***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: Objective To compare 100 mg mifepristone with the st and ard Yuzpe regimen for emergency contraception OBJECTIVE To compare the efficacy , side effects and the effect on next menstruation of levonorgestrel(LNG ) to low dose mifepristone in emergency contraception . METHODS The study is a r and omized double-blind multicenter comparative trial . The clients who have unprotected intercourse within 72 hours were allocated to one of the two study groups . In LNG group , 0.75 mg LNG was taken twice with 12 hours apart . In mifepristone ( Mife- ) group , single dose of 10 mg mifepristone was taken and a placebo 12 hours after . Follow-up visit was paid on the seventh day of the expected next menstruation to evaluate the contraceptive efficacy and to record side effects and menstruation . Contraceptive efficacy was calculated by Dixon 's method . RESULTS The total valid subjects in LNG and Mife- group were 643 and 633 , respectively . There were 20 and 9 pregnancies occurred respectively in each group . The failure rate was 3.1 % and 1.4 % . Contraceptive efficacy rate of preventing pregnancy was 59.2 % and 79.7 % , the difference was statistically significant ( P < 0.05 ) . The incidence of various side effects was less than 10.0 % which were mild . There was no statistically difference between the two groups . The percentage of subjects who had their next menstruation before or after their expected menstruation 3 days in LNG group and Mife- group was 77.7 % and 78.5 % respectively . The menstrual period less than 7 days was 95.0 % and 93.3 % . CONCLUSION Use of levonorgestrel or low dose mifepristone for emergency contraception is effective and safe BACKGROUND A single 10 mg dose of mifepristone , and two 0.75 mg doses of levonorgestrel 12 h apart , are effective for emergency contraception . Because no studies had compared the efficacies of both compounds , or investigated a single dose of 1.5 mg levonorgestrel , we undertook this three-arm trial . METHODS We did a r and omised , double-blind trial in 15 family-planning clinics in 10 countries . We r and omly assigned 4136 healthy women with regular menstrual cycles , who requested emergency contraception within 120 h of one unprotected coitus , to one of three regimens : 10 mg single-dose mifepristone ; 1.5 mg single-dose levonorgestrel ; or two doses of 0.75 mg levonorgestrel given 12 h apart . The primary outcome was unintended pregnancy ; other outcomes were side-effects and timing of next menstruation . Analysis was by intention to treat , but we did exclude some patients from the final analyses . FINDINGS Of 4071 women with known outcome , pregnancy rates were 1.5 % ( 21/1359 ) in those given mifepristone , 1.5 % ( 20/1356 ) in those assigned single-dose levonorgestrel , and 1.8 % ( 24/1356 ) in women assigned two-dose levonorgestrel . These proportions did not differ significantly ( p=0.83 ) . The relative risk of pregnancy for single-dose levonorgestrel compared with two-dose levonorgestrel was 0.83 ( 95 % CI 0.46 - 1.50 ) , and that for levonorgestrel ( the two regimens combined ) compared with mifepristone , 1.05 ( 0.63 - 1.76 ) . Side-effects were mild and did not differ greatly between groups , and most women menstruated within 2 days of the expected date . Women who took levonorgestrel had earlier menses than did those who took mifepristone . INTERPRETATION The three regimens studied are very efficacious for emergency contraception and prevent a high proportion of pregnancies if taken within 5 days of unprotected coitus . Mifepristone and levonorgestrel do not differ in efficacy . A 1.5 mg single levonorgestrel dose can substitute two 0.75 mg doses 12 h apart Abstract Background We aim ed to compare acceptability of Levonorgestrel with the Yuzpe regimen among Iranian women based on their side-effects and result ing changes in the amount and pattern of menses . Methods Five hundred twenty nine participants aged 15 - 49 having regular menses and one act of unprotected intercourse within 72 h were included in the double-blind , controlled trial in 2006 - 2007 and r and omly assigned into LNG ( n=263 ) and HD ( n=266 ) groups , receiving Levonorgestrel 0.75 mg given 12 h apart and ethinyl estradiol 100 μg plus 0.5 mg Levonorgestrel 0.5 mg repeated after 12 h , respectively . Results The participants receiving Levonorgestrel experienced significantly lower side-effects in the case of nausea , vomiting , and dizziness ( P<0.05 ) . The changes occurred in the amount and pattern of menses were the same for both groups ( P>0.05 ) . No significant difference was observed between the efficiencies of the treatments . Conclusion Significantly lower side-effects of Levonorgestrel can be considered as greater acceptability and translated to higher efficiency Purpose To estimate the efficacy and safety of 5 mg and 10 mg mifepristone for emergency contraception up to 144 hours after unprotected coitus . Methods This double-blind r and omized clinical trial was carried out at Eusebio Hern and ez Hospital ( Havana , Cuba ) . A total of 2,418 women who requested emergency contraception after unprotected coitus received either 5 mg or 10 mg mifepristone . The variables for assessing efficacy were the pregnancies that occurred and the fraction of pregnancies that were prevented . Other variables assessed were the side effects of mifepristone , vaginal bleeding , and changes in the date of the following menstruation . Results There were 15/1,206 ( 1.2 % ) and 9/1,212 ( 0.7 % ) pregnancies in the 5 mg and 10 mg group , respectively ( P=0.107 ) . There were 88 % and 93 % prevented pregnancies in the 5 mg and un ≥7 days was experienced by 4.9 % and 11.0 % of subjects in the 5 mg and 10 mg group , respectively ( P=0.001 ) . There was a significant high failure rate for women weighing > 75 kg in the 5 mg group . Conclusion It would be advisable to use the 10 mg dose of mifepristone for emergency contraception as there was a trend suggesting that the failure rate of the larger dose was lower OBJECTIVE : To evaluate the efficacy and safety of ulipristal acetate as emergency contraception in women presenting 48–120 hours after receiving ulipristal acetate for unprotected intercourse . METHODS : Women aged 18 years or older with regular cycles who presented for emergency contraception 48 to 120 hours after unprotected intercourse were enrolled in 45 Planned Parenthood clinics and treated with a single dose of 30 mg ulipristal acetate .  Pregnancy status was determined by high-sensitivity urinary human chorionic gonadotropin testing and return of menses . RESULTS : A total of 1,241 women were evaluated for efficacy . Twenty-six were pregnant at follow-up , for a pregnancy rate of 2.1 % ( 95 % confidence interval 1.4–3.1 % ) . These results satisfy the protocol -defined statistical criteria for success because the pregnancy rate was lower than both the estimated expected pregnancy rate and a predefined clinical ir relevance threshold . In addition , efficacy did not decrease over time : pregnancy rates were 2.3 % ( 1.4–3.8 % ) , 2.1 % ( 1.0–4.1 % ) , and 1.3 % ( 0.1–4.8 % ) for intervals of 48 to 72 hours , more than 72 to 96 hours , and more than 96 to 120 hours , respectively . Adverse events were mainly mild or moderate , the most frequent being headache , nausea , and abdominal pain . Cycle length increased a mean of 2.8 days , whereas the duration of menstrual bleeding did not change . CONCLUSION : Ulipristal acetate is effective and well-tolerated for emergency contraception 48–120 hours after unprotected intercourse . LEVEL OF EVIDENCE : BACKGROUND An enteric-coated levonorgestrel emergency contraceptive pill ( E-LNG-ECP ) is an improved formulation , in terms of side effects , which both dissolves and is absorbed in the intestine . Our aim was to evaluate the efficacy and safety of E-LNG-ECP as an over-the-counter ( OTC ) drug for emergency contraception ( EC ) in Chinese women . METHODS A Phase IV clinical trial was conducted in five family planning clinics in China . Women seeking EC within 72 h after unprotected sexual intercourse or contraceptive failure who met the inclusion criteria were recruited . The efficacy of contraception ( primary end-point was pregnancy rate ) , side effects ( i.e. safety ) and the value of E-LNG-ECP  for EC were investigated . RESULTS Of 2445 women ( aged 15–48 years ) who took E-LNG-ECP with follow-up to determine pregnancy , only five pregnancies ( 0.2 % ) occurred . The efficacy of contraception was 95.3 % . In total , 6.5 % of women reported at least one adverse event after taking E-LNG-ECP , and no serious adverse events were reported . Only four subjects ( 0.16 % ) reported vomiting . The incidence of menstrual cycle disturbance was 20.1 % after taking E-LNG-ECP . Subjects who had previously taken ECPs  ( 54.4 % of these women ) rated the acceptability of E-LNG-ECP at 9.36 ( on a 10-point scale ) higher ( P<0.05 ) than the rating of other LNG-EC pills taken previously . CONCLUSIONS The study found that E-LNG-ECP was effective , safe and well tolerated as an OTC drug . However , an r and omized controlled trial should be performed to compare st and ard LNG tablets with E-LNG-ECP Twenty-seven women requesting postcoital contraception were r and omly allocated to take an ethinylestradiol/dl-norgestrel combination or danazol . Urine specimens were assayed for luteinising hormone ( LH ) and pregnanediol-3-glucuronide ( P3 G ) levels from the day of the postcoital treatment to the next period . In addition , the urine sample s of these recruits and 12 additional women were assayed for the Beta-subunit of human chorionic gonadotropin ( B-hCG ) . A consistent pattern of alteration in urinary steroids was lacking , indicating a heterogeneous effect on ovarian function . There was no evidence of early pregnancy in successfully treated cases . We suggest that the main mechanism of action of these drugs is at the endometrial level OBJECTIVE --To compare the effectiveness and acceptability of three regimens of postcoital contraception . DESIGN --R and omised group comparison of ethinyloestradiol 100 micrograms plus levonorgestrel 500 micrograms repeated after 12 hours ( Yuzpe method ) ; danazol 600 mg repeated after 12 hours ; and mifepristone 600 mg single dose . SETTING --Community family planning clinic . SUBJECTS--616 consecutive women with regular cycles aged 16 to 45 years . MAIN OUTCOME MEASURES --Number of pregnancies , incidence of side effects , and timing of next period . RESULTS --The raw pregnancy rates ( with 95 % confidence intervals ) for the Yuzpe , danazol , and mifepristone groups were 2.62 % ( 0.86 % to 6.00 % ) , 4.66 % ( 2.15 % to 8.67 % ) , and 0 % ( 0 % to 1.87 % ) respectively . Overall , these rates differed significantly ( chi 2 = 8.988 , df = 2 ; p = 0.011 ) . The differences between the mifepristone and Yuzpe groups and between the mifepristone and danazol groups were also significant . Side effects were more common and more severe in the Yuzpe group ( 133 women ( 70 % ) ) than in either the danazol group ( 58 ( 30 % ) ) or the mifepristone group ( 72 ( 37 % ) ) . The Yuzpe regimen tended to induce bleeding early but mifepristone prolonged the cycle . Three women bled more than seven days late in the Yuzpe group compared with 49 in the mifepristone group . CONCLUSIONS --Mifepristone was effective in reducing expected pregnancy rates and the Yuzpe method also had a clinical effect . Danazol had little or no effect . A further multicentre trial is needed Objective We conducted a r and omized trial to determine whether pretreatment with meclizine reduces the incidence of nausea and vomiting associated with the Yuzpe regimen of emergency contraception . Methods We r and 
    Output:
    
Adverse effectsNausea and vomiting were the main adverse effects associated with emergency contraception .
Menstrual delay was more common with mifepristone than with any other intervention and appeared to be dose-related .
Levonorgestrel and mid-dose mifepristone ( 25 mg to 50 mg ) were more effective than Yuzpe regimen .
Mifepristone low dose ( less than 25 mg ) was less effective than mid-dose mifepristone .
UPA was more effective than levonorgestrel .
Levonorgestrel users had fewer side effects than Yuzpe users , and appeared to be more likely to have a menstrual return before the expected date .
UPA users were probably more likely to have a menstrual return after the expected date .
Menstrual delay was probably the main adverse effect of mifepristone and seemed to be dose-related .
Cu-IUD may be associated with higher risks of abdominal pain than ECPs