Birth Control Efficacy Varies During Penis-in-Vagina Sex — Here’s What to Expect

If you’ve had a mishap, like a missed pill, a broken condom, or unprotected sex, you have a few options in the way of emergency contraception (EC). And you have a window of 3 to 5 days to get it.

There are two types available: EC pills (aka “the morning-after pill”) and the copper intrauterine device (IUD).

A copper IUD is the most effective EC when inserted within 5 days after sex, and it’s just as efficient on day 1 as it is on day 5.

Getting an IUD can cost as much as $1,300, but they are free or low cost with many health insurance plans, Medicaid, and other government programs.

EC pills can reduce the risk of pregnancy by up to 95 percent, depending on which one you take. They’re the most popular option, because they’re relatively easy to access and use. There’s a chance you can get them for free if you have health insurance or Medicaid.

Your pill choices include:

• Plan-B One Step (levonorgestrel). Plan B and its generic versions are available without a prescription at pharmacies and clinics. There’s no age restriction, so can you get it without having to show proof of age. These work best when taken within 72 hours (3 days) of having sex, but can be taken up to 5 days after. Plan B generally costs between $40 and $50, and the generic versions typically cost between $11 and $45.
• ella (ulipristal). This is the most effective type of EC pill, especially if you weigh 155 pounds or more, or if you have a BMI of 30 or higher. You can take it up to 5 days after sex, but the sooner you take it, the better. It’s available by prescription only. You can get a prescription from your usual healthcare professional or at a family planning clinic to fill at a local pharmacy. The cost is usually between $40 and $50.

If you think you might have been exposed to an STI

Take a deep breath. Potential exposure to a sexually transmitted infection (STI) can feel scary AF, but there are things you can do.

Early detection and treatment is key. See a healthcare professional about a prescription for PEP, which can reduce the risk of HIV when taken within 72 hours of possible exposure.

Since STIs have different incubation periods, hold off on testing for at least 14 days for reliable results.

Use this handy-dandy chart to see how effective your birth control is and how it measures up to other options. Each type shows the efficacy range from typical use to perfect use.

Some birth control methods are more effective than others. But none are 100 percent, well, outside of abstinence or a surgical option, like vasectomy or having your tubes tied.

Hormonal IUDs and hormonal implants are up there as the most effective forms of reversible birth control at around 99 percent effective. Other forms can be almost as effective, but they need to be used perfectly. (More on that in a minute.)

Your cycle factors in a couple of ways when it comes to birth control.

Let’s be clear: You can technically get pregnant at any stage of your menstrual cycle, though the likelihood fluctuates.

The chances of getting pregnant are lowest while you’re on your period and highest when you’re ovulating.

When it comes to combination birth control pills, your cycle matters, too. To be protected right away, you need to start taking them within 5 days after your period starts. If you start combination pills at any other time in your cycle, you’ll need to take the pill for 7 days before you’re protected.

The only way to hit maximum efficacy of a birth control method is through perfect use. The rate of efficacy drops with typical use.

Perfect use means you’re using it as directed consistently without fail, while typical use is what generally happens IRL with human error factored in. In other words: Sh*t happens, and stats based on typical use are calculated taking that into account.

The only methods where this doesn’t apply are IUDs, the implant, and surgical sterilization.

Here are some examples of what perfect use looks like versus typical use for birth control pills and condoms, which are two of the most popular contraceptive methods.

If you’re on the pill

Perfect use: Taking the pill every single day, at roughly the same time of day (you have a 3 hour window!), and not taking certain antibiotics or other medications that can interfere with it.

Typical use: Sleeping in and taking your pill later than usual or forgetting to take your pill even once.

If you use condoms

Perfect use: Using a condom every single time you have any P and V contact and putting it on exactly as directed on the package *before* it comes into contact with the vaginal opening.

Typical use: Getting hot and heavy and racing to put it on just as you’re about to ejaculate, not leaving a half-inch of empty space at the tip, and not holding the rim of the condom when removing it to prevent spillage.

A missed period is often what makes a person go “hmmm” and suspect they might be pregnant. But there are other early pregnancy symptoms you can watch for. Some of these can come on before a missed period.

Symptoms to watch for:

• spotting (aka implantation bleeding)
• tender, swollen breasts
• fatigue
• frequent need to pee
• aversion to certain foods or smells
• nausea or morning sickness

Resist the urge to hightail it to CVS after getting randy — a pregnancy test won’t detect anything that early.

For the most accurate result, wait until the week after your first missed period. If you’re antsy and just can’t help yourself, at least give it a couple of weeks after the incident. The HCG hormone (also referred to as “the pregnancy hormone”) takes 12 to 15 days to reach a detectable level.

Talk with a healthcare professional right away if you’re concerned about your risk of pregnancy or an STI. Preventive measures, like an EC and PEP, are most effective when used in the first 72 hours — the earlier the better.

Your healthcare professional can also let you know the best time to get STI testing.

Even with typical use, which accounts for the occasional screw-up, most birth control methods are effective at preventing pregnancy.

If you’re not totally confident or have any doubts, throw a secondary method into the mix, like a barrier, or stick to non-penetrative fun until your birth control’s good to go. (Think: mutual masturbation, erogenous play, oral)

If you’re having trouble being consistent with your current method, consider consulting a healthcare professional to discuss other options.

Adrienne Santos-Longhurst is a Canada-based freelance writer and author who has written extensively on all things health and lifestyle for more than a decade. When she’s not holed-up in her writing shed researching an article or off interviewing health professionals, she can be found frolicking around her beach town with husband and dogs in tow or splashing about the lake trying to master the stand-up paddle board.