Elsevier

Contraception

Volume 66, Issue 5, November 2002, Pages 305-307
Contraception

Original research article
Official warnings on thromboembolism risk with oral contraceptives fail to inform users adequately

https://doi.org/10.1016/S0010-7824(02)00386-4Get rights and content

Abstract

Following the 1995 “pill scare” relating to the risk of venous thrombosis from taking second- or third-generation oral contraceptives, the Committee on Safety of Medicines (CSM) withdrew their earlier recommended restrictions on the use of third-generation pills and published recommended wording to be used in patient information leaflets. However, the effectiveness of this wording has not been tested. An empirical study (with 186 pill users, past users, and non-users) was conducted to assess understanding, based on this wording, of the absolute and relative risk of thrombosis in pill users and in pregnancy. The results showed that less than 12% of women in the (higher education) group fully understood the absolute levels of risk from taking the pill and from being pregnant. Relative risk was also poorly understood, with less than 40% of participants showing full understanding, and 20% showing no understanding. We recommend that the CSM revisit the wording currently provided to millions of women in the UK.

Introduction

Controversy over the risk of venous thrombosis with third-generation oral contraceptives (OCs) has continued since the original “pill scare” in 1995. At that time, a Committee on Safety of Medicines (CSM) warning that they were associated with “around twice the risk,” compared with second-generation preparations, led to a dramatic decrease in use and a rise in pregnancies and terminations [1], which was exacerbated by intensive (and unbalanced) media coverage. The root of the problem was information mismanagement [2], but the focus subsequently has been on assessing the nature of risk, rather than determining how best to communicate this information to users.

OCs are the most popular form of reversible contraception around the world, with recent studies suggesting that 80% of women use OC at some time between the ages of 18 and 24 [3]. They were the first drugs in the UK to have compulsory and comprehensive patient information leaflets supplied with the pack in the 1970s and 1980s (in common with the US). Thus, there has been ample opportunity to assess the effectiveness of such leaflets, yet little in the way of empirical evaluation has taken place (although an in-house leaflet has been tested [4]).

Given the widespread usage, one might expect people to have a good understanding of the risks involved. However, recent research has shown that even relatively well educated women (university students) were “woefully uneducated about the side effects of OC” [3]. This is a particular concern given that failure to read and understand the written information currently provided with OC has been shown to be a major factor in relation to their inconsistent use [5], [6].

In 1999, the CSM withdrew their earlier recommended restrictions on the use of third-generation OC and published written information for manufacturers to include in Patient Information Leaflets that accompany all medicines [7]. This stated that the risk is “15 per 100,000 women per year using second-generation pills and 25 per 100,000 women per year for third-generation pills.” However, there has been no published research on the effectiveness of this wording. Indeed, Drife [2] recently noted that there has been little input from prescribers or users, since the scare, despite it being a requirement of the Department of Health that if third-generation products are offered to patients, the risks involved are adequately explained. Thus, the primary purpose of the present study was to assess how users and potential users of OC interpret this wording, which is currently used on the leaflets. A second aim was to assess how understanding is affected by the provision of an explicit statement (not currently in use) of the relative risk of venous thrombosis in OC users compared with in pregnancy.

Section snippets

Materials and methods

Female university students (n = 186), aged 18 to 45, were recruited. Eighty-five (46%) were taking the pill, and a further 50 (27%) had taken it previously but were not current users. All spoke English as their first language. The participants were randomly allocated to one of two experimental groups (with one receiving an additional relative risk statement and one not). They were given a five-page booklet which included the text in Fig. 1. For half of the participants, the additional relative

Results

When asked “What do you think is the probability you would experience thrombosis if you took the pill? State your answer as a percentage,” 21 (11%) gave the correct answer of 0.015%. A similar question about the probability if pregnant resulted in only 22 (12%) answering correctly with 0.06%. In both cases, the majority (80%) produced over-estimations, with 20% and 30% estimating the probability of thrombosis if taking contraceptives, and if pregnant, respectively, as being greater than 10%,

Discussion

Less than 12% of educated women fully understood the absolute levels of risk of thrombosis from taking the pill and from being pregnant, as worded in leaflets currently provided with OC. When asked to estimate the risk as a number out of 100,000 (the wording used in the leaflet), one-third gave incorrect estimates. Understanding of relative risk was also poor, with less than 40% showing a full understanding, and 20% no understanding. The additional explicit statement that risk in pregnancy was

References (10)

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