Many factors that are not related to health, such as convenience and cost, are appropriate
to be considered when choosing a contraceptive. Although currently available
contraceptive technologies have greatly improved the regulation of fertility, for
many women and men, under typical conditions of use, they still have some drawbacks
relating to safety, side effects, and effectiveness. Because some commonly
used contraceptives are much less effective than others in preventing pregnancy,
choosing the best contraceptive for an individual is important.
Contraceptive effectiveness
Studies of unintended pregnancy in the U.S. reveal that many unintended pregnancies
occur because contraceptives are not used, because they are discontinued after
only a short period of use, and because there are gaps in use. An estimated 52%
of the 3.2 million annual unintended pregnancies in the U.S. result from non-use
of contraception, 43% from inconsistent or incorrect use, and only 5% because the
method itself failed when being used correctly.
Reasons for non-use or inconsistent use of contraception include high cost, limited
access, infrequent sexual activity, ambivalence about becoming pregnant, and underestimating
the risk of becoming pregnant. Other prominent reasons for inconsistent
use include dissatisfaction with methods, often after experiencing side effects,
but also because of concerns about safety, worries they might cause unpleasant side
effects, and inconvenience.
When considering which contraceptive to choose, an important distinction must be
made between theoretical effectiveness—when a contraceptive is used perfectly;
and use effectiveness—the effectiveness achieved by a typical or average user. The
permanent contraceptive methods, male and female sterilization, and the LARC
(long-acting reversible contraceptive) methods (IUDs and implants) are highly effective
in preventing pregnancy. Their theoretical and use effectiveness is essentially
identical. But for commonly used methods, including oral contraceptives (OC),
the patch, the ring, injectables (Depo-Provera), and condoms, there is a substantial
difference between their effectiveness in typical use compared to the effectiveness
measured in carefully controlled clinical trials.
One reason there are so many unintended pregnancies in the U.S. is that almost half
of U.S. contraceptive users rely on methods that, in typical use, have both high failure
and high discontinuation rates: the pill, the condom, and the 3-month injectable.
Among teenagers, condoms and withdrawal are the most commonly used methods.
While with perfect use, these methods are highly effective, on average, 9% of
pill users, 18% of condom users, and 6% of injectable users will become pregnant
during the first year of typical use. In a recent study of high-risk teenagers, pregnancy
rates were still higher, with 16% of pill and injectable users becoming pregnant
during their first year of use.
Because they do not require continuing motivation for use, LARCs have
the best one-year continuation rates at 78% for the copper T 380A (ParaGard®),
80% for the LNG-IUS (Mirena®), and 84% for the implant (Nexplanon®).17 Risk
of unintended pregnancy in the U.S. is therefore closely related to both non-use of
contraception and the frequent choice of contraceptive methods that are likely to be
used incorrectly or inconsistently or are likely to be discontinued shortly after they
are adopted.
Another problem is that the effectiveness of the mix of contraceptives in use in the
U.S. is substantially impaired because of high discontinuation rates. About half of
condom and injectable contraception users—and almost one-third of pill users—
will discontinue use within a year, and they may become non-users of contraception.
The figure below presents the failure rates of various methods of contraception.
Risk of pregnancy is lowest among users of the LARCt contraceptive methods
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel.
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