Abstract
Emergency contraception (EC) may help prevent pregnancy in various circumstances, such as contraceptive method failure, unprotected sexual intercourse, or sexual assault, yet it remains underused. There are 4 approved EC options in the United States. Although ulipristal acetate requires a provider's prescription, oral levonorgestrel (LNG) is available over the counter for women of all ages. The most effective method of EC is the copper intrauterine device, which can be left in place for up to 10 years for efficacious, cost-effective, hormone-free, and convenient long-term primary contraception. Ulipristal acetate tends to be more efficacious in pregnancy prevention than is LNG, especially when taken later than 72 hours postcoitus. The mechanism of action of oral EC is delay of ovulation, and current evidence reveals that it is ineffective postovulation. Women who weigh more than 75 kg or have a body mass index greater than 25 kg/m2 may have a higher risk of unintended pregnancy when using oral LNG EC; therefore, ulipristal acetate or copper intrauterine devices are preferable in this setting. Providers are often unaware of the range of EC options or are unsure of how to counsel patients regarding the access and use of EC. This article critically reviews current EC literature, summarizes recommendations, and provides guidance for counseling women about EC. Useful tips for health care providers are provided, with a focus on special populations, including breast-feeding women and those transitioning to long-term contraception after EC use. When treating women of reproductive age, clinicians should be prepared to counsel them about EC options, provide EC appropriately, and, if needed, refer for EC in a timely manner.
Abbreviations and Acronyms:
BMI (body mass index), EC (emergency contraception), IUD (intrauterine device), LARC (long-acting reversible contraceptive), LNG (levonorgestrel), OR (odds ratio), UPA (ulipristal acetate)CME Activity
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Learning Objectives: On completion of this article, you should be able to (1) list currently available emergency contraception methods, (2) discuss mechanisms of action, adverse effect profile, and availability of emergency contraception, and (3) discuss the relative efficacy of each method in women of varying body mass indices.
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Dr Casey reports grants from Merck, outside the submitted work. The authors discuss off-label/investigative uses(s) of the following commercial product(s)/device(s): ParaGard, TEVA Women's Health, Inc.
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Half of pregnancies in the United States are unintended.
1
Therefore, it is important that women have access to a full range of contraceptive methods, including emergency contraception (EC). Major gynecologic, pediatric, and primary care organizations recommend counseling women at risk of unintended pregnancy about EC.2
, American Academy of Family Physicians Statement of Policy on Contraceptive Advice. American Academy of Family Physicians website. http://www.aafp.org/about/policies/all/contraceptive.html. Accessed March 7, 2015.
3
, 4
, 5
, Well-woman care: assessments and recommendations. The American College of Obstetricians and Gynecologists website. https://www.acog.org/-/media/Departments/Annual-Womens-Health-Care/Primary-and-Preventive-Care-ONLINE.pdf?dmc=1&ts=20160323T1637572589, Accessed March 23, 2016.
6
In the United States, 4 methods are available, including the copper intrauterine device (IUD) and 3 oral methods: levonorgestrel (LNG) 1.5 mg (a progestin-only pill), ulipristal acetate (UPA) 30 mg (a selective progestin receptor modulator), and the Yuzpe regimen (high-dose combined estrogen and progestin oral contraceptives). All EC options can be used within 5 days of intercourse with varying efficacy. Table 1 reviews the different EC options available in the United States. Women of reproductive age seek contraceptive counseling from various providers, including those in primary care and emergency medicine, who need to be facile in prescribing oral EC and referring women for a copper IUD in a timely manner.7
, 8
, 9
Providers should educate patients about contraception, including EC, in routine health visits. Table 2 provides recommendations on how providers may incorporate EC into a routine visit.Table 1Emergency Contraception Methods Available in the United States
| Method | Brand name | Dosage | Timing of use after unprotected sex | Patient accessibility |
|---|---|---|---|---|
| Levonorgestrel single dose | Plan B One-Step: Take action Next choice one dose My way After pill After a EContra EZ | 1.5 mg, one time | Within 72 h for optimal benefit; can be used 120 h postcoitus | Plan B One-Step: over the counter with no age restriction |
| Split dose | Levonorgestrel tablets (generic) Plan B Next choice | 0.75 mg, 2 tablets 12 h apart | Within 72 h for optimal benefit; can be used 120 h postcoitus | All other formulations: behind the counter for patients aged ≥17 y or by prescription for patients aged ≤16 y |
| Ulipristal acetate | ella | 30 mg, one time | Within 120 h | By prescription |
| Copper intrauterine device | ParaGard | Single device inserted | Within 120 h | Needs office visit |
| Combined oral contraceptive (Yuzpe regimen) | Numerous brands available | Need to combine pills to total 100 μg of ethinyl estradiol and either 0.5-1 mg of levonorgestrel or 1 mg of norgestrel, 2 doses 12 h apart | Within 120 h | By prescription |
a Use as soon as possible after unprotected sex.
b Dose can be combined to take 1.5 mg at one time.
c The following formulations of oral contraceptives have been declared safe and effective by the US Food and Drug Administration for emergency contraception: levonorgestrel 0.15 mg/ethinyl estradiol 30 μg; levonorgestrel 0.1 mg/ethinyl estradiol 20 μg; norgestrel 0.5 mg/ethinyl estradiol 50 μg.
Table 2Addressing Emergency Contraception Within a Routine Health Visit
|
Efficacy
The copper IUD is the most effective form of EC, with nearly 100% reported efficacy,
10
though head-to-head EC comparisons are lacking.11
If desired, the copper IUD may then be kept in place for up to 10 years as a long-acting reversible contraceptive (LARC), given its record of safety, convenience, and cost-effectiveness.12
One study13
reported that more than 80% of women using the copper IUD as EC subsequently kept it as primary contraception.Among the oral methods, UPA is the most effective. A randomized controlled trial comparing UPA 30 mg and LNG 1.5 mg found that women treated with UPA had approximately half the number of pregnancies as compared with those treated with LNG (odds ratio [OR], 0.58; 95% CI, 0.33-0.99).
14
Interestingly, in the 1696 women studied, UPA and LNG were similarly effective when used within 72 hours postcoitus with 15 pregnancies in the UPA group and 22 in the LNG group (OR, 0.68; 95% CI, 0.35-1.31). However, beyond 72 hours postcoitus, UPA was more effective at preventing pregnancy, with no pregnancies in the UPA group as compared with 3 in LNG users.14
If UPA is unavailable, LNG is a good alternative because it does not require a prescription. When LNG 1.5 mg is used within 72 hours postcoitus, it prevents at least half of pregnancies that would have occurred without its use.15
The Yuzpe regimen of multiple combined oral contraceptive pills is considered the least effective EC method and is associated with an increased risk of adverse effects, such as nausea, as compared with LNG EC.
16
It consists of 2 doses, 12 hours apart, of 100 μg of ethinyl estradiol plus 0.5 to 1.0 mg of LNG. Because norgestrel contains 2 progestin isomers, one of which is LNG, it may also be used in the Yuzpe regimen at a dose of 1.0 mg of norgestrel with the same dose of ethinyl estradiol. An analysis of 2 randomized controlled trials revealed a substantially lower risk of pregnancy in LNG users than in those taking the Yuzpe regimen (prevented fraction, 0.51; 95% CI, 0.17-0.69).17
However, the Yuzpe regimen may still have a role in limited resource settings in which the more effective EC methods cannot be easily obtained, or for women with ready access to combined oral contraceptives. Women who have had intercourse near the time of ovulation are at higher risk of pregnancy and should be especially encouraged to use more effective EC methods.18
Barriers to Use
Since LNG EC became available over the counter in 2014, this method is more easily available to many women. Nonetheless, some women are unaware of EC availability without a prescription and this, as well as cost, represents ongoing barriers to wider use. In addition, many providers have limited knowledge about EC. In a 2016 study
19
of providers practicing at larger academic institutions, only 13% of emergency medicine, 17% of internal medicine, 23% of pediatric, 26% of family medicine, and 52% of reproductive health care providers reported awareness of UPA as EC. The percentage of providers across specialties who prescribed UPA was even lower: 3% in internal medicine and emergency medicine, 4% to 5% in pediatrics and family medicine, and 14% in reproductive health. The most effective methods, the copper IUD and UPA, can be obtained only via a clinician, and some women may not feel comfortable requesting EC. Thus, it is important that clinicians discuss all EC options with women across the reproductive age spectrum during well-woman, postpartum, and other scheduled visits. Another barrier to EC use in general includes the misconception that EC can cause an abortion. However, oral EC can only prevent or inhibit ovulation and the copper IUD prevents fertilization by affecting sperm viability and function. No studies have reported that EC negatively affects implantation or an established pregnancy.20
, 21
, Emergency Contraceptive Pills: Medical and Service Delivery Guidelines. International Consortium for Emergency Contraception website. http://www.cecinfo.org/custom-content/uploads/2014/01/ICEC_QandAforDecisionmakers_2013.pdf. Accessed February 13, 2016.
22
Furthermore, few providers (15%-16%) recommend a copper IUD for EC.
19
, 23
Provider misconceptions, such as setting requirements for additional visits for screening tests (gonorrhea and chlamydia), insertions during menses only, as well as general lack of comfort with IUD use in nulliparous women and adolescents, continue to challenge the widespread use of the copper IUD.23
, 24
Logistics may present an additional issue, because the copper IUD requires a visit for insertion within 5 days of unprotected coitus.Adverse Effects
Because oral EC has such a short duration of exposure, the usual contraindications to the use of hormonal contraceptives do not apply to EC. In fact, there is no medical condition in which EC is contraindicated.
12
Furthermore, in women with complex medical conditions, the risk of unintended pregnancy often outweighs any potential risks of EC. Common self-limited adverse effects include nausea and change in menstrual patterns.Providers may have concerns about UPA because it is a newer product, approved in the United States in 2010. However, postmarketing surveillance has reported its safety and acceptable adverse effect profile. Levy et al
22
published a review of pregnancies occurring after UPA use in more than 1,400,000 women and found that there was no increased risk of adverse pregnancy outcomes as compared with population norms. The most common adverse effects included nausea, abdominal discomfort, headache, and changes in menstrual bleeding with the next cycle.22
Mechanism of Action
Available evidence suggests that oral EC works by delaying ovulation.
25
, ACOG Committee Opinion. Access to Emergency Contraception. Number 542, November 2012. The American College of Obstetricians and Gynecologists website. www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Health_Care_for_Underserved_Women/Access_to_Emergency_Contraception. Accessed December 9, 2015.
26
Noé et alACOG Frequently Asked Questions #114, Emergency Contraception. The American College of Obstetricians and Gynecologists website. http://www.acog.org/∼/media/For%20Patients/faq114.pdf?dmc=1&ts=20121127T1830130312/. Accessed December 9, 2015.
27
monitored ovulation via ultrasonography and hormonal assays in women taking LNG EC to ascertain ovulation timing in relation to EC. Of those who used EC before ovulation, 16 pregnancies were expected and none occurred. When EC was used on the day of ovulation or after, 8.7 pregnancies were expected and 8 pregnancies occurred. Therefore, LNG EC is ineffective after ovulation, making a postfertilization effect unlikely.27
Novikova et al28
performed a similar study and found that LNG EC was effective when taken before ovulation but had “little or no effect on postovulation events.” The International Consortium for Emergency Contraception21
states that oral EC works by interfering with ovulation by preventing the luteinizing hormone surge, impeding development of a mature follicle, and/or delaying follicular rupture, in addition to other postulated mechanisms such as thickening of the cervical mucus and interfering with transport of the egg or sperm. Ulipristal acetate prevents ovulation even as the LH levels are rising, and the copper IUD primarily interferes with sperm viability and function.Emergency Contraceptive Pills: Medical and Service Delivery Guidelines. International Consortium for Emergency Contraception website. http://www.cecinfo.org/custom-content/uploads/2014/01/ICEC_QandAforDecisionmakers_2013.pdf. Accessed February 13, 2016.
20
Once again, EC is ineffective after implantation and hormonal EC does not appear to confer risk to an established pregnancy or a developing embryo.20
Transitioning From EC to Contraception
If needed, EC can be used more than once in the same month.
20
However, women requiring frequent use of EC should also be counseled about effective methods of ongoing contraception that do not require frequent attention, such as LARC. This includes copper and LNG IUDs, as well as progestin-only contraceptive implants. Also, repetitive use of EC is less effective than ongoing primary contraception.20
The American College of Obstetricians and Gynecologists29
endorses LARC as first-line contraception for women across the reproductive life span. In the Contraceptive CHOICE Project, LARC methods were established to be substantially more effective than contraceptive pills, patch, ring, or depot medroxyprogesterone acetate injection. Furthermore, women were more likely to choose a LARC method when cost was not a factor in decision making.30
The 2013 Centers for Disease Control and Prevention guidelines
31
recommend starting any regular contraception immediately after the use of UPA and LNG EC. However, in 2015, the US Food and Drug Administration updated the package insert for UPA with the recommendation to hold oral contraceptive pills for 5 days after taking UPA. Although there are limited supporting data, the concern about decreased contraceptive efficacy given the antiprogestin properties of UPA prompted this recommendation.Division of Reproductive Health, National Center for Chronic Disease Prevention and Health PromotionCenters for Disease Control and Prevention (CDC)
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
MMWR Recomm Rep. 2013; 62: 1-60
31
Notably, the European Medicines Agency has not changed its package labeling because of the limited available data. Women should understand the importance of avoiding further unprotected intercourse and use reliable barrier contraceptives during the week after EC use. Additional unprotected intercourse after using EC has been found to greatly increase the rate of EC failure.Division of Reproductive Health, National Center for Chronic Disease Prevention and Health PromotionCenters for Disease Control and Prevention (CDC)
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
MMWR Recomm Rep. 2013; 62: 1-60
18
Effectiveness in Women With Elevated Body Mass Index
Available evidence suggests that oral EC may be less effective than copper IUDs in women with a higher body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared). Glasier et al
18
performed a meta-analysis of 2 randomized controlled trials comparing UPA and LNG efficacy. Compared with women with normal BMI, obese women (BMI, ≥30 kg/m2) had the highest risk of pregnancy (OR, 3.60; 95% CI, 1.96-6.53) and overweight women (BMI, 26-29 kg/m2) had 1.5 times higher odds of pregnancy (OR, 1.53; 95% CI, 0.75-2.95).18
In 2015, Kapp et al32
pooled data from 2 large randomized controlled trials and found that pregnancy rates were subtantially higher in LNG EC users weighing more than 75 kg. Thus, for women with a BMI greater than 25 kg/m2, the copper IUD and UPA are preferred as first-line options.20
However, for women who cannot or will not use an IUD or UPA, less effective EC options should be provided to minimize risk of unintended pregnancy.Breast-Feeding Women
Both the American College of Obstetricians and Gynecologists
33
and the World Health Organization34
endorse LNG EC safety in breast-feeding women. It is unknown whether UPA is secreted into human breast milk, raising concerns about its use in breast-feeding women.35
Although the manufacturer does not recommend UPA use in lactating women, the World Health Organization36
has released an update to its EC guidelines stating that UPA benefits outweigh risks in most breast-feeding women. The copper IUD provides an extremely effective and hormone-free option for EC in breast-feeding women.Medical Eligibility Criteria For Contraceptive Use: Fifth Edition—Executive Summary. World Health Organization website. http://www.who.int/reproductivehealth/publications/family_planning/Ex-Summ-MEC-5/en. Accessed January 9, 2016.
Advanced Provision and Counseling
An advanced supply of oral EC is encouraged for women at high risk of unintended pregnancy, because it can increase timely access to EC.
31
Women desiring copper IUD insertion may take oral EC concomitantly, especially if the IUD insertion may be delayed. Most women do not experience nausea or vomiting; thus, routine use of antiemetics is not necessary. However, an antiemetic may be necessary in some circumstances and should be offered when appropriate, especially if the patient is using the Yuzpe regimen.Division of Reproductive Health, National Center for Chronic Disease Prevention and Health PromotionCenters for Disease Control and Prevention (CDC)
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
MMWR Recomm Rep. 2013; 62: 1-60
31
Women who have not had a withdrawal bleed 3 weeks after EC use should undergo a pregnancy test.Division of Reproductive Health, National Center for Chronic Disease Prevention and Health PromotionCenters for Disease Control and Prevention (CDC)
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.
MMWR Recomm Rep. 2013; 62: 1-60
Conclusion
All providers who see women of reproductive age should be prepared to counsel, provide, and appropriately refer for EC. Women are likely to seek care with their primary provider, as well as emergency care providers when they require EC. The copper IUD is the most effective method of EC and has the benefit of providing cost-effective, safe, and convenient long-term contraception. It interferes with sperm viability and function and is also the most effective method in women with an elevated BMI and in those who are breast-feeding. Oral EC delays ovulation and is generally considered ineffective when administered postovulation. Levonorgestrel EC is available without a prescription to women of all ages. Although there are no medical contraindications to any EC and adverse effects are generally minor, women who frequently need EC should be counseled about more efficacious long-term contraception, especially LARC methods. Barrier contraception should be used after EC until long-term contraception can be initiated.
Supplemental Online Material
References
- Unintended pregnancy in the United States: incidence and disparities, 2006.Contraception. 2011; 84: 478-485
American Academy of Family Physicians Statement of Policy on Contraceptive Advice. American Academy of Family Physicians website. http://www.aafp.org/about/policies/all/contraceptive.html. Accessed March 7, 2015.
- Providing quality family planning services: recommendations of CDC and the U.S. Office of Population Affairs.MMWR Recomm Rep. 2014; 63: 1-54
- Emergency contraception.Pediatrics. 2012; 130: 1174-1182
Well-woman care: assessments and recommendations. The American College of Obstetricians and Gynecologists website. https://www.acog.org/-/media/Departments/Annual-Womens-Health-Care/Primary-and-Preventive-Care-ONLINE.pdf?dmc=1&ts=20160323T1637572589, Accessed March 23, 2016.
- ACOG Committee Opinion no. 598: the initial reproductive health visit.Obstet Gynecol. 2014; 123: 1143-1147
- The impact of contraceptive counseling in primary care on contraceptive use.J Gen Intern Med. 2011; 26 ([published correction appears in J Gen Intern Med. 2011;26(7):822. Borrerro, Sonya [corrected to Borrero, Sonya]]): 731-736
- Identifying adolescent females at high risk of pregnancy in a pediatric emergency department.J Adolesc Health. 2012; 51: 171-178
- A pilot study to assess candidacy for emergency contraception and interest in sexual health education in a pediatric emergency department population.Pediatr Emerg Care. 2010; 26: 413-416
- The efficacy of intrauterine devices for emergency contraception: a systematic review of 35 years of experience.Hum Reprod. 2012; 27: 1994-2000
- Interventions for emergency contraception.Cochrane Database Syst Rev. 2008; : CD001324
- U.S. Medical Eligibility Criteria for Contraceptive Use, 2010.MMWR Recomm Rep. 2010; 59: 1-86
- Copper T380 intrauterine device for emergency contraception: a prospective, multicentre, cohort clinical trial.BJOG. 2010; 117: 1205-1210
- Ulipristal acetate versus levonorgestrel for emergency contraception: a randomized non-inferiority trial and meta-analysis.Lancet. 2010; 375 ([published correction appears in Lancet. 2014;384(9953):1504]): 555-562
- Estimating the effectiveness of emergency contraceptive pills.Contraception. 2003; 67: 259-265
- Randomised controlled trial of levonorgestrel versus the Yuzpe regimen of combined oral contraceptives for emergency contraception.Lancet. 1998; 352: 428-433
- Minimum effectiveness of the levonorgestrel regimen of emergency contraception.Contraception. 2004; 69: 79-81
- Can we identify women at risk of pregnancy despite using emergency contraception? Data from randomized trials of ulipristal acetate and levonorgestrel.Contraception. 2011; 84: 363-367
- Emergency contraception: a national, multi-specialty survey of clinician knowledge and practices.Contraception. 2016; 93: 145-152
- Practice Bulletin No. 152: emergency contraception.Obstet Gynecol. 2015; 126: e1-e11
Emergency Contraceptive Pills: Medical and Service Delivery Guidelines. International Consortium for Emergency Contraception website. http://www.cecinfo.org/custom-content/uploads/2014/01/ICEC_QandAforDecisionmakers_2013.pdf. Accessed February 13, 2016.
- Ulipristal acetate for emergency contraception: postmarketing experience after use by more than 1 million women.Contraception. 2014; 89: 431-433
- Copper intrauterine device for emergency contraception: clinical practice among contraceptive providers.Obstet Gynecol. 2012; 119: 220-226
- Obstetrician-gynecologists and contraception: practice and opinions about the use of IUDs in nulliparous women, adolescents and other patient populations.Contraception. 2014; 89: 572-577
ACOG Committee Opinion. Access to Emergency Contraception. Number 542, November 2012. The American College of Obstetricians and Gynecologists website. www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Health_Care_for_Underserved_Women/Access_to_Emergency_Contraception. Accessed December 9, 2015.
ACOG Frequently Asked Questions #114, Emergency Contraception. The American College of Obstetricians and Gynecologists website. http://www.acog.org/∼/media/For%20Patients/faq114.pdf?dmc=1&ts=20121127T1830130312/. Accessed December 9, 2015.
- Contraceptive efficacy of emergency contraception with levonorgestrel given before or after ovulation.Contraception. 2011; 84: 486-492
- Effectiveness of levonorgestrel emergency contraception given before or after ovulation—a pilot study.Contraception. 2007; 75: 112-118
- ACOG Practice Bulletin No. 121: Long-acting reversible contraception: implants and intrauterine devices.Obstet Gynecol. 2011; 118: 184-195
- Effectiveness of long-acting reversible contraception.N Engl J Med. 2012; 366: 1998-2007
- U.S. Selected Practice Recommendations for Contraceptive Use, 2013: adapted from the World Health Organization selected practice recommendations for contraceptive use, 2nd edition.MMWR Recomm Rep. 2013; 62: 1-60
- Effect of body weight and BMI on the efficacy of levonorgestrel emergency contraception.Contraception. 2015; 91: 97-104
- ACOG Practice Bulletin No. 112: emergency contraception.Obstet Gynecol. 2010; 115: 1100-1109
- Medical Eligibility Criteria for Contraceptive Use.3rd ed. Department of Reproductive Health and Research, World Health Organization, Geneva2004
- Immunopharmacology of ulipristal as an emergency contraceptive.Int J Womens Health. 2011; 3: 391-397
Medical Eligibility Criteria For Contraceptive Use: Fifth Edition—Executive Summary. World Health Organization website. http://www.who.int/reproductivehealth/publications/family_planning/Ex-Summ-MEC-5/en. Accessed January 9, 2016.
Article Info
Footnotes
Potential Competing Interests: Dr Casey reports grants from Merck , outside the submitted work. The authors discuss off-label/investigative uses(s) of the following commercial product(s)/device(s): ParaGard, TEVA Women's Health, Inc.
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© 2016 Mayo Foundation for Medical Education and Research
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- Emergency Life PreventionMayo Clinic ProceedingsVol. 91Issue 12
- PreviewThe recent article on emergency contraception1 and another procontraception article published earlier in the Proceedings2 justify contraception because of the incidence of “unintended” pregnancies, and both cite the same article in support.3 However, the authors do not mention that the article by Finer and Zolna3 clearly documents that the rate of unintended pregnancies actually increased between the years 2001 and 2006 despite years of massive and well-orchestrated promotion of contraception and an 89% user rate.
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