Emergency contraception

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Harkesh    on Jun 27, 2011 Says :

Doctors consult is necessary for planned parenthood.
Andrew    on Jun 09, 2011 Says :

All contraceptive methods have some or the other side effects.and chances of failure
abdalla    on May 04, 2011 Says :

very useful for GP to know
john    on Sep 26, 2009 Says :

very usefulto understand
Francesco Pagano    on May 17, 2009 Says :

Very useful to fully understand the argument. A scientific review of great value. Compliments
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  Notes
 
 
Slide 1 : Emergency Contraception Joseph B. Stanford, MD, MSPH University of Utah Department of Family and Preventive Medicine April 2008
Slide 2 : This talk What is emergency contraception? How effective is EC? How does EC work? What should patients be told about EC? The FDA approval process for OTC status of ‘Plan B’ What will be the public health effects of OTC status of ‘Plan B’?
Slide 3 : Disclosures I have never received funding from a pharmaceutical company related to EC. I have scientific and ethical concerns about EC. I believe in honest, balanced research and information for patients.
Slide 4 : What is emergency contraception?
Slide 5 : What is emergency contraception? Contraception after intercourse Yuzpe regimen “Preven” Ethinyl estradiol 100 ?g + levonorgestrel 500 ?g x2 (12 hrs) Levonorgestrel 0.75 mg x2 (12 hrs) or 1.5 mg x1 “Plan B” Mifepristone 10 mg (RU-486) Copper IUD Others in development
Slide 6 : What is emergency contraception? Contraception after intercourse Yuzpe regimen “Preven” Ethinyl estradiol 100 ?g + levonorgestrel 500 ?g x2 (12 hrs) Levonorgestrel 0.75 mg x2 (12 hrs) or 1.5 mg x1 “Plan B” Mifepristone 10 mg (RU-486) Copper IUD Others in development
Slide 7 : History of EC Yuzpe regimen “Preven” First proposed in 1974 =4 pills of most combined oral contraceptives x2 (12 hrs) “Preven” approved by FDA 1998 as prescription; taken off market August 2004 Levonorgestrel 0.75 mg x2 (12 hrs) or 1.5 mg x1 =20 pills of progestin-only contraception x1 “Plan B” approved by FDA 1999 as prescription OTC application 2003, approved August 24, 2006 Mifepristone 10 mg Not yet FDA approved (no time soon)
Slide 8 : How long after? FDA: within 72 hours Advocates: within 120 hours, but more effective with earlier administration, so take as soon as possible. Rationale for OTC or advanced prescription.
Slide 9 : How effective is EC?
Slide 10 : Perfect use and typical use pregnancy rates- EC Perfect use Excludes anyone with additional intercourse after EC use, not completing dose, etc. Typical use All users, all kinds of use
Slide 11 : Perfect use and typical use pregnancy rates- EC WHO 1998 (n=997) Randomized trial of Yuzpe vs. Plan B Perfect use 89% (product promotion) Typical use 85% NOT based on randomization! Based on external comparison of expected pregnancies in historical group
Slide 12 : Randomized trials of EC Unethical to randomize women to placebo Comparison has been another regimen of EC Most often Yuzpe regimen
Slide 13 : How is effectiveness calculated? (E-O)/E = 1- O/E = effectiveness (%) E= expected pregnancies O=observed pregnancies
Slide 14 : WHO 1998
Slide 15 : WHO 1998 RR LNG/Yuzpe = 0.36 (0.18-0.70) Unknown how effective Yuzpe is, or even whether it is effective at all!
Slide 16 : Day-specific probabilities of conception from 2 studies (Dunson et al) Human Reproduction 1999;14:1835-1839. http://humrep.oupjournals.org/cgi/content/full/14/7/1835
Slide 17 : Problem in calculating Expected pregnancies EC studies do not have marker for day of ovulation Usual solution for EC studies: count backwards from end of cycle 14 days and then use probabilities for 6-day window up to and including ovulation
Slide 18 : Problem in calculating Expected pregnancies EC studies do not have marker for day of ovulation Count backwards from end of cycle 14 days and then use probabilities for 6-day window Wrong solution! Ignores normal variation in length of luteal phase (9-18 days)
Slide 19 : Different approaches to calculate expected pregnancies Dixon- adjusts for previous cycle length Trussell- adjusts for previous cycle length (most often used in EC studies) Wilcox- adjusts for luteal length Mikolajczyk and Stanford- adjusts for previous cycle length and luteal length simultaneously
Slide 20 : Biases of different approaches Mikolajczyk and Stanford, Fertil Steril 2005
Slide 21 : Biases of different approaches Depends on window of presentation Studies take women presenting early in cycle Therefore bias with most approaches in most studies is to overestimate EC effectiveness
Slide 22 : How effective is Plan B really? Raymond et al, Contraception 2004
Slide 23 : How effective is Plan B really? 72% typical use Under assumptions of minimal selection bias May be less than this Compare to 89% (7/8) claims for perfect use in package insert and promotional ads Stanford and Mikolajczyk, Curr Rev Wom Health 2006
Slide 24 : How does EC work?
Slide 25 : Early Human Development Fertilization usually occurs in outer third of fallopian tube. Prevent fertilization = contraceptive effect The early embryo implants in the uterus 5-14 days later. Prevent development after fertilization, implantation, or development after implantation but before clinically recognized pregnancy = postfertilization effect
Slide 26 : How does EC work? Before fertilization Prevent ovulation (Prevent sperm migration) After fertilization? Prevent implantation Biologic evidence mixed for LNG Some human studies show endometrial effects Animal studies show no effect after fertilization
Slide 27 : Human follicular ultrasound Croxatto, Contraception 2004
Slide 28 : Human follicular ultrasound Croxatto, Contraception 2004
Slide 29 : How does EC work? Epidemiologic approach Combine probability of ovulation disturbance with probability of conception Fecund window=6 days Delay of administration As time between intercourse and administration of EC increases, so does the probability that conception (fertilization) has occurred before EC was given.
Slide 30 : Plan B effectiveness and mechanism(Based on ovulation and ultrasound data) Mikolajczyk and Stanford, Fertil Steril 2007 With 72, 48, 24, and 0 hours’ delay in administration
Slide 31 : Plan B effectiveness and mechanism(With theoretical maximum prefertilization effects) Mikolajczyk and Stanford, Fertil Steril 2007 With 72, 48, 24, and 0 hours’ delay in administration
Slide 32 : Effectiveness of EC and level of postfertilization effects are directly related. If actual effectiveness turns out to be more than 30-50% with 24 or more hours of delay in administration, then this strong evidence that EC also works after fertilization.
Slide 33 : Effectiveness of EC and level of postfertilization effects are directly related. If EC works at all after 72 hours delay, then it must be working by a postfertilization mechanism.
Slide 34 : What should patients be told about Plan B?
Slide 35 : Plan B: essential counseling points Same hormones present in some birth control pills, in higher dose Used to prevent pregnancy after intercourse More effective the sooner it’s taken Probably not effective after 72 hours Effectiveness- probably no more than 72% Much less than any other method Taking both pills at once is as effective as taking them 12 hours apart
Slide 36 : Plan B: essential counseling points Typical side effects Nausea and vomiting (23%) Abdominal pain (18%) Headache (17%) Fatigue (17%) Delayed or altered menses (26%)
Slide 37 : Plan B: essential counseling points May operate after fertilization (unknown proportion of cycles) =postfertilization effect The more effective it is, the more likely it is operating after fertilization.
Slide 38 : When is conception/pregnancy? “the beginning of pregnancy, usually taken to be the instant that the spermatozoon enters an ovum and forms viable zygote.” -Mosby’s Medical Dictionary, 2002 “...implantation of the blastocyst in the endometrium” -Stedman’s Medical Dictionary, 2000
Slide 39 : Conception and onset of pregnancy Defined differently by different medical authorities. Those who have a particular viewpoint cite one set of authorities and ignore the other set. The more relevant issue is what do patients understand. National polls: about 50% of women believe that “life” begins at conception/fertilization.
Slide 40 : Informed consent Requires that terms be used that clearly communicate to patients’ understandings, beliefs, and values. Insufficient, and potentially misleading to use the word “pregnancy” as beginning at implantation and assume that a patient shares this definition.
Slide 41 : Current marketing of Plan B Package insert “Plan B works like a birth control pill to prevent pregnancy mainly by stopping the release of an egg from the ovary. It is possible that Plan B may also work by preventing fertilization of an egg (the uniting of sperm with the egg) or by preventing attachment (implantation) to the uterus (womb), which usually occurs beginning 7 days after release of an egg from the ovary. Plan B will not do anything to a fertilized egg already attached to the uterus.”
Slide 42 : FDA approval process for OTC status of Plan B
Slide 43 : Abbreviated time line for Plan B July 1999: Plan B approved as prescription Citizen’s petitions for OTC status, state efforts for pharmacist dispensing April 2003: Company applies for OTC status December 2003: FDA Advisory Committee meeting
Slide 44 : FDA hearing Advisory committee for reproductive health drugs: 11 members Advisory committee for OTC drugs: 13 members Special consultants: 4 persons Mix of science, theater, and politics End of day: vote
Slide 45 : FDA Advisory committees vote Final vote for approval for OTC status 23 yes 4 no Stanford: Overestimated effectiveness information and inadequate information for informed consent for postfertilization effects (at time of review) Hager: Insufficient information re OTC safety for adolescents Crockett: Should remain prescription for physician counseling for contraception Cantilena (Chair): Label comprehension studies inadequate
Slide 46 : Abbreviated time line for Plan B May 2004: Against internal advice of staff, the FDA director of CDER denies OTC status, citing (only) concerns about safety of use in adolescents. Investigations begin of decision being made for political reasons July 2004: Company applies for OTC status for women age 16 and older.
Slide 47 : Abbreviated time line for Plan B July 2005: Senators Patty Murray and Hilary Clinton allow the nomination of Lester Crawford as FDA Commission to proceed with promise from HHS Secretary Mike Leavitt that Plan B decision will be made by September 1. August 2005: Susan Wood, Director of FDA Office of Women’s Health, resigns. September 2005: Lester Crawford resigns.
Slide 48 : Abbreviated time line for Plan B Fall 2005: Andrew von Eschenbach nominated for FDA Commissioner; nomination placed on hold by Senators Patty Murray and Hilary Clinton until FDA acts on Plan B OTC application. August 24, 2006: An FDA memo from acting FDA Commissioner Dr. von Eschenbach approves the application of Plan B for OTC status for women age 18 and over- the day before Senate confirmation hearings.
Slide 49 : Conditions for marketing Plan B Only sold in facilities that can sell prescription drugs Sold from behind the counter OTC upon ID proof of 18 and over Company will Engage in educational campaigns for health professionals and public Do annual survey of health professionals Use existing data sources to monitor pregnancy rates, abortion rates, STI rates Monitor point of purchase with anonymous shoppers
Slide 50 : My summary The approval process was amazingly political. The drug meets criteria for OTC safety. Effectiveness is substantially overestimated on product literature and advertising. Company advertising is misleading. What will be the effects of having Plan B more widely available?
Slide 51 : What are the social effects of EC?
Slide 52 : Putative effects of EC Advocates claim great social benefits Prevention of thousands of unplanned pregnancies and related costs Based on number of doses sold, and average number estimated pregnancies that may have occurred if not used Underlying assumption: no other change in sexual and contraceptive behavior Is there any evidence for these claims? Committee on Adolescence, Pediatrics 2005
Slide 53 : Does EC reduce unplanned pregnancy or abortions? RCT China, 2000 women Women using condoms, intervention group given EC (mifepristone) Pregnancy rates (1 year) EC group 4.6% Control group 3.9% Women in EC group more likely to use EC Hu et al, Contraception 2005
Slide 54 : Does EC reduce unplanned pregnancy or abortions? Community intervention in Lothian, Scotland (estimated n=85,000) Provided 5 free courses of EC Estimated 17,800 took this offer 45% used EC at least once Abortion rates did not change in relation to neighboring areas of Scotland Glasier et al, Contraception 2004
Slide 55 : Does EC reduce unplanned pregnancy or abortions? RCT n=2117 women in California Ages 15-24 Usual care (clinic access) 8.7% pregnancy rate Pharmacy access 7.1% pregnancy rate Advanced provision 8.0% pregnancy rate Raine et al, JAMA 2005
Slide 56 : Does EC reduce unplanned pregnancy or abortions? RCT n=111 women Ages 14-20 Usual care 18% pregnancy rate (6 months) Advanced provision of Plan B 7% pregnancy rate (6 months) Not statistically significant Belzer et al, J Adolesc Health 2003
Slide 57 : Does EC reduce unplanned pregnancy or abortions? RCT n=111 women Ages 14-20 Usual care 45% “unprotected sex” (12 months) Advanced provision of Plan B 69% “unprotected sex” (12 months) Statistically significant Belzer et al, J Ped Adolesc Gyn 2005
Slide 58 : Does EC reduce unplanned pregnancy or abortions? UK Abortion rates 11 per 1000 women in 1984 EC made OTC in 2001 Hundreds of thousands of doses sold Estimated should prevent about 1/3 of abortions 40 million pounds spent to educate teens Abortion rates 17.8 per 1000 women in 2004 Similar statistics from Sweden Glasier, British Med J; 16 Sep 2006
Slide 59 : Qualitative studies of EC use Pharmacists and patients UK New York City Generally like the idea of EC, but Concerns about decreased use of “regular” contraception Concerns about increased risk taking Bissell et al, Soc Sci Med 2003; Karasz et al Ann Fam Med 2004
Slide 60 : Qualitative studies of EC use “Perhaps we should pay attention to these concerns of physicians, pharmacists, and users with further qualitative and quantitative research on the long-term outcomes of EC provision, rather than simply dismissing all such concerns as irrational moral qualms…” Stanford, letter. Ann Fam Med 2004
Slide 61 : Social effects of EC use “If you are looking for an intervention that will reduce abortion rates, emergency contraception may not be the solution, and perhaps you should concentrate most on encouraging people to use contraception before or during sex, not after it.” Glasier, British Med J; 16 Sep 2006

 


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