Emergency contraception in Cuba with 10 mg of mifepristone

Background?Mifepristone in a dose of 10 mg is an effective emergency contraceptive when administered up to 120 hours after unprotected coitus.

Methods?Between May 2003 and February 2005, we conducted in Cuba a single-arm trial to evaluate the effectiveness of 10 mg mifepristone for emergency contraception up to 6 days after unprotected coitus. A total of 635 women who requested emergency contraception after a single act of unprotected intercourse were included in the study.

Results?After treatment there were 7/635 (1.1%) pregnancies (95% CI 0.4–2.3%). Pregnancy that might have occurred was prevented in 88.0% of the cases (95% CI 77.1–95.1%). The most common side effects reported by participants were fatigue (10.7%), dizziness (6.1%) and nausea (4.9%); vomiting was only reported by 0.6%. In 38/635 (6.0%) women menstruation was delayed more than 7 days.

Conclusions?Mifepristone 10 mg administered is an effective emergency contraceptive with an acceptable profile of side effects up to five days, but greater studies are necessary to verify its efficacy up to 6 days after unprotected intercourse.     

A randomised study comparing a low dose of mifepristone and the Yuzpe regimen for emergency contraception

Objective To compare 100 mg mifepristone with the standard Yuzpe regimen for emergency contraception.
Design Randomised controlled trial.
Setting Family Planning Clinic, Aberdeen.
Sample One thousand women seeking emergency contraception within 72 hours after an episode of unprotected sexual intercourse.
Methods Women were randomised to receive either 100 mg (half tablet) of mifepristone as a single dose or the Yuzpe regimen (two tablets each with 50 μg ethinyloestradiol and 0.25 mg levonorgestrel, to be repeated 12 hours later).
Outcome measures Crude pregnancy rates, proportion of pregnancies prevented, side effects and patient acceptability.
Results The crude pregnancy rates (95% CI) for the Yuzpe regimen and mifepristone were 3.6% (2.3–5.7) and 0.6% (0.2–1.8), respectively, with a significant difference between the two groups (RR 6.04; 95% CI 1.75–20.75). Mifepristone prevented 92% of pregnancies and the Yuzpe regimen preventing 56%. An increasing coitus to treatment interval was associated with contraceptive failure in the Yuzpe group (   P = 0.03  ) with no association seen with mifepristone. Following administration of mifepristone 24.5% and 13.1% given the Yuzpe regimen had a delayed period (RR 2.14; 95% CI 1.46–3.15). Overall, mifepristone was better tolerated than the Yuzpe regimen with significantly fewer side effects. More women were satisfied (   P < 0.0001  ) with mifepristone as an emergency contraceptive and would recommend it to a friend (   P = 0.02  ).
Conclusion Mifepristone administered in a 100 mg dose is a highly effective post-coital contraceptive with high patient acceptability and fewer side effects compared with the standard Yuzpe regimen. Delay in the onset of menstruation did not decrease patient acceptability.     

Advance supply of emergency contraception. effect on use and usual contraception--a randomized trial

OBJECTIVE: To evaluate whether advance provision of emergency contraception increases its use and/or adversely affects usual contraceptive practices. METHODS: We performed a randomized controlled trial comparing advance provision of emergency contraception with usual care in 370 postpartum women from an inner-city public hospital. Participants were followed for 1 year; 85% were available for at least one follow-up session. All participants received routine contraceptive education. The intervention group received a supply of emergency contraception (eight oral contraceptive pills containing 0.15 mg of levonorgestrel and 30 microg of ethinyl estradiol) and a 5-minute educational session. We compared use of emergency contraception and changes in contraceptive behaviors between groups. RESULTS: Women provided with pills were four times as likely to have used emergency contraception as women in the control group over the course of the year (17% versus 4%; relative risk [RR] 4.0; 95% confidence interval [CI] 1.8, 9.0). Women were no more likely to have changed to a less effective method of birth control (30% versus 33%; RR 0.92; 95% CI 0.63, 1.3), or to be using contraception less consistently (18% versus 25%; RR 0.74; 95% CI 0.45, 1.2). About half of each group reported at least one episode of unprotected intercourse during follow-up, but women who received emergency contraception were six times as likely to have used it (25% versus 4%; RR 5.8; 95% CI 2.1, 16.4). CONCLUSION: Advance provision of emergency contraception significantly increased use without adversely affecting use of routine contraception. It is safe and appropriate to provide emergency contraception to all postpartum women before discharge from the hospital.     

两种紧急避孕方法比较性研究

目的 :比较不同低剂量米非司酮配伍米索前列醇与单服米非司酮用于紧急避孕的效果及其副反应。方法 :运用随机双盲多中心临床比较 ,研究 899例健康妇女在无保护性性交后 1 2 0 h内 ,随机分为 3组。组 (3 0 0例 ) :口服 2 5 mg米非司酮 ,2 4 h后口服 0 .2 mg米索前列醇 ;组 (2 99例 ) :口服 1 0 mg米非司酮 ,2 4 h后口服 0 .2 mg米索前列醇 ;组 (3 0 0例 ) :单服米非司酮 1 0 mg。按 Dixon法推算避孕有效率。结果 :899例妇女中总妊娠数 1 1例 :组 2例 ,组 2例 ,组 7例 ;方法失败 :组 1例 ,组 0例 ,组 5例 ;避孕有效率分别为 95 .5 %、1 0 0 %、76 .9%。组 加组 与组 相比有极显著差异 (P<0 .0 1 )。副反应较轻均可耐受 ,无严重副反应。米非司酮配伍米索前列醇与单服米非司酮组间副反应也无显著差异。结论 :应用低剂量米非司酮和米索前列醇作为紧急避孕是有效安全的紧急避孕方案 ,且对月经周期无明显干扰。     

The potential of mifepristone (RU-486) as an emergency contraceptive drug

The potential of mifepristone to be an emergency contraceptive is reviewed. Mifepristone prevents 92-100% of pregnancies with an acceptable side-effect profile on oral intake of a 10-600-mg dose within 72 h of unprotected intercourse. A single dose of 10 mg mifepristone resulted in a pregnancy rate of 1.5%, similar to a 1.5-mg single dose or two doses of 0.75 mg levonorgestrel 12 h apart, administered within 120 h (current standard) of unprotected sexual intercourse. Mifepristone and levonorgestrel do not differ in efficacy as emergency contraceptives. The mode of action of emergency contraception (EC) with mifepristone or levonorgestrel is primarily associated with inhibition of ovulation rather than prevention of implantation. Different doses of mifepristone appear to have similar effects. However, delay in the onset of subsequent menstruation caused by mifepristone is dose dependent and is reduced with a lower dose without affecting its efficacy. Patient acceptability of mifepristone as EC is high. However, the optimum standard dose of mifepristone is yet to be established for its application as an effective and acceptable emergency contraceptive drug for ordinary clinical use or practice.     

Emergency contraception: randomized comparison of advance provision and information only

OBJECTIVE: To determine whether multiple courses of emergency contraceptive therapy supplied in advance of need would tempt women using barrier methods to take risks with their more effective ongoing contraceptive methods. METHODS: We randomly assigned 411 condom users attending an urban family planning clinic in Pune, India, to receive either information about emergency contraception along with three courses of therapy to keep in case of need, or to receive only information, including that about the locations where they could obtain emergency contraception if needed. For up to 1 year, women returned quarterly for follow-up, answering questions about unprotected intercourse, emergency contraceptive use, pregnancies, sexually transmitted infections, and acceptability. RESULTS: Women given advance supplies reported unprotected intercourse at rates nearly identical to those among women given only information (0.012 versus 0.016 acts per month). Among those who did have unprotected intercourse, however, supply recipients were nearly twice as likely (79% versus 44%) to have taken emergency contraception, although numbers were too small to permit statistically significant inferences. No women used emergency contraception more than once during the study, even though everyone in the advance-supplies group had extra doses available. All women found knowing about emergency contraception useful, and all those receiving only information wished they had received supplies as well. CONCLUSION: Multiple emergency contraception doses supplied in advance did not tempt condom users to risk unprotected intercourse. After unprotected intercourse, however, those with pills on hand used them more often. Women found advance provision useful.     

Notfallkontrazeption

During the last 40 years, numerous methods for postcoital contraception have been developed, including the Yuzpe method (ethinyl estradiol (EE) and levonorgestrel (LNG) up to 72 hours after unprotected sexual intercourse) and levonorgestrel method, whereby there are two application possibilities: LNG alone is administered in two doses (0.75 mg twice 12 hours apart) or administered as a single 1.5 mg dose (good effectiveness with the user friendliness of a single dose, currently still standard in most countries). Nevertheless, the effectiveness of LNG decreases with increasing time since the unprotected sexual intercourse. In Asia, the progesterone receptor antagonist mifepristone is administered in doses of 10 or 25 mg; however, this method is seldom used in Europe. The latest development is the licensing (in 2009) of the selective progesterone receptor modulator (SPRM) ulipristal acetate (30 mg as a single dose up to 5 days afterwards) for emergency contraception. Ulipristal combines the safely and user friendliness of the single application levonorgestrel pill with an even higher contraceptive effectiveness. In Germany, LNG 1.5 mg and ulipristal acetate 30 mg have been approved for emergency contraception. Regardless of the choice of the substance, the administration should occur as soon as possible after unprotected sexual intercourse. The postcoital insertion of an IUD is only considered in special cases.     

Emergency contraception: a clinical review

Emergency contraception is defined as a drug or device used to prevent pregnancy after unprotected sexual intercourse (including sexual assault) or after a recognized contraceptive failure. In the United States, 1.5 mg of levonorgestrel, packaged as Plan B, and the Copper T 380A intrauterine device are the most common emergency contraceptives available to women and are effective up to 5 days after unprotected sexual intercourse. In August 2006, Plan B was approved for over-the-counter sale to women aged 18 and older in the United States. It is not yet known whether the increased availability of emergency contraception will decrease unintended pregnancy and induced abortion rates.     

两种低剂量米非司酮用于房事后紧急避孕的临床研究

为探索米非司酮作为紧急避孕的合适剂量,本研究对避孕失败或未避孕同房７２ ｈ 内要求紧急避孕的６６０例妇女,随机单次服米非司酮１０ ｍ ｇ 或２５ ｍ ｇ。结果：１０ ｍ ｇ 组３２１例中妊娠３例,２５ ｍ ｇ 组３３９例中妊娠４例,均明显低于预期妊娠数,组间差异不明显。避孕有效率分别为８８．２４％ 和８３．４３％ ,副反应轻微。两组分别有１４．１５％ 和２１．１９％ 的服药者周期延长３天以上,组间差异显著（Ｐ＜ ０．０５）。本研究提示１０ ｍ ｇ 和２５ ｍ ｇ 两种剂量的米非司酮皆为合适的紧急避孕剂量。对月经的影响而言１０ ｍ ｇ 组优于２５ ｍ ｇ 组。     

小剂量米非司酮用于紧急避孕的研究

目的：探讨一次性小剂量米非司酮25mg用于紧急避孕的效果及可接受性。方法：征集无保护性交或避孕措施失败后72小时内来院就诊的健康发女100例,单次口服米非司酮25mg,服药后按时随访并观察药物副反应及下次月经情况,保证月经复潮前禁欲或采用避孕套避孕。结果：根据Dixon方法计算,预期妊娠数为8．845,实际妊娠数为2例,避孕有效率为77．4％。实际妊娠与预期妊娠相比,有显著差异（P＜0．05）。结论：小剂量米非司酮用于紧急避孕是非常简便、安全、有效的方法。     

Progesterone receptor modulator for emergency contraception: a randomized controlled trial

OBJECTIVE: Compare the efficacy and adverse effects of CDB-2914, a new progesterone receptor modulator, to levonorgestrel for emergency contraception. METHODS: We performed a randomized, double-blinded noninferiority trial, enrolling healthy women seeking emergency contraception within 72 hours of unprotected intercourse. Participants were randomly assigned to receive a single dose of 50 mg of CDB-2914, plus a placebo 12 hours later or two doses of 0.75 mg of levonorgestrel taken 12 hours apart. Follow-up was scheduled 5 to 7 days after the expected onset of the next menstrual period. Posttreatment pregnancy was established by a positive urine test at follow-up and confirmed by quantitative serum beta-hCG. Daily diaries were used from the time of emergency contraception use until next menses to record adverse effects and sexual activity. RESULTS: Product efficacy was evaluable in 775 of CDB-2914 users and 774 of levonorgestrel users. Pregnancies occurred in 7 (0.9%, 95% confidence interval 0.2-1.6%) and 13 (1.7%, 95% confidence interval 0.8-2.6%) women, respectively. Based on the estimated cycle day of unprotected intercourse, 85% and 69% of anticipated pregnancies, respectively, were averted. Nausea was reported by a somewhat greater percentage of CDB-2914 than levonorgestrel users (29% compared with 24%, P=.03), but the distribution of other adverse effects was similar in both groups. Women in both groups experienced considerable variation in menstrual cycle length as compared with their reported individual normal cycle lengths. CONCLUSION: CDB-2914 is at least as effective as levonorgestrel in preventing pregnancies after unprotected intercourse and has a similar side effect profile. LEVEL OF EVIDENCE: I.     

Comparison of three single doses of mifepristone as emergency contraception: a randomised controlled trial

BACKGROUND: This is an analysis of the Australian component of a large World Health Organization multicentre dose-finding study of mifepristone for emergency contraception and the first clinical study of this controversial drug in Australia. AIMS: To compare the effectiveness and side-effects of three single doses of mifepristone taken within 120 h after unprotected coitus as emergency contraception. DESIGN: Double-blind, randomised controlled trial. SUBJECTS AND METHODS: One hundred fifty healthy women with regular menstrual cycles who requested emergency contraception. Participants were allocated randomly to one of the three doses (10, 50 and 600 mg). The primary outcome was confirmed pregnancy, and secondary outcome measures included side-effects and delay in the onset of the next menses. RESULTS: Pregnancy rates for mifepristone 10, 50 and 600 mg were 2.0, 2.1 and 2.1%, respectively, with no significant difference between groups. No major side-effects occurred, except an unpredictable delay in the onset of the next menses. Mifepristone 600 mg caused a significantly longer delay in the onset of the next menses than either the 10 or the 50 mg dose. CONCLUSION: Lowering the dose of mifepristone from 600 to 10 mg did not significantly impair its effectiveness as an emergency contraceptive, and caused less delay in the onset of the next menses. Therefore, a dose as low as 10 mg may be preferable to 600 mg for emergency contraception. This is very much lower than the dose required to terminate a pregnancy.     

Experiences with levonorgestrel in postcoital contraception

To examine levonorgestrel as a postcoital contraceptive, 77 women received an oral dose of 0.4 mg per coitus for 1011 cycles and 27 women were administered 0.75 mg per coitus for 226 cycles. In the first dose group seven women became pregnant (Pearl's index 8.3), while two pregnancies resulted in the second group, one of the latter because of faulty drug intake (uncorrected Pearl's index 10.6; corrected Pearl's index 5.3). Menstrual irregularities (chiefly break-through bleedings and oligomenorrhea) were observed in 84.4% and 88.9% of the women, respectively. The number of cycle disorders increased with increasing intake rate and diminished when the drug was applied in excess of six months. The experiments undertaken to test the mechanisms of action indicated an influence on both cervical factor and endometrium, whereas the occurrence of LH-peaks and biphasic basal body temperature patterns suggested the presence of ovulations. Application of levonorgestrel for postcoital contraception failed to be a reliable routine method of hormonal contraception because of insufficient efficacy and considerable menstrual irregularities. The drug should be administered only after unprotected sexual intercourse as might happen, to women with very low frequency of intercourse, or in periods of reduced fertility.     

EMERGENCY CONTRACEPTION FOR MIDWIFERY PRACTICE

Every year in the United States, there are an estimated 3.5 million unplanned pregnancies with nearly one third of these attributed to contraceptive failures. Despite the availability of effective contraceptive methods, far too many women still experience unwanted pregnancies. It has been estimated that emergency contraception, also referred to as postcoital contraception or “the morning after pill,” can reduce the risk of pregnancy after unprotected intercourse by as much as 75%. When administered within 72 hours of unprotected intercourse, emergency contraception, inhibits implantation of a fertilized ovum. The most common method of emergency contraception, the administration of ethinyl estradiol and dl -norgestrel, was initially described by Yuzpe in 1977. In the past 20 years, multiple studies have demonstrated the effectiveness of commonly prescribed combination oral contraceptives containing ethinyl estradiol and levonorgestrel. For those women in whom estrogen is contraindicated, progestin-only pills or the synthetic androgen Danazol have been used with comparable effectiveness rates. For appropriately selected women, an intrauterine device such as the Paraguard T380A (Ortho Pharmaceuticals, Raritan, NJ) also may be inserted within 5–7 days after unprotected intercourse to reduce the risk of unintended pregnancy. Despite its success and safety, emergency contraception is underused by women and their health care providers. As providers of comprehensive health care, mid-wives should provide patients with accurate information concerning pregnancy prevention. For many women, obtaining emergency contraception is an entry into the health care system and provides them an opportunity to be educated about safer sex practices, contraception, and the importance of regular health screening. Regularly discussing emergency contraception with patients at routine health visits will enable them to participate fully in their health care decisions and diminish the physical, psychological, and societal stressors associated with unplanned pregnancy.     

Emergency contraception--clinical and ethical aspects.

Emergency contraception (EC) consists of either 1.5 mg of levonorgestrel (LNG) in one or two doses, or a combination of LNG with ethinylestradiol, administered for up to 5 days after unprotected intercourse. Clinical studies indicate that LNG alone is more effective and has less side effects. Its effectiveness decreases the longer after coitus it is taken. EC is indicated when there is non-compliance or accidents with the use of regular methods of contraception, or when women have had voluntary or imposed unprotected intercourse. The ethics of providing EC has been questioned by some, arguing that it acts by preventing implantation. Scientific evidence does not support this concept, but shows that EC acts mostly before fertilization. Placing obstacles to the access of EC is unethical as it transgresses the ethical principles of autonomy, non-maleficence beneficence and justice. Far from inducing abortions, EC reduces unwanted pregnancies and prevents abortion.     

米非司酮单独或合并双炔失碳酯用于紧急避孕的临床比较研究

探讨低剂量米非司酮单独或合并双炔失碳酯应用于紧急避孕的临床效果。将避孕失败或无保护性生活后９６ｈ内就诊的２６０例健康妇女随机分为４组,组Ⅰ（６５例）：单次口服米非司酮２５ｍｇ;组Ⅱ（６５例）：单次同时口服米非同酮２５ｍｇ,双炔失碳酯７．５ｍｇ;组Ⅲ（６５例）：单次同时口服米非司酮１０ｍｇ,双炔失碳酯５ｍｇ;组Ⅳ（６５例）：单次口服米非司酮１０ｍｇ。结果显示各组均有一例妊娠,失败率均为１．５４％,避孕有效率４组依次为７６．１５％、７９．３６％、８１．９４％、８１．９５％,各组间差异无显著性（Ｐ＞０．０５）。服药后月经周期改变少,且与服药时间有关,副反应发生比例低。表明单次服用低剂量米非司酮２５ｍｇ或１０ｍｇ都可作为有效紧急避孕方法,米非司酮与双炔失碳酯合用未显示出协同作用。     

The effects of advance provision of emergency contraception on adolescent women's sexual and contraceptive behaviors

CONTEXT: Advance provision of emergency contraception (EC) may increase timely access and improve effectiveness, but the impact on adolescent sexual and contraceptive behaviors is not known. OBJECTIVE: To determine whether adolescents given advance EC have higher sexual and contraceptive risk-taking behaviors compared to those obtaining it on an as-needed basis. DESIGN AND SETTING: Randomized trial conducted at urban, hospital-based adolescent clinic in Pittsburgh, PA, from June 1997 to June 2002. PARTICIPANTS: 301 predominantly minority, low-income, sexually active adolescent women, age 15-20 years, not using long-acting contraception. INTERVENTIONS: Advance EC vs instruction on how to get emergency contraception. OUTCOME MEASURES: Self-reported unprotected intercourse and use of condoms, EC, and hormonal contraception ascertained by monthly 10-minute telephone interviews for 6 months post-enrollment. Reported timing of EC use after unprotected intercourse. RESULTS: At both 1- and 6-month followup interviews, there were no differences between advance EC and control groups in reported unprotected intercourse within the past month or at last intercourse. At 6 months, more advance EC participants reported condom use in the past month compared to control group participants (77% vs 62%, P=0.02), but not at last intercourse (advance EC 83% vs control 78%, P=0.34). There were no significant differences by group in hormonal contraception use reported by advance EC or control groups in the past month (44% vs 53%, P=0.19) or at last intercourse (48% vs 58%, P=0.20). At the first followup, the advance group reported nearly twice as much EC use as the control group (15% vs 8%, P=0.05) but not at the final followup (8% vs 6%, P=0.54). Advance EC group participants began their EC significantly sooner (11.4 hours vs 21.8 hours, P=0.005). CONCLUSIONS: Providing advance EC to adolescents is not associated with more unprotected intercourse or less condom or hormonal contraception use. In the first month after enrollment, adolescents provided with advance EC were nearly twice as likely to use it and began EC sooner, when it is known to be more effective.     

Advance provision of emergency contraception for pregnancy prevention: a meta-analysis

OBJECTIVE: Advance provision of emergency contraception can circumvent some obstacles to timely use. We performed a meta-analysis to summarize randomized controlled trials evaluating advance provision of emergency contraception to explore effects on pregnancy rates, sexually transmitted infections, and sexual and contraceptive behaviors. DATA SOURCES: In August 2006, we searched CENTRAL, EMBASE, POPLINE, MEDLINE, a specialized emergency contraception article database, and contacted experts to identify published or unpublished trials. METHODS OF STUDY SELECTION: We included randomized controlled trials comparing advance provision to standard access, defined as any of the following: counseling (with or without information about emergency contraception) or provision of emergency contraception on request at a clinic or pharmacy. TABULATION, INTEGRATION AND RESULTS: Two reviewers independently assessed study quality. We performed a meta-analysis using Review Manager software. Eight randomized controlled trials met inclusion criteria, representing 6,389 patients in the United States, China, and India. Advance provision did not decrease pregnancy rates, despite increased use (single use, odds ratio [OR] 2.52, 95% confidence interval [CI] 1.72-3.70; multiple use: OR 4.13, 95% CI 1.77-9.63) and faster use (weighted mean difference -14.6 hours, 95% CI -16.77 to -12.4 hours). Advance provision did not increase rates of sexually transmitted infections (OR 0.99, 95% CI 0.73-1.34), unprotected intercourse, or changes in contraceptive methods. Women who received emergency contraception in advance were as likely to use condoms as other women. CONCLUSION: Advance provision of emergency contraception did not reduce pregnancy rates and did not negatively affect sexual and reproductive health behaviors and outcomes compared with conventional provision. LEVEL OF EVIDENCE: III.     

米非司酮用于紧急避孕600例临床观察

探讨小剂量米非司酮150mg、50mg及25mg应用于紧急避孕的效果.对避孕失败或无避孕措施的性交后72h内就诊的健康妇女6o0例,随机分成3组.Ⅰ组:单次口服米非司酮150mg.Ⅱ组:单次口服米非司酮50mg.Ⅲ组:单次口服米非司酮25mg.结果:Ⅰ组200例.3例妊娠.Ⅱ组200例,4例妊娠.Ⅲ组200例,3例妊娠.均明显低于预期妊娠数(3组相应预期妊娠数分别为17.O30、15.000、14.868),两者之间存在显著差异(P<0.01).避孕有效率Ⅰ组为82.3%、Ⅱ组为73.3%、Ⅲ组为79.8%,3组之间无显著差异.服药后下次月经周期的改变,3组中以Ⅰ组变化较大;Ⅱ、Ⅲ组变化较小,Ⅰ组与Ⅱ、Ⅲ组之间存在显著差异(P<0.01),但3组总共有80.3%月经周期无改变,从总体上看对月经影响较少.仅有4.8%的人有轻微的副反应.表明150mg、50mg或25mg米非司酮作为性交后72h内的紧急避孕是有效的.建议用25mg米非司酮作为紧急避孕药.     

Postcoital contraception

Since 1979, Pro Familia, the German Association for Family Planning and Sexual Counselling, has offered a postcoital contraceptive program utilizing either the ethinyl estradiol (EE)-norgestrel combined oral contraceptive (OC) described by Yuzpe in Canada or a levonorgestrel-only regime. In the Yuzpe method, 4 pills each containing .05 mg EE and .5 mg norgestrel are taken, 2 in the 48 hours following the unprotected coitus and the other two 12 hours later. The other method requires that .6 mg of levonorgestrel be taken in the 12 hours following coitus. In 737 cases of administration of postcoital contraceptives in 26 Pro Familia clinics over the past 3 years, 85% of women were under 28 years old and almost 30% were 14-18 years old. The reasons for utilizing a postcoital method varied but were mostly related to the user, such as nonuse of contraception or forgetting of pills. 25% initiated treatment 1-12 hours after the unprotected intercourse, 44% 13-24 hours later, 27% 25-48 hours later, and 4% 49 or more hours later. In 1% of cases the timing was unknown. 54 patients were treated on cycle days 1-9, 435 on days 10-18, 178 on days 19-27, 37 on day 28 or later, and for 22 the cycle day was unknown. 16 intrauterine pregnancies and no tubal pregnancies occurred. The 522 patients receiving the combined OC treatment had 10 pregnancies for a failure rate of 1.9% and the 205 receiving the progestin-only treatment had 6 pregnancies, for a failure rate of 2.9%.