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1 Facing Facts (and Lack of Facts) about Effectiveness of ECPs Elizabeth Raymond, MD, MPH James Trussell, PhD Chelsea Polis Obstet Gynecol 109(1):181-188,

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Presentation on theme: "1 Facing Facts (and Lack of Facts) about Effectiveness of ECPs Elizabeth Raymond, MD, MPH James Trussell, PhD Chelsea Polis Obstet Gynecol 109(1):181-188,"— Presentation transcript:

1 1 Facing Facts (and Lack of Facts) about Effectiveness of ECPs Elizabeth Raymond, MD, MPH James Trussell, PhD Chelsea Polis Obstet Gynecol 109(1):181-188, January 2007

2 2 The Hope Widespread use of ECPs could prevent HALF of all unintended pregnancies and abortions in the US each year (Trussell et al., 1992)

3 3 The Reality Eleven studies have examined the impact of increased access to ECPs on pregnancy and abortion rates

4 4 Fourteen Years Later Eleven studies have examined the impact of increased access to ECPs on pregnancy and abortion rates None have shown any benefit

5 5 Agenda Today Review these studies Discuss possible explanations for disappointing findings

6 6 The Eleven Studies Conducted 1998-2006 4 countries Yuzpe, LNG, mifepristone

7 7 The Eleven Studies (continued) 9 randomized trials, 1 cohort study –Total of 11,830 women enrolled 1 demonstration project –>17,831 women given ECPs Followed women up to one year Compared increased access to standard access

8 8 Selected Studies NRegimen 1 Yr Preg. Rates interventioncontrol Glasier1083Yuzpe5%6% Lo1030LNG1%2% Hu2000mife4%3% Raine2117LNG8%9% Raymond1490LNG9%10%

9 9 Explanations 1. Flaws in studies

10 10 Problems with the Studies Small size (160-2868 women) Huge loss to follow-up (1-62%) Weak intervention Good access in comparison group Low baseline risk of pregnancy – little room for improvement with EC Not randomized

11 11 However… None of the 11 studies had all of these problems Indeed, some were very good! Consistency of findings hard to ignore

12 12 Explanations 1. Flaws in studies 2. Increased risk taking

13 13 ECPs and Risk Taking Lots of data None show (almost) any effect of enhanced ECP access on unprotected sex or use of regular contraception Some suggest improved behavior Most data self-reported 2 studies showed no effect on STIs

14 14 Explanations 1. Flaws in studies 2. Increased risk taking 3. Low ECP efficacy

15 15 Current Estimates ECP efficacy conveys the reduction in pregnancy risk after a single coital act Plan B package (LNG regimen): 89% ICEC Service Delivery Guidelines: –LNG regimen 60% - 94% –Yuzpe regimen 56% - 89% (74%)

16 16 Methodology In a group of ECP users, compare: observed number of pregnancies expected number of pregnancies (number that would have occurred without ECPs) Calculate the amount of reduction due to the ECPs

17 17 Example WHO 1998 trial of LNG vs. Yuzpe regimen 1001 women using LNG regimen Pregnancies observed: 11 Pregnancies expected without EC: 75.3 Pregnancies prevented: 75.3 - 11 = 64.3 Efficacy: 64.3 = 85% 75.3

18 18 Example WHO 1998 trial of LNG vs. Yuzpe regimen 1001 women using LNG regimen Pregnancies observed: 11 Pregnancies expected without EC: 75.3 Pregnancies prevented: 75.3 - 11 = 64.3 Efficacy: 64.3 = 85% 75.3

19 19 Expected Pregnancies Collect data on: –date of sex act –date of last menstrual period –usual menstrual cycle length Determine the day of the menstrual cycle when the coital act occurred Use published data to estimate expected pregnancies

20 20 Pregnancy Risk by Cycle Day

21 21 Pregnancy Risk by Cycle Day

22 22 Do Any of the Charts Apply? Women in the charts wanted to be pregnant ECP users wanted NOT to be pregnant Used broken condom, withdrawal Different fertility? Different amount of unprotected sex? Different accuracy in reporting data?

23 23 Results Numbers of expected pregnancies reported by studies are probably too high Most published efficacy figures are probably overestimates

24 24 Dont Give Up… ECPs do work! Physiology studies show effects incompatible with pregnancy LNG regimen proven to be more effective than Yuzpe it must be more effective than nothing

25 25 Efficacy of LNG Regimen

26 26 Efficacy of LNG Regimen

27 27 Explanations 1. Flaws in studies 2. Increased risk taking 3. Low ECP efficacy 4. Insufficient use

28 28 Effects of Increased Access In all studies so far (except one), increased access resulted in substantially increased use But…

29 29 But… Repeated use was uncommon Many unprotected acts remained uncovered by ECPs No ECPs were used in most pregnancy cycles

30 30 Reasons for Non-Use Reasons given by women: Failure to perceive pregnancy risk Forgetting Lack of motivation to use EC (Im lazy) Inconvenience

31 31 Why Didnt You Take Them? Now, my experience is that most of the time, people have no idea why they're doing what they're doing. They have no idea, so they're going to try to make up something that makes sense. - Clotaire Rapaille, Chairman, Archetype Discoveries Worldwide

32 32 Limits on ECP Use Expense Side effects High dose of hormones Psychologic stress

33 33 Ineffective Use Many uses are wasted – ECPs taken at times when risk is really low Does wasted use limit truly needed use?

34 34 Eleven Studies, No Benefit 1. Flaws in studies - but consistency compelling 2. Increased risk taking - no evidence 3. Low ECP efficacy - precise efficacy unknown 4. Insufficient use - definitely a problem

35 35 What To Do Now? Be honest: do not oversell by implying Plan B will reduce unintended pregnancy Everyone deserves a second chance to prevent an unintended pregnancy


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