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The Buddy System: Effectiveness Rates for Backing Up Your Birth Control With a Second Method

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You already know that no method of contraception is 100% effective to prevent pregnancy when you're engaging in sexual activity which presents a risk of pregnancy. You probably also know, however, that there are reliable methods which are very effective when used properly, and that if you use contraception correctly and consistently, pregnancy becomes a whole lot less likely. But did you know that by doubling up and using two methods, with almost any combination you use, you can get mighty close to that 100% with many combos?

Hormonal methods of contraception are currently the most effective, reversible methods of birth control with perfect use. But with most of them, we can goof up -- maybe we skipped a couple pills or got a new prescription late, maybe we're not so timely about getting our injections or don't have consistent healthcare to get a new one on time, maybe we didn't realize our patch fell off. Oops. But if we're consistently backing up with a secondary method, even if our primary one fails, we're covered. As well, not everyone can use or wants to use a hormonal method: some of us prefer non-hormonal methods or those are our only safe or affordable options. While they aren't as effective in perfect use, if we add a backup method to the mix, we can be just as protected or even more protected from pregnancy as we could be with a more effective single method.

You'll see that some combinations can increase your level of protection substantially, while with other pairs -- especially where user error is a non-issue, like with an IUD or an implant -- the difference is so slight that backing up is just overkill. Regardless, there is no single combination of any two methods here which would leave you with less than 92% effectiveness, and most combinations will bump you up to over 95% protection. The highest combined methods' typical use effectiveness -- condoms paired with an implant - is 99.99% effective, while the lowest -- withdrawal buddied up with spermicide - is 92.17% effective. But no matter how you slice it, adding a second method always bumps up your protection against unwanted pregnancy.

The Caveats: This is a mathematical application. That doesn't mean it's not accurate -- it is, and I've got the migraine and a pile of paper covered with my chicken scratches to prove it -- but it does mean that these rates are arrived at through math, based on the combined effectiveness rates of single methods, not through specific study or clinical trials of the combined methods. The sources of our efficiency rates for single methods can be found on the Birth Control Bingo pages linked for each method.

In some cases, combining any two or more methods may possibly slightly reduce the effectiveness of one in actual use. For example, because oral contraceptive pills thicken cervical mucus, condoms, when not used with additional lubricant, can be more inclined to break due to increased friction. Using withdrawal with condoms may make it more likely to forget to hold the base of the condom and create a condom slip which may not have been as likely to happen without adding withdrawal to the mix. Without specific study on these things, we can't predict how much it may reduce the effectiveness of one method in those cases nor account for that possibility in the math. However, we have only listed combinations of methods which are safe and sound to use together and make for good mates. For instance, it would not be safe to combine Depo-Provera with another hormonal method. The vaginal effects of combining a ring and spermicides could cause a good deal of vaginal irritation . Using more than one condom is something we know makes condoms less effective, not more. Natural family planning can't be combined with oral contraceptives since a person using oral contraceptives no longer has a natural fertility cycle to chart in the first place.

We've also not done the math for using more than two methods. If you are properly and consistently using two reliable methods of contraception, the risk of pregnancy is incredibly small, and adding a third method is not likely to increase your protection by very much. The difference between a combined method that is 99.8% effective with typical use of both and three methods which are 99.78% effective together, for instance, is so small a statistical difference that adding a third method is likely to just be a needless expense and pain in your butt.

Certainly, if you prefer more than two methods, so long as they don't interfere with one another, you can choose to do that, but we'd also encourage you to evaluate your feelings. If two methods with something like a less than 2% chance of pregnancy in typical use -- and that still allows for room when it comes to user error -- still doesn't leave you feeling safe enough, you might want to consider that you're not comfortable enough with the small amount of risk which will always be a part of sexual activities that can result in pregnancy. It would probably be a good idea in that case to revisit your readiness, and either stick with activities which don't carry those risks, or hold off on heterosex (genital intercourse with an opposite-sex partner) until you're feeling more prepared for some small level of risk. When you're so freaked about the possibility of pregnancy that no amount of birth control feels like enough, it's unlikely that even with four methods, that level of anxiety is not going to leave room for actually enjoying the sex you're having (which is the whole point). Your enjoyment is going to be seriously hindered if you're taking a pill, putting in a diaphragm, having your partner put on a condom, using withdrawal and then taking EC. It's ideal and laudable to be smart and to be safe, but if your contraceptive practices start to feel like you're building a bomb shelter in preparation for a nuclear war every time you have sex, you or your partners are probably better off when it comes to your pleasure and mental health to recognize that you're not up to any risk of pregnancy, even a very statistically unlikely one, and to choose to engage in activities where your risks are far lower or nonexistent.

Listings for each single method are alphabetical. The combinations are listed from most to least effective with typical use, since typical use tends to be the most accurate measure for real people in real -- and frequently imperfect -- life. For more information on any of the single methods listed, just click on the links in their titles.


Cervical Barriers (Diaphragm)

94% effective alone with perfect use - 86% effective alone with typical use Cervical Barriers + The Contraceptive Implant = 99.99% effective with perfect use - 99.98% effective with typical use
Cervical Barriers + Intrauterine Devices = 99.99% effective with perfect use - 99.89% effective with typical use
Cervical Barriers + Depo-Provera = 99.98% effective perfect use - 99.58% typical use
Cervical Barriers + Combination OCP ("The Pill") = 99.98% effective with perfect use - 98.88% effective with typical use
Cervical Barriers + The Contraceptive Patch = 99.98% effective with perfect use - 98.88% effective with typical use
Cervical Barriers + Minipills = 99.98% effective with perfect use - 98.6% effective with typical use
Cervical Barriers + Male Condoms = 99.88% effective perfect use - 97.9% effective with typical use
Cervical Barriers + Fertility Awareness = 99.88% effective with perfect use - 97.2% effective with typical use
Cervical Barriers + Female Condoms = 99.7% effective with perfect use - 97% effective with typical use
Cervical Barriers + Emergency Contraception = 99.34% effective with perfect use - 96.5% effective with typical use
Cervical Barriers + Withdrawal = 99.76% effective with perfect use - 96.22% effective with typical use

Spermicides with cervical barriers are not listed because spermicide is supposed to be used with them, so effectiveness rates for barrier methods already include the addition of a spermicide. Since the sponge already contains a spermicide, spermicide was also excluded from combination with the sponge.

Combination Oral Contraceptives ("The Pill")

99.7% effective alone with perfect use - 92% effective alone with typical use Combination OCP + Cervical Barriers = 99.98% effective with perfect use - 98.88% effective with typical use
Combination OCP + Male Condoms = 99.99% effective with perfect use - 98.8% effective with typical use
Combination OCP + The Sponge = 99.97%effective with perfect use - 98.72% effective with typical use
Combination OCP + Female Condoms = 99.98% effective with perfect use - 98.32% effective with typical use
Combination OCP + Emergency Contraception* = 99.97% effective with perfect use - 98% effective with typical use
Combination OCP + Withdrawal = 99.98% effective with perfect use - 97.84% effective with typical use
Combination OCP + Spermicide = 99.94% effective with perfect use - 97.68% effective with typical use

Female Condoms

95% effective with perfect use - 79% effective with typical use Female Condoms + The Contraceptive Implant = 99.99% effective with perfect use - 99.97% effective with typical use
Female Condoms + Intrauterine Devices = 99.99% effective with perfect use - 99.37% effective with typical use
Female Condoms + Depo-Provera = 99.99% effective with perfect use - 99.37% effective with typical use
Female Condoms + Combination OCP = 99.98% effective with perfect use - 98.32% effective with typical use
Female Condoms + The Contraceptive Patch = 99.98% effective with perfect use - 98.32% effective with typical use
Female Condoms + the Vaginal Ring = 99.98% effective with perfect use - 98.32% effective with typical use
Female Condoms + Minipills = 99.98% effective with perfect use - 97.9% effective with typical use
Female Condoms + Cervical Barriers = 99.7% effective with perfect use - 97% effective with typical use
Female Condoms + the Sponge = 99.55% effective with perfect use - 96.64% effective with typical use
Female Condoms + Fertility Awareness = 99.9% effective with perfect use - 95.8% effective with typical use
Female Condoms + Emergency Contraception = 99.45% effective with perfect use - 94.75% effective with typical use
Female Condoms + Withdrawal = 99.8% effective with perfect use - 94.33% effective with typical use
Female Condoms + Spermicide = 99.1% effective with perfect use - 93.91% effective with typical use

Don't forget!The addition of condoms to any method always carries the joint benefit of both allowing men a part in birth control and greatly reducing the risks of sexually transmitted infections.

Male Condoms

98% effective alone with perfect use - 85% effective alone with typical use Male Condoms + The Contraceptive Implant = 99.99% effective with perfect use - 99.99% effective with typical use
Male Condoms + Intrauterine Devices = 99.99% effective with perfect use - 99.88% effective with typical use
Male Condoms + Depo-Provera = 99.99% effective with perfect use - 99.55% effective with typical use
Male Condoms + Combination OCP = 99.99% effective with perfect use - 98.8% effective with typical use
Male Condoms + The Contraceptive Patch = 99.99% effective with perfect use - 98.8% effective with typical use
Male Condoms + the Vaginal Ring = 99.99% effective with perfect use - 98.8% effective with typical use
Male Condoms + Minipills = 99.99% effective with perfect use - 98.5% effective with typical use
Male Condoms + Cervical Barriers = 99.88% effective perfect use - 97.9% effective with typical use
Male Condoms + the Sponge = 97.7% effective with perfect use - 97.6% effective with typical use
Male Condoms + Fertility Awareness = 99.96% effective with perfect use - 97% effective with typical use
Male Condoms + Emergency Contraception = 99.78% effective with perfect use - 96.25% effective with typical use
Male Condoms + Withdrawal = 99.92% effective with perfect use - 95.95% effective with typical use
Male Condoms + Spermicide = 99.64% effective with perfect use - 95.65% effective with typical use

The Contraceptive Implant (Implanon)

99.9% effective with perfect use - 99.9% effective with typical use The Contraceptive Implant + Male Condoms = 99.99% effective with perfect use - 99.99% effective with typical use
The Contraceptive Implant + Cervical Barriers = 99.99% effective with perfect use - 99.98% effective with typical use
The Contraceptive Implant + Emergency Contraception*= 99.99% effective with perfect use - 99.98% effective with typical use
The Contraceptive Implant + the Sponge = 99.99% effective with perfect use - 99.98% effective with typical use
The Contraceptive Implant + Female Condoms = 99.99% effective with perfect use - 99.97% effective with typical use
The Contraceptive Implant + Withdrawal = 99.99% effective with perfect use - 99.97% effective with typical use
The Contraceptive Implant + Spermicide = 99.98% effective with perfect use - 99.97% effective with typical use

The Contraceptive Patch ("The Patch")

99.7% effective with perfect use - 92% effective with typical use The Contraceptive Patch + Cervical Barriers = 99.98% effective with perfect use - 98.88% effective with typical use
The Contraceptive Patch + Male Condoms = 99.99% effective with perfect use - 98.8% effective with typical use
The Contraceptive Patch + Female Condoms = 99.98% effective with perfect use - 98.32% effective with typical use
The Contraceptive Patch + Emergency Contraception*= 99.97% effective with perfect use - 98% effective with typical use
The Contraceptive Patch + the Sponge = 99.97%effective with perfect use - 98.72% effective with typical use
The Contraceptive Patch + Withdrawal = 99.98% effective with perfect use - 97.84% effective
The Contraceptive Patch + Spermicide = 99.94% effective with perfect use - 97.68% effective with typical use

Depo-Provera ("The Shot")

99.7% effective with perfect use - 97% effective with typical use Depo-Provera + Cervical Barriers = 99.98% effective perfect use - 99.58% typical use
Depo-Provera + Male Condoms = 99.99% effective with perfect use - 99.55% effective with typical use
Depo-Provera + the Sponge = 99.97%effective with perfect use - 99.52% effective with typical use
Depo-Provera + Female Condoms = 99.99% effective with perfect use - 99.37% effective with typical use
Depo-Provera + Emergency Contraception*= 99.97% effective with perfect use - 99.25% effective with typical use
Depo-Provera + Withdrawal = 99.98% effective with perfect use - 99.19% effective with typical use
Depo-Provera + Spermicide = 99.94% effective with perfect use - 99.13% effective with typical use

Fertility Awareness (FAM)

98% effective with perfect use - 80% effective with typical use Fertility Awareness + Cervical Barriers = 99.88% effective with perfect use - 97.2% effective with typical use
Fertility Awareness + Male Condoms = 99.96% effective with perfect use - 97% effective with typical use
Fertility Awareness + the Sponge = 99.82% effective with perfect use - 96.8% effective with typical use
Fertility Awareness + Female Condoms = 99.9% effective with perfect use - 95.8% effective with typical use
Fertility Awareness + Emergency Contraception = 99.78% effective with perfect use - 95% effective with typical use
Fertility Awareness + Withdrawal = 99.92% effective with perfect use - 94.6% effective with typical use
Fertility Awareness + Spermicide = 99.64% effective with perfect use - 94.2% effective with typical use

Intrauterine Devices (IUD)

99.9% effective with perfect use - 99.2% effective with typical use Intrauterine Devices + Cervical Barriers = 99.99% effective with perfect use - 99.89% effective with typical use
Intrauterine Devices + Male Condoms = 99.99% effective with perfect use - 99.88% effective with typical use
Intrauterine Devices + The Sponge = 99.99% effective with perfect use - 99.87% effective with typical use
Intrauterine Devices + Female Condoms = 99.99% effective with perfect use - 99.83% effective with typical use
Intrauterine Devices + Emergency Contraception* = 99.99% effective with perfect use - 99.8% effective with typical use
Intrauterine Devices + Withdrawal = 99.99% effective with perfect use - 99.78% effective with typical use
Intrauterine Devices + Spermicide = 99.98% effective with perfect use - 99.77% effective with typical use

Minipills

99.7% effective with perfect use - 90% effective with typical use Minipills + Cervical Barriers = 99.98% effective with perfect use - 98.6% effective with typical use
Minipills + Male Condoms = 99.99% effective with perfect use - 98.5% effective with typical use
Minipills + The Sponge = 99.97% effective with perfect use - 98.4% effective with typical use
Minipills + Female Condoms = 99.98% effective with perfect use - 97.9% effective with typical use
Minipills + Emergency Contraception* = 99.97% effective with perfect use - 97.5% effective with typical use
Minipills + Withdrawal = 99.99% effective with perfect use - 97.3% effective with typical use
Minipills + Spermicide = 99.95% effective with perfect use - 97.1% effective with typical use

Spermicide

82% effective with perfect use - 71% effective with typical use Spermicide + The Contraceptive Implant = 99.98% effective with perfect use - 99.97% effective with typical use
Spermicide + Intrauterine Devices = 99.98% effective with perfect use - 99.77% effective with typical use
Spermicide + Depo-Provera = 99.94% effective with perfect use - 99.13% effective with typical use
Spermicide + Combination OCP = 99.94% effective with perfect use - 97.68% effective with typical use
Spermicide + The Contraceptive Patch = 99.94% effective with perfect use - 97.68% effective with typical use
Spermicide + Minipills = 99.95% effective with perfect use - 97.1% effective with typical use
Spermicide + Male Condoms = 99.64% effective with perfect use - 95.65% effective with typical use
Spermicide + Fertility Awareness = 99.64% effective with perfect use - 94.2% effective with typical use
Spermicide + Female Condoms = 99.1% effective with perfect use - 93.91% effective with typical use
Spermicide + Emergency Contraception = 98% effective with perfect use - 92.75% effective with typical use
Spermicide + Withdrawal = 99.28% effective with perfect use - 92.17% effective with typical use

The Sponge

91% effective with perfect use - 84% effective with typical use The Sponge + The Contraceptive Implant = 99.99% effective with perfect use - 99.98% effective with typical use
The Sponge + Intrauterine Devices = 99.99% effective with perfect use - 99.87% effective with typical use
The Sponge + Depo-Provera = 99.97%effective with perfect use - 99.52% effective with typical use
The Sponge + Combination OCP = 99.97%effective with perfect use - 98.72% effective with typical use
The Sponge + The Contraceptive Patch = 99.97%effective with perfect use - 98.72% effective with typical use
The Sponge + Minipills = 99.97% effective with perfect use - 98.4% effective with typical use
The Sponge + Male Condoms = 97.7% effective with perfect use - 97.6% effective with typical use
The Sponge + Fertility Awareness = 99.82% effective with perfect use - 96.8% effective with typical use
The Sponge + Female Condoms = 99.55% effective with perfect use - 96.64% effective with typical use
The Sponge + Emergency Contraception = 99.01% effective with perfect use - 96% effective with typical use
The Sponge + Withdrawal = 99.64% effective with perfect use - 95.68% effective with typical use

The Vaginal Ring

99.7% effective with perfect use - 92% effective with typical use The Vaginal Ring + Male Condoms = 99.99% effective with perfect use - 98.8% effective with typical use
The Vaginal Ring + Female Condoms = 99.98% effective with perfect use - 98.32% effective with typical use
The Vaginal Ring + Emergency Contraception* = 99.97% effective with perfect use - 98% effective with typical use
The Vaginal Ring + Withdrawal = 99.98% effective with perfect use - 97.84% effective with typical use

Withdrawal

96% effective with perfect use - 73% effective with typical use Withdrawal + The Contraceptive Implant = 99.99% effective with perfect use - 99.97% effective with typical use
Withdrawal + Intrauterine Devices = 99.99% effective with perfect use - 99.78% effective with typical use
Withdrawal + Depo-Provera = 99.98% effective with perfect use - 99.19% effective with typical use
Withdrawal + Cervical Barriers = 99.76% effective with perfect use - 96.22% effective with typical use
Withdrawal + Male Condoms = 99.92% effective with perfect use - 95.95% effective with typical use
Withdrawal + Combination OCP = 99.98% effective with perfect use - 97.84% effective
Withdrawal + The Contraceptive Patch = 99.98% effective with perfect use - 97.84% effective
Withdrawal + the Vaginal Ring = 99.8% effective with perfect use - 97.84% effective with typical use
Withdrawal + Minipills = 99.99% effective with perfect use - 97.3% effective with typical use
Withdrawal + the Sponge = 99.64% effective with perfect use - 95.68% effective with typical use
Withdrawal + Fertility Awareness = 99.92% effective with perfect use - 94.6% effective with typical use
Withdrawal + Emergency Contraception = 99.56% effective with perfect use - 93.25% effective with typical use
Withdrawal + Spermicide = 99.28% effective with perfect use - 92.17% effective with typical use

* EC is not advised for frequent use while using other hormonal contraceptives, or unless the primary hormonal method was known or strongly suspected to fail. Since the effectiveness rate for emergency contraception is variable, we have used Plan B, and used the most effective rate (89%) as perfect use and the least as typical (75%). We do not list EC as a sole method of contraception because due to the amount of hormones in oral EC, the expense and the perfect use effectiveness rate being lower than all other methods perfect use rates, it is not intended nor designed for use regularly, nor is sole use as a habit something we advise.

Special thanks to Scarleteen volunteer Courtenay for the math formula and her assistance! Article illustration by Mark Price.

written 01 Jun 2008 . updated 29 Jun 2014

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