Emergency contraception: methods and efficacy

Emergency Contraception Use in School-Based Health Centers: A Qualitative Study

STUDY OBJECTIVE

To understand contraceptive behaviors and decision-making in school-based health center (SBHC) female patients who have used emergency contraception (EC).

DESIGN

Qualitative interviews and questionnaires.

SETTING

SBHCs.

PARTICIPANTS

Female adolescents, who self-reported EC use, were recruited from SBHCs.

INTERVENTIONS

Interviews were conducted until thematic saturation was reached on the following themes: reasons for selecting EC, perceived EC efficacy, reasons for use, nonuse, or inconsistent use of nonemergent contraception (NEC), and beliefs surrounding pregnancy risk.

MAIN OUTCOME MEASURES

The team used a modified grounded theory approach and open coding technique to identify common themes. Participants completed a questionnaire to assess demographic information and EC knowledge.

RESULTS

Twenty-eight interviews were completed. Reasons for using EC include not using another contraceptive method, using another method incorrectly, or in combination with another method for added protection. Reasons for EC preference include ease of administration, ease of access, minimal side effects, perceived high efficacy, and because it can be used discreetly. Use of NEC was supported by identifying it as more effective, increased sexual experience and anticipation of sex, belief that excess EC decreases efficacy or is detrimental to health, and social interactions. Participants reported having used EC a mean of 3.5 times. Eighteen of 28 participants (65%) incorrectly believed that EC is 90%-99% effective, and 15 of 28 participants (53%) correctly identified ovulation inhibition as the mechanism of action.

CONCLUSION

EC use is promoted by ease of access and administration, experiencing minimal side effects, and perceived high efficacy. Compliance issues with NEC and condoms and a desire for a discreet contraceptive method support EC use.

Population-based evaluation of the effectiveness of two regimens for emergency contraception

OBJECTIVE

To estimate and compare the effectiveness of the levonorgestrel and Yuzpe regimens for hormonal emergency contraception in routine clinical practice.

METHODS

A retrospective population-based study included women who accessed emergency contraceptives for immediate use prescribed by community pharmacists in British Columbia, Canada, between December 2000 and December 2002. Linked administrative healthcare data were used to discern the timings of menses, unprotected intercourse, and any pregnancy-related health services. A panel of experts evaluated the compatibility of observed pregnancies with the timing of events. The two regimens were compared with statistical adjustments for potential confounding.

RESULTS

Among 7493 women in the cohort, 4470 (59.7%) received levonorgestrel and 3023 (40.3%) the Yuzpe regimen. There were 99 (2.2%) compatible pregnancies in the levonorgestrel group and 94 (3.1%) in the Yuzpe group (P=0.017). The estimated odds ratio for levonorgestrel compared with the Yuzpe regimen after adjusting for potential confounders was 0.64 (95% confidence interval 0.47-0.87). Against an expected pregnancy rate of approximately 5%, the relative and absolute risk reductions were 56.0% and 2.8%, respectively, for levonorgestrel and 36.7% and 1.8% for the Yuzpe regimen.

CONCLUSION

The levonorgestrel regimen is more effective than the Yuzpe regimen in routine use. The data suggest that both regimens are less effective than has been observed in randomized trials.

Providers' knowledge of, attitude to and practice of emergency contraception

OBJECTIVES

Barriers to widespread use of hormonal emergency contraceptives (EC), such as lack of knowledge and prejudices held by health-care providers, still exist today. This study was initiated to evaluate the knowledge, attitudes and prejudices of family-planning (FP) providers.

METHODS

This survey was conducted in FP units of primary-health-care centers in Istanbul. A total of 180 providers were interviewed in 80 units to whom a questionnaire was administered by face-to-face technique.

RESULTS

One-hundred and fifty-two of the providers stated that they had heard of EC. The correct timing and dose interval of EC were known by 50% of them. The participants held the belief that EC caused abortion (39.4%), and that it was harmful for the fetus (31.1%). Other prejudices were the possibility of increased unprotected sexual intercourse (78.9%) and a tendency for men to give up condom use (75%); female providers were more prejudiced concerning these statements. The providers' tendency towards the provision of counseling was significantly related to their prejudices (p = 0.011, p = 0.033) and to the application rate (p = 0.000). Conclusion Providers need more detailed information about EC. During FP training courses, the providers should be encouraged towards counseling EC which would increase the application rate of the users and decrease their own prejudices.

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.

[Emergency contraception--current trends, possibilities and limitations]

INTRODUCTION

Emergency contraception has been used for over three decades. Indications for emergency contraception are intercourse without contraceptive protection or inadequate application of other contraceptive means. Also, this method is the only way out in situations when sexual intercourse has proceeded not only without protection, but also without voluntary agreement of both partners.

CONTRACEPTION MEANS

Despite of their proven efficiency, it is thought that application of contraception means, even in countries with highly developed systems of health care, is far below optimal. Contemporary studies have pointed out some new posibilities and novel, modified methods of emergency contraception have been proposed. Basic methods of emergency contraception include use of hormonal preparations and postcoital insertion of intrauterine copper devices. Hormonal preparations that are used in emergency contraception are: combined hormonal contraceptive pills, levonorrgestrel and antiprogestin mifepristone. In 1998, the method with levonogestrel only, was indicated by World Health Organization as a "golden standard" in hormonal emergency contraception. The article gives a survey of new trends, possibilities and limitations of modern emergency contraception, with the aim of popularization of this form of contraception in our country.

A multiparametric study of the action of mifepristone used in emergency contraception using the Rhesus monkey as a primate model

Mifepristone is a potent agent used in emergency contraception (EC). In the present study, we examined the contraceptive efficacy of mifepristone used in EC and then, using the model of mifepristone-based EC, we investigated its mechanism of action in the rhesus monkey. Sexually mature females were allowed to cohabitate with male animals from 1600 to 900 h of any one day of days 8-17 of cycle without (Group I; n = 6) and with a single dose of mifepristone (Group II, n = 31, 25 mg per animal, subcutaneous) 72 h postcoitus. Blood samples from all animals of Groups I and II were used to determine the concentrations of estradiol (E), progesterone (P) and chorionic gonadotrophin in peripheral circulation for retrospective analysis of the days of ovulation and blastocyst implantation. Four out of six animals (66.6%) in Group I became pregnant, while all 31 monkeys in Group II failed to establish pregnancy along with marginal changes in serum concentrations of E and P. In the second part of the study, animals were subjected to the same experimental protocol followed by collection of endometrial tissue samples on cycle day 22 from animals of both Group I (n = 6) and Group II (n = 24). Endometrial samples were subjected to morphological analysis including mitotic index, immunohistochemistry for vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), transforming growth factor beta1, estradiol receptor (ER), progesterone receptor (PR), proliferating cell nuclear antigen, placental protein 14 (PP 14) and detection of apoptosis by terminal nick end labeling method followed by histometric analysis. The results were retrospectively analyzed between the two groups on the basis of the day of treatment after ovulation: early luteal phase (days 0-3 postovulation) and mid-luteal phase (days 4-7 after ovulation). Mifepristone used in EC in the present study resulted in general loss of functional integrity of epithelial compartment characterized by loss of secretory maturation, increased apoptosis and higher degree of degeneration along with decreased expression of VEGF, LIF, PP14 and ER, while PR level increased as compared to control samples. The vascular compartment appeared to be compromised along with affected morphological features and decreased expression of VEGF, LIF, ER and PR following the administration of mifepristone. It appears that mifepristone used in EC alters the physiological homeostasis in epithelial and vascular compartments of implantation stage endometrium rendering it hostile to blastocyst implantation. Furthermore, the degree to which the endometrial function is affected largely depends on the day of mifepristone treatment in a parameter-specific manner resulting in a higher degree of degenerative changes in samples obtained from animals who received mifepristone during mid-luteal phase of cycles.

Scanning electron microscopic (SEM) changes of the endometrium in women taking high doses of levonorgestrel as emergency postcoital contraception

Endometrial surface changes by scanning electron microscope were studied in three women who intentionally took high doses of levonorgestrel as an emergency postcoital contraceptive. Based upon findings of a close link between endometrial receptivity and surface integrity, significant alterations of the uterine lining structure may represent a drug effect accomplishing endometrial contraception. High doses of levonorgestrel (4-6 times more than recommended) caused detectable changes on the surface regardless of the menstrual cycle phase when the medication was taken. Cycle classification was based on estradiol and progesterone hormone levels, which corresponded to the menstrual diary. Comparison to control specimens displayed marked restructuralization of the endometrium. As a main feature, the number of ciliated cells were reduced, and cilia disappeared in the proliferative and periovulatory phase. In the secretory phase, pinopodia disappeared and the endometrial integrity broke down. The contraceptive effect of levonorgestrel seems to be accomplished by alteration of the endometrial surface and, therefore, receptivity.

Provision of Chlamydia trachomatis screening in family planning clinics and emergency contraception in genitourinary medicine clinics: a collaborative cross-speciality survey

Two surveys were undertaken to review (1) provision of Chlamydia trachomatis screening by family planning (FP) clinics in the London region and (2) access to emergency contraception (EC) from genitourinary#10; medicine (GUM) clinics within the former North Thames region. The findings from the first survey suggest that there is insufficient screening (and treatment) in vulnerable groups attending FP clinics. Results#10; from the second survey show that hormonal EC is widely available from within GUM clinics, and those clinics also provide a range of other contraception services. However, these details may not be widely#10; recognised either by policymakers or the general public. #10;

Mifepristone: a potential postcoital contraceptive

Mifepristone is an orally-active progesterone receptor antagonist. When a single dose of mifepristone is given in the mid- or late follicular phase, it may diminish or inhibit the luteinising hormone (LH) surge. In the early luteal phase, a single dose of mifepristone induces significant changes in the endometrium without affecting the hormonal levels or menstruation. When it is given in the mid-luteal phase, there will also be significant changes in the endometrium and some women may have two episodes of vaginal bleeding. A clinical trial suggests that a single dose of mifepristone in the early luteal phase may be an effective contraceptive agent but the lack of a cheap and easy method to identify the LH surge limits its clinical application. The administration of mifepristone alone or in combination with a prostaglandin does not appear to be an effective form of contraception. When used together with a prostaglandin, it may be an effective method for menstrual regulation but the cost and possible side effects of the prostaglandins limit its use. Mifepristone is a very effective method for emergency contraception. The incidence of side effects was also lower than that of the Yuzpe regimen. Lowering the dose of mifepristone from 600 to 10 mg does not decrease its efficacy but the incidence of delay in onset of the subsequent menses is reduced. Despite its efficacy, the reputation of mifepristone as an abortion pill may limit its access in many countries.

Levonorgestrel-only emergency contraception: real-world tolerance and efficacy

Levonorgestrel-only emergency contraception was introduced onto the market in France in May 1999 on the heels of a large-scale clinical trial demonstrating its enhanced efficacy and tolerance over the combined estrogen-progestin reference method. To evaluate the product's real-world tolerance and efficacy in the more than 20 months that it has been on the market, a retrospective study was performed among large-scale prescribers in France. One hundred physicians were asked to complete a written questionnaire outlining their practices with regards to their prescription of the product as well as their knowledge and evaluation of the product's tolerance and efficacy. Results from 82 respondents representing over 2,000 administrations demonstrate that physicians judge levonorgestrel-only emergency contraception to be very well tolerated and without unexpected side effects. Further, respondents report a pregnancy rate similar to that chronicled in the large-scale clinical trial (less than 3%), thus substantiating conclusions regarding the product's considerable efficacy and its potential for reducing the rate of unintended pregnancies.