The Safe Days To Have Sex To Avoid Pregnancy, According To Science

My only married-with-a-baby friends are so cool that they make want to have a baby next week. They have an adorable one-year-old who is even chill at Brooklyn bars (before bedtime). But when it's time for a diaper change, I remember precisely why I'm not ready. Shout out to my IUD, love that thing. Seriously, what would I do without it? Well, maybe just have sex on particular days to avoid pregnancy, which I just learned a lot of women do.

My first thought: Whoa. Brave. Also, these women must not be cynics. I'm such a believer in Murphy's law that I used to take Plan B even when the condom most definitely did not break. (But what if it did?) I've had fully fictional pregnancies despite my three-year relationship with Mirena (my IUD).

Like any curious millennial who's just learned something new, I Googled it, specifically "what "days" are "safe" to have sex on without protection" (air quotes very intended). A less than promising result came in the form of a Newsweek article titled "TRUMP WANTS TO REPLACE BIRTH CONTROL WITH THE DUBIOUS 'CALENDAR METHOD'." Woof.

So what exactly is this "calendar" method? According to Planned Parenthood, it is also called the "rhythm method." It is a "fertility awareness method" or "FAM." FAMs are "ways to track your ovulation so you can prevent pregnancy." Basically, you only have sex on the days you are least likely to get preggers.

Here's a spoiler: Birth control and protection are hands down ONE MILLION TIMES more effective at preventing pregnancy than counting the days in your cycle. (OK, so the "one million" was more for emphasis than sourced from actual science, but there are statistics on the matter.) A page on the U.S. Department of Health and Human Services titled "Fertility Awareness & Natural Family Planning" has some pretty major disclaimers about the method. Of note: "Fertility awareness alone has a one in four chance of leading to an unintended pregnancy." Also: "Of 100 couples that use natural family planning methods, up to 25 women may become pregnant."

Not to be a total mom (because I've been very clear that I'm not ready to be one yet), but I need to say it: BE SAFE. FAMs are very risky. However, when used carefully, it can work. Here are the best days to use the rhythm method:

1. The Days You Are Not Fertile

But what does this even mean? Aren't I always fertile? I am a woman, after all. (Also, why am I so clueless when it comes to my own body?!)

Let's break it down. There are days in your cycle on which you actually cannot get pregnant. These are the days that you are not fertile. According to Planned Parenthood, "the days near ovulation are your fertile days — when you’re most likely to get pregnant." So if you're looking to avoid getting pregnant, fertile (ovulation) days = unsafe, and the others = safe... ish.

Think about it like this: You need a sperm and an egg to meet in order to get pregnant. According to Planned Parenthood:

An egg lives about a day after ovulation and sperm live about six days after sex, [so] you’re basically fertile for around seven days of every menstrual cycle: the five days before you ovulate, and the day you ovulate. You can also get pregnant a day or two after ovulation, but it's less likely.

I definitely don't know when I am ovulating, and thus would have a hard time deciding "OK, let's risk it. It doesn't feel like I'm releasing eggs from my ovaries to my fallopians!" If you are going to use FAMs, you have to be extremely careful about determining which days you are not ovulating/fertile. Which brings me to...

2. The Days You Have Carefully Tracked To Be Sure You Are Not Fertile

Basically, if you're not looking to get pregnant, there is no day that is safe to use FAMs unless you have very carefully researched, tracked, and monitored your cycle. According to the Mayo Clinic: "To use the rhythm method, you track your menstrual history to predict when you'll ovulate. This helps you determine when you're most likely to conceive." Interesting. Also, free. Unfortunately, also not as easy as it sounds.

Planned Parenthood recommends using one or more of the following methods in order to figure out when you are ovulating. There's The Temperature Method, where you quite literally monitor your temperature daily. There's The Cervical Mucus Method, which pretty much has to do with keeping track of your discharge. And there's The Calendar Method, where you count your periods on a calendar.

Additionally, there is The Standard Days Method, which is like The Calendar Method except "you track your menstrual cycle for several months to figure out if your cycle is always between 26 and 32 days long." If your cycle is longer or shorter, you can't use this method. But if your cycle falls within the 26 to 32 day range, "you use another form of birth control (or don’t have vaginal sex) on days 8 to 19, which is when you’re fertile."

However, Planned Parenthood confirms the HHS stats that "FAMs are about 76 percent effective. That means 24 out of 100 couples who use FAMs will have a pregnancy each year." That's a pretty big risk, for a pretty short reward (though everyone loves a good orgasm).

If you decide to try FAMs, make sure you consult with a nurse or doctor who can better help you understand how to track your cycle. Ask yourself if you are up for disciplined daily monitoring of your body. There are also apps to help you track as well. Bedsider recommends these in particular.

I'm not here to tell anybody what to do with their bodies, but I do think that FAMs are probably a good method to use in tandem with condoms, or some other birth control if you really don't want to have a baby. I personally forgot a phone call I had this morning that was in both my phone and computer calendars, so I wouldn't trust myself to monitor my cycle, even with an app. If you do opt for the FAM methods, remember to practice safe sex and keep excellent track of your cycles so that you don't end up with a "fam."

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