Sample Research Topic Brief: Emergency Contraception Options
(updated October 2015)
Criteria
Brief Description
Introduction
Overview/definition • In the United States, approximately half (51%) of pregnancies are
of topic
unintended.1
• Emergency contraception (EC), or postcoital (after sex) contraception, can
prevent pregnancy after unprotected or insufficiently protected sex.
• There are three forms of emergency contraception available in the U.S.: two
oral formulations — ulipristal acetate (30 mg) and levonorgestrel (1.5 mg) —
and the Copper IUD. Emergency contraception pills are the most common
form of EC; the levonorgestrel (LNG) regimen can be taken up to 120 hours
(with reduced efficacy after 72 hours) after unprotected sex and the ulipristal
acetate (UPA) regimen can be taken up to 120 hours after unprotected sex.
The Copper IUD can be inserted within five days after unprotected sex.2
• Oral emergency contraceptive pills can reduce the risk of pregnancy after
each act of unprotected sex; the Copper Intrauterine Device (IUD) can be
used as EC after an act of unprotected sex and then as ongoing
contraception.
Relevance to
• Emergency contraception provides opportunity for prevention of
patient-centered
unintended pregnancy after sex — especially in instances of sexual assault,
outcomes
contraceptive failure, and contraceptive non-use — and for initiation of
ongoing effective contraception for those women who desire it. Some
women may also use EC pills as their primary form of contraception,
especially if they have sex infrequently. In all instances, understanding the
available EC method options is essential.
• Determining which EC method is best for each woman depends on multiple
factors, including efficacy, side effects, cost, accessibility, and desire for
ongoing contraception.
• Emergency contraception is safe and has few associated side effects; it
provides the benefit of prevention of unintended pregnancy.
• Ongoing pregnancy is associated with further health interventions that may
carry health risks, increased health care utilization, and additional costs for
patients and/or the health care system.
Public Health Burden
Recent prevalence
Prevalence of emergency contraceptive pill use in the United States
in populations and
• In the U.S., about one in nine (11% or 5.8 million) sexually experienced
subpopulations
women aged 15–44 used EC pills in 2006–2010, up from 4.2% in 2002 and
less than 1% in 1995. Most women who had ever used oral EC used it once
(59%) or twice (24%); 17% had used it three or more times.3
• Having ever used EC pills was most common among young adult women
aged 20–24 (23%), women who have never married (19%), Hispanic (11%)
or non-Hispanic white women (11%), and increased with educational
attainment. Among women who had ever used EC pills, almost half reported
using it due to fear of method failure (45%) and half reported use due to
unprotected sex (49%).3
• From 2006–2010, 22% of women aged 15–19 had ever used EC pills, up
1
Criteria
Brief Description
from 8% in 2002.4 A survey of teenagers 14–19 who were aware of EC at a
time when they had had unprotected sex found that as many as 48% of
participants reported ever using EC.5
Prevalence of Copper IUD use as emergency contraception
• The Copper IUD as EC is underutilized compared to EC pills due to limited
on-site availability of the device, challenges in providing same-day IUD
insertion, and reimbursement barriers. Lack of provider or patient
awareness, cost, convenience, and patient desire to use the Copper IUD as
EC can influence use of this method.
• Among a sample of contraceptive providers, the vast majority (85%) had
never mentioned the Copper IUD as a method of EC to patients.6
• At one urban practice, 11.0% of EC clients received a Copper IUD when
same-day provision was offered.7 Research among several Planned
Parenthood affiliates has found Copper IUD for emergency contraception
uptake to be between 1 and 16% among EC clients.8
Effects on patients’ • An option for contraception after sex allows women greater autonomy to
quality of life,
prevent pregnancy in cases of sexual assault, contraceptive failure, or nonmorbidity,
use.
mortality, use of
• Effective EC provides protection against unintended pregnancy, which
health care services
increases use of the health care system and may impact health outcomes
and quality of life.
Options for Addressing the Issue
Based on the
Efficacy
literature, what is
LNG:
known about the
• Levonorgestrel (LNG) EC pills are effective when taken within the first 72
relative benefits
hours after unprotected sex but may remain moderately effective up to 5
and harms of the
days after sex; effectiveness decreased over time.9
available
• Pregnancy rate after LNG EC pills use is approximately 2%9,10; however,
management
efficacy may be affected by a woman’s weight and/or BMI and pregnancy
options?
rates stratified by BMI status range from 1.4% to 6%.11
UPA:
• Ulipristal acetate (UPA) EC pills are effective up to 120 hours after sex with
no decreased efficacy in that window.9,12
• Pregnancy rate after UPA EC use is 1.9%12; however, efficacy may also be
affected by weight and/or BMI.
IUD:
• The Copper IUD is effective EC for up to five days, and in some studies,
through 10 days after unprotected sex, and can remain in place as ongoing
contraception for 10–12 years.9 It can be inserted at any point in the
menstrual cycle as long as pregnancy is ruled out.13
• The Copper IUD is the most effective form of EC with a pregnancy rate of
0.09%.2
• The levonorgestrel-releasing IUD is currently under investigation for efficacy
as emergency contraception.9
Weight/BMI:
• LNG EC pills may be less effective in women who are overweight or obese
2
Criteria
Brief Description
and UPA EC pills may be less effective in obese women. However, no
research has been sufficiently powered to establish a threshold weight at
which oral EC would be ineffective.9
• While some data show that the pregnancy rate among women who took
LNG EC pills was significantly associated with higher weight and BMI11,
other data from World Health Organization trials found no association
between weight and pregnancy rate.2
• Some studies suggest a significant increase in pregnancies among obese
women who take UPA EC pills as compared with non-obese women.12
Among obese women, the pregnancy rate was lower among those who took
UPA than those who took LNG EC pills.2
• The efficacy of the Copper IUD for EC is not affected by weight or BMI.9
• Though EC pills are effective at reducing the risk of pregnancy after an act of
unprotected sex, EC has not been effective at reducing unintended
pregnancy at a population level because EC pills are not used every time
they are needed.2 The lack of population-level effects should not negate the
importance of EC pills as an individual-level treatment option to reduce the
risk of pregnancy.
Safety
LNG & UPA:
• There are no contraindications to LNG or UPA emergency contraceptive pills
nor have any deaths or serious complications been linked to LNG or UPA EC
use.9 They have also been found safe for use by adolescents.14
• LNG EC exposure during ongoing pregnancy has not been linked to any
adverse events for the woman or the mental or physical development of
infants exposed. Further, there is no increased risk in ectopic pregnancy
after LNG EC use. Limited data on UPA EC exposure during ongoing
pregnancy shows no teratogenic effects.2,9
IUD:
• The Copper IUD is safe to use as EC and ongoing contraception for most
women, including adolescents. There are few contraindications for use.15
Side Effects
LNG & UPA:
• EC pills have few associated side effects or adverse events. LNG and UPA
EC pills have similar incidence of adverse effects, including headache,
nausea, irregular bleeding, breast tenderness, abdominal pain, dizziness,
and fatigue.9
IUD:
• In addition to discomfort and risks associated with Copper IUD insertion,
some women may experience uterine cramping, increased duration of menstrual flow, or dysmenorrheal.9
Options for ongoing contraception
LNG:
• After taking LNG EC pills, hormonal contraception can begin immediately
3
Criteria
Brief Description
(i.e. “QuickStart”); however abstinence from sex or a barrier method should
be used for the first 7 days.9
UPA:
• UPA is an antiprogestin and could theoretically interact with progestins in
other contraceptives, potentially reducing efficacy for both.2
• There is some evidence to suggest that starting contraception at the same
time as UPA EC could reduce the contraceptive effect of either method.
Based on this, the FDA changed the UPA labeling to include a new warning
about its use with hormonal contraceptives and a recommendation to delay
initiating hormonal contraception until no sooner than 5 days after taking
UPA. However, there have been no clinical studies demonstrating an
increased rate of pregnancy.9
• Therefore, many providers continue to follow The U.S. Selected Practice
Recommendations for Contraceptive Use, 2013, which advises that any
regular contraceptive method can be started immediately after the use of
ulipristal acetate emergency contraception, but the woman should abstain
from sexual intercourse or use a barrier method of contraception for 14 days
or until her next menses, whichever comes first.9
IUD:
• A Copper IUD inserted for EC can provide ongoing contraception for 10–12
years.
Accessibility
LNG:
• In the U.S., EC pills of 1.5 mg of levonorgestrel can be sold over the counter
to women and men, without age restriction, for approximately $40 to $50
on average.2 While insurance plans generally do not reimburse for LNG
when it is sold over the counter, some will reimburse if a prescription is
written.
• Despite being available without age or point-of-sale restrictions, many
pharmacies require that EC-seekers speak with a pharmacist or employee to
access LNG EC, ask for ID, or apply minimum age requirements.16 Improved
access among adolescents has been associated with increased use.14
UPA:
• In the U.S., UPA EC requires a prescription, but is not widely available at
pharmacies. There is an online prescription service available to help with
access. UPA costs approximately $50 (in addition to any consultation fees),
though many insurance plans will cover the cost.2
IUD:
• Obtaining the Copper IUD for EC requires an insertion visit, which has
clinical operations considerations (i.e., clinic capacity, on-site stocking of
devices, and trained clinical staff) and cost considerations (i.e., high upfront
costs and inadequate insurance coverage).2
• Providers may not offer the Copper IUD as an option for all women due to
limited awareness, clinical knowledge, or attitudes about appropriate
candidates (i.e., not offering to women with no previous births).17
• Though the Copper IUD is safe and appropriate for adolescents18,
4
Criteria
What does the
literature tell us
about patient
preferences?
What does the
literature tell us
about provider
preferences?
What could new
Brief Description
adolescents may face barriers accessing this method of EC due to cost or
confidentiality concerns that may cause difficulties in using insurance or
scheduling the insertion appointment. Additionally, providers may be less
likely to recommend or offer IUDs for adolescents.
Knowledge and Awareness of Emergency Contraception
• Several studies have demonstrated that while awareness of EC may be high
among women, they may not have the necessary knowledge to access EC
and use it correctly.19–21 Awareness of the Copper IUD for EC is lower.17
• Knowledge and awareness of emergency contraception among adolescents
is generally low.14 Recent regulatory and age limit changes may lead to
increased awareness of EC methods but may also create confusion about
available options.
• While provider awareness is increasing, there may limited medical
knowledge about EC options.19 One survey of family medicine and OBGYN
providers found that 29% of providers were incorrect about the appropriate
timeframe for use of LNG EC.22 Furthermore, providers may not offer the
Copper IUD due to low awareness or knowledge or due to attitudes about
which women are good candidates for the method.17
• Preference for type of EC may be influenced by patient and provider
knowledge. Familiarity with all methods of EC, especially prior awareness of
the IUD as EC, can influence patient choice of EC method.7,23,24
• Interest in obtaining the copper IUD for EC has been reported as ranging
from 13%–15% among U.S. EC patients.7,25,26 However, the associated high
up-front cost is a barrier; more women were interested if offered for
free.7,25,26 Other factors, such as concern for luteal phase pregnancy or
patient schedule and wait times for IUD placement may also influence
women’s preference for the Copper IUD for EC.7
• Programmatic efforts to increase accessibility of the Copper IUD as EC for
those desiring it have found that uptake ranges from 1%–16% among EC
clients.7,8
• One qualitative study among EC users found that patient preference for EC
method type was influenced by a woman’s relationship status, method cost,
and fear of side effects.17
• A pilot study offering women the Copper IUD or LNG pills for EC found that
patient satisfaction with method choice was significantly higher among the
LNG users than Copper IUD users (95.5% were satisfied or very satisfied
compared with 61.5%).27
• There is limited research on provider preferences for EC method selection.
Provider attitudes that reflect misinformation and bias may influence
provider preference for EC method and, therefore, patient access to
information on all methods.
• A survey of OBGYNs found that some physicians believe that access to EC
may lower use of other contraception, cause sexual activity initiation at a
younger age, or increase number of sexual partners. Only half of physicians
reported offering EC to all eligible women.28
• Research on the efficacy of various EC methods for women of varying
5
Criteria
research contribute
to achieving better
patient-centered
outcomes?
Have recent
innovations made
research on this
topic especially
compelling?
How widely does
care now vary?
Brief Description
weight and BMI could help to ensure that women are matched to effective
methods.
• Further research on effective counseling strategies that address efficacy,
cost, side effects, and other factors identified by patients would likely
increase patient satisfaction with their chosen method and possibly increase
future EC use when it is needed.
• Research providing sufficient evidence to make UPA EC pills available over
the counter without age restriction would improve access to a more
effective method of EC that can be used up to 120 hours without reduced
efficacy.
• Research on integrating same-day Copper IUD provision for EC for
interested women would ensure greater access to the most effective
method of EC while also improving access to ongoing highly-effective
contraception.
• Research on the safety, efficacy, and acceptability of the LNG-releasing IUD
for EC should continue to obtain another option for EC, and one that
provides ongoing contraception.
• Patient-centered outcomes research on EC for routine contraception (e.g.,
for those who have sex infrequently) may also be useful to explore
outcomes for women who will not use other ongoing methods of
contraception due to individual needs and preferences.
• Recent concerns around reduced efficacy of LNG and UPA pills for
overweight and obese women has led to inconsistent regulatory decisions
and substantial confusion in clinical practice.2 Robust evidence on the
efficacy of EC methods among women of varying weight and BMI is needed
to ensure that women are taking the most effective method for them.
Increased awareness of the Copper IUD as an additional (and more
effective) option for EC has increased the need for research to inform
patient and provider health care decisions.
• The provision of EC likely varies widely across individual providers, health
care practices, pharmacies, and states.
• Provider familiarity with EC methods can affect uptake among patients23,24
and there is variation in provider and center capacity to insert Copper IUDs
for EC, depending on clinical capacity and scheduling, availability of
devices, and provider knowledge, attitudes, and training.
• Variation among pharmacies also impacts access to LNG and UPA oral EC.
o Though LNG EC is available over-the-counter without point-of-sale
restrictions, in one survey of pharmacies, half of stores did not stock oral
EC on the shelf and two-thirds of those that did kept it locked in a case or
box that required employee assistance to retrieve it.16
o LNG EC can be purchased by men or women, regardless of age;
nonetheless, some pharmacists or stores request to see ID, have
minimum age requirements, or hesitate to dispense to men.16
o There is wide variation in cost of LNG EC, ranging from $32 to $65 for
the brand-name product and $26 to $62 for the generic.29
o Many pharmacies do not stock UPA EC pills.29 However, an online
prescription service for UPA EC may be helping to expand access.
6
Criteria
Considerations for
disparities
Is there any
research underway
(as indicated by
ongoing trials)?
Evidence of
importance to
various stakeholder
groups
Brief Description
• State laws vary in regard to EC: 18 states and DC require provision of ECrelated services to victims of sexual assault in emergency rooms; 9 states
allow for pharmacist-dispensing of EC without prescription; 4 states require
pharmacies to fill all valid prescriptions; and 1 state requires pharmacists to
fill all valid prescriptions. Nine states have restrictions on EC, such as
exclusion of EC methods from contraceptive coverage mandates and refusal
protections for pharmacies and pharmacists.30
Disparities in access
• Given state variation in EC coverage and pharmacy practices, women in
more restrictive states may have reduced access to all EC methods. These
states likely have more restrictive policies for sexual and reproductive health
services and education more generally; reduced access to EC may
exacerbate existing health disparities.
• LNG EC is the only method that can be accessed directly from a pharmacy,
without a visit to a health care provider; women living in areas with limited
health services may rely more heavily on LNG EC, which is potentially less
effective for some women.
Disparities in unintended pregnancy rates
• Evidence on the effect of weight and BMI on EC efficacy could potentially
reduce unintended pregnancy rates by better matching women with a
method that will be most effective for them. Lower income women and
black women are more likely to be overweight or obese and more likely to
have unintended pregnancies 1,31. If these subpopulations are using a
method of EC that may not be effective, disparities in unintended pregnancy
rates may widen.
• A search was conducted on Clinicaltrials.gov for “Emergency
Contraception” and resulted in 33 relevant trials, of which 22 were
completed, 7 were active or recruiting, and 4 had “Unknown” status.
o Two of the active or recruiting studies focus on the effect of weight or
BMI on EC efficacy and 2 of the active or recruiting studies assess the
LNG-IUD for EC.
• A similar search was conducted on the Agency for Health Research and
Quality (AHRQ) Health Services Research Project database. Of the 8 studies
that were found, 6 were relevant.
• 22 projects resulted from a similar search on the National Institute of
Health’s Project Reporter; 3 were relevant.
• No grants on the topic are currently being funded by PCORI.
• Various health organizations have highlighted a lack of evidence on the
association between weight and BMI and reduced EC efficacy.
• Regulatory bodies in the U.S., Europe, and Canada, have noted insufficient
evidence to change labels in order to caution on reduced efficacy of EC pills
in overweight or obese women.
• Several advocacy groups for patients and providers have called for greater
EC access and for clearer guidance on efficacy of EC for overweight and
obese women.
7
Criteria
How likely is it that
a new CER on this
topic would
provide better
information to
guide clinical
decision making?
Brief Description
• Comparative effectiveness research on the efficacy of LNG, UPA, and the
Copper IUD for EC in preventing pregnancy among women of various
weights and body sizes could help guide clinical decision making for
clinicians and patients.
• Comparative effectiveness research on the side effects of EC methods may
be useful to provide women with necessary information to select an EC
method.
• Comparative effectiveness research on the interaction between UPA and
progestin-containing contraceptives, as well as the optimal timing for
initiating progestin-containing contraceptives after using UPA, would be
useful to inform clinical decision making about ongoing contraception.2
Potential for New Information to Improve Care and Patient-Centered Outcomes
What are the
Facilitators
facilitators and
• There is strong desire for evidence on the efficacy of EC methods for women
barriers that would
with higher weight and BMI among the clinical community. Multiple
affect
societies governing practice have been aware of and focused on this issue in
implementation?
recent years and would likely update practice guidelines given more
conclusive findings.
How likely is it that
the results of new
research would be
quickly
implemented into
practice?
Would new
information from
patient-centered
CER on this topic
remain current for
several years?
Barriers
• Visiting a health care provider is not required for all methods of EC; this
presents a challenge to the medical community, which relies on clinical visits
to reach and educate patients. Bypassing a provider visit also presents an
opportunity to improve access beyond women who receive health care
through a provider.
• Various operational practices and policies present barriers to equal access
for all emergency contraceptive methods, including: variations in state and
pharmacy policies, differential insurance practices, availability of UPA
through prescription only and inconsistent stocking practices, provider
knowledge of or attitudes about EC methods, integrating same-day Copper
IUD provision for EC into clinical practice, and substantial cost differences
between EC methods.
• New information on the effect of weight or BMI on EC efficacy would likely
be implemented into practice rapidly, as there is a stated desire for clinical
guidance.
• It is unclear whether counseling/education strategies that emphasize patient
preference and satisfaction when selecting a method of EC would be
implemented quickly.
• Research on the comparative effectiveness of EC methods would likely
remain current for several years. As new EC methods are developed,
rigorous comparative effectiveness research studies would need to compare
the new method to existing methods.
8
1.
Finer LB, Zolna MR. Shifts in intended and unintended pregnancies in the United States, 2001-2008. Am J Public
Health. 2014;104 Suppl :S43-S48. doi:10.2105/AJPH.2013.301416.
2.
Raymond EG, Cleland K. Clinical practice. Emergency contraception. N Engl J Med. 2015;372(14):1342-1348.
doi:10.1056/NEJMcp1406328.
3.
Daniels K, Jones J, Abma J. Use of emergency contraception among women aged 15-44: United States, 20062010. NCHS Data Brief. 2013;(112):1-8.
4.
Martinez GM, Abma JC. Sexual Activity, Contraceptive Use, and Childbearing of Teenagers Aged 15-19 in the
United States. NCHS Data Brief. 2015;(209):1-8.
5.
Rubin AG, Gold MA, Kim Y, Schwarz EB. Use of emergency contraception by US teens: effect of access on
promptness of use and satisfaction. J Pediatr Adolesc Gynecol. 2011;24(5):286-290.
doi:10.1016/j.jpag.2011.03.013.
6.
Harper CC, Blum M, de Bocanegra HT, et al. Challenges in translating evidence to practice: the provision of
intrauterine contraception. Obstet Gynecol. 2008;111(6):1359-1369. doi:10.1097/AOG.0b013e318173fd83.
7.
Schwarz EB, Papic M, Parisi SM, Baldauf E, Rapkin R, Updike G. Routine counseling about intrauterine
contraception for women seeking emergency contraception. Contraception. 2014;90(1):66-71.
doi:10.1016/j.contraception.2014.02.007.
8.
Kohn JE, Nucatola D. EC4U: Results from a Pilot Project to Integrate the Copper IUC into Emergency
Contraceptive Care. Contraception. 2016 Jul;94(1):48-51. doi: 10.1016/j.contraception.2016.02.008..
9.
ACOG. Practice Bulletin Number 152: Emergency Contraception. Obstet Gynecol. 2015;126(3):e1-e11.
10.
Glasier AF, Cameron ST, Fine PM, et al. Ulipristal acetate versus levonorgestrel for emergency contraception: a
randomised non-inferiority trial and meta-analysis. Lancet (London, England). 2010;375(9714):555-562.
doi:10.1016/S0140-6736(10)60101-8.
11.
Kapp N, Abitbol JL, Mathé H, et al. Effect of body weight and BMI on the efficacy of levonorgestrel emergency
contraception. Contraception. 2015;91(2):97-104. doi:10.1016/j.contraception.2014.11.001.
12.
Moreau C, Trussell J. Results from pooled Phase III studies of ulipristal acetate for emergency contraception.
Contraception. 2012;86(6):673-680. doi:10.1016/j.contraception.2012.05.012.
13.
Turok DK, Godfrey EM, Wojdyla D, Dermish A, Torres L, Wu SC. Copper T380 intrauterine device for emergency
contraception: highly effective at any time in the menstrual cycle. Hum Reprod. 2013;28(10):2672-2676.
doi:10.1093/humrep/det330.
14.
Statement P. Emergency Contraception. Pediatrics. 2012;130(6):1174-1182. doi:10.1542/peds.2012-2962.
15.
Hatcher RA, Trussell J, Nelson A, Cates W, Kowal D, Policar MS. Contraceptive Technology. Vol 20th Revis. Atlanta,
GA: Ardent Media, Inc; 2011.
16.
ASEC. EC on the Shelf : Real-World Access in the OTC Era.; 2014.
17.
Wright RL, Frost CJ, Turok DK. A qualitative exploration of emergency contraception users’ willingness to select
the copper IUD. Contraception. 2012;85(1):32-35. doi:10.1016/j.contraception.2011.04.005.
18.
Committee opinion no. 539: adolescents and long-acting reversible contraception: implants and intrauterine
devices. Obstet Gynecol. 2012;120(4):983-988. doi:10.1097/AOG.0b013e3182723b7d.
19.
Koyama A, Hagopian L, Linden J. Emerging options for emergency contraception. Clin Med insights Reprod Heal.
2013;7:23-35. doi:10.4137/CMRH.S8145.
20.
Yen S, Parmar DD, Lin EL, Ammerman S. Emergency Contraception Pill Awareness and Knowledge in Uninsured
Adolescents: High Rates of Misconceptions Concerning Indications for Use, Side Effects, and Access. J Pediatr
Adolesc Gynecol. 2015;28(5):337-342. doi:10.1016/j.jpag.2014.09.018.
21.
Salganicoff A, Wentworth B, Ranji U. Emergency Contraception in California: Findings from a 2003 Kaiser Family
Foundation Survey.; 2004.
22.
Dehlendorf C, Levy K, Ruskin R, Steinauer J. Health care providers’ knowledge about contraceptive evidence: a
barrier to quality family planning care? Contraception. 2010;81(4):292-298.
doi:10.1016/j.contraception.2009.11.006.
9
23.
Baird AS, Trussell J, Webb A. Use of ulipristal acetate and levonorgestrel for emergency contraception: a followup study. J Fam Plann Reprod Health Care. 2015;41(2):116-121. doi:10.1136/jfprhc-2013-100733.
24.
Harper CC, Speidel JJ, Drey EA, Trussell J, Blum M, Darney PD. Copper intrauterine device for emergency
contraception: clinical practice among contraceptive providers. Obstet Gynecol. 2012;119(2 Pt 1):220-226.
doi:10.1097/AOG.0b013e3182429e0d.
25.
Turok DK, Gurtcheff SE, Handley E, et al. A survey of women obtaining emergency contraception: are they
interested in using the copper IUD? Contraception. 2011;83(5):441-446.
doi:10.1016/j.contraception.2010.08.011.
26.
Schwarz EB, Kavanaugh M, Douglas E, Dubowitz T, Creinin MD. Interest in intrauterine contraception among
seekers of emergency contraception and pregnancy testing. Obstet Gynecol. 2009;113(4):833-839.
doi:10.1097/AOG.0b013e31819c856c.
27.
Turok DK, Gurtcheff SE, Handley E, Simonsen SE, Sok C, Murphy P. A pilot study of the Copper T380A IUD and
oral levonorgestrel for emergency contraception. Contraception. 2010;82(6):520-525.
doi:10.1016/j.contraception.2010.06.001.
28.
Lawrence RE, Rasinski KA, Yoon JD, Curlin FA. Obstetrician-gynecologist physicians’ beliefs about emergency
contraception: a national survey. Contraception. 2010;82(4):324-330. doi:10.1016/j.contraception.2010.04.151.
29.
ASEC. The Cost of Emergency Contraception: Results from a Nationwide Survey.; 2013.
30.
Guttmacher Institute. State Policies in Brief: Emergency Contraception.; 2015.
31.
Ogden CL, Lamb MM, Carroll MD, Flegal KM. Obesity and socioeconomic status in adults: United States, 20052008. NCHS Data Brief. 2010;127(50):1-8.
10