as days ‐7 to +7 (day 0 = estimated day of ovulation based on the basal body temperature charts of the pretreatment cycle). Except for the periovulatory period, a barrier method (condom) was to be used at other times in the cycle. This study thus did not actually test the postcoital method alone.  This randomized trial compared contraceptive effectiveness and safety of the Chinese‐ and Hungarian‐made tablets. Given the purpose of this review and the fact that no significant difference was found between the 2 types of LNG pills, we included the overall results in the analysis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Incomplete outcome data (attrition bias) All outcomes	Low risk	A total of 153 women were excluded from the study or data analysis: 88 women were excluded during the study prior to treatment for various reasons (e.g., pregnancy, personal, medical, lost to follow‐up); 65 were excluded from data analysis after they received treatment due to protocol violations (erroneous recruitment or treatment).
Selective reporting (reporting bias)	Low risk	Outcomes were specified.
Other bias	High risk	No information on how sample size was determined; no statistical methods
Eligibility criteria	Low risk	Included: healthy, sexually active women with regular menstruation (25 to 35 days) during the past 6 months, aged 21 to 40 years, married, have been pregnant by their present husband within the last 5 years, with no contraindication to hormonal contraception Excluded: women with a history of pelvic inflammatory disease since the last pregnancy, postabortion or postpartum sepsis, difficulty conceiving the last pregnancy, breastfeeding, who had used an IUD or hormonal contraception during the last 3 months, or had abnormal findings on pelvic exam