Does The Rhythm Method Work? Everything You Need To Know About Fertility Awareness

We at Bustle love giving you tips for how to tap into your sexual potential and troubleshoot when things aren’t going your way in the bedroom. But what about finding solutions to those stressful sexual health situations that inevitably crop up when you’re getting down? Emma Kaywin, a Brooklyn-based sexual health writer and activist, is here to calm your nerves and answer your questions. This week’s topic: exactly how the rhythm method works.

Q: I don't like birth control, so my partner and I use the pull out method right now. My cycles are fairly regular (28-30 day range). What I'm wondering is — if I know I'm in the week before my period or I’m on my period, how big of a risk am I taking if he doesn't pull out during those weeks? Is that what people mean when they say the rhythm method?

A: There’s an old joke that goes: “Q: What do you call a couple who uses the rhythm method? A: Parents.” Contrary to this popular belief, the rhythm method can actually workif (and it’s a big if) you really know your body and where you are in your cycle.

Note: I’ll be using the average 28-day cycle timeline for this explanation, but a normal menstrual cycle can be anywhere from 21 to 35 days long, which is a huge range when you’re talking about the possibility of mis-counting resulting in a baby. If you’re using the rhythm method, it’s critical that you know the actual length of your personal cycle (which can change from month to month, because nothing's ever easy).

And actually, it’s probably a good idea to know this regardless of what birth control you’re using, so you know when to expect all your monthly changes.

What Is The Rhythm Method, Exactly?

The rhythm method is also called the calendar method or fertility awareness, because it’s all about knowing when in your cycle you’re able to potentially get pregnant, and when you’re in the not-fertile “safe zone.”

At its core, this method of birth control is where you have unprotected sex — but only during the times that you know the conditions aren’t right for you to get pregnant. Partners deal with the fertile moments differently: some use condoms, others the pulling out method, and some just take a break from sex altogether (called periodic abstinence). If you practice this method correctly, by which I mean perfectly every time, it’s between 95 and 99 percent effective. However, the typical use specs are much lower, at between 76 and 88 percent. So let’s learn how to do it right!

But before we get there, there's something really important to remember: this method of birth control does not protect you against sexually transmitted infections (STIs), which include HIV, syphilis, chlamydia, and gonorrhea. If you are planning to use the rhythm method, get tested with your sexual partner to find out your statuses.

When Am I Fertile?

Humans with female reproductive organs are fertile only a few days out of their menstrual cycle, around the day of ovulation. Your monthly window of fertility can be up to six days. The second-to-last day of this window is the day you ovulate. If you know when in your personal cycle that day is, go to your calendar right now and circle your six-day fertility time frame. It’s okay, I’ll wait.

Now, let’s look at fertility by each week of your cycle:

Week One: Menstruation — [Usually] Not Fertile

Your menstrual cycle starts on the first day of your period, which is when your uterus is shedding its lining. Menstruation generally lasts around three to five days. If your cycle is 20 days or longer (which is most people), you aren't fertile during this time.

However, if you have a very short cycle and you have sex at the tail end of your period, there's a small possibility you can get pregnant.

Week Two: Getting Ready for Ovulation — Fertile

Technically, your body starts readying itself to ovulate on the first day of your cycle, but in week two, your egg is really on its way to becoming mature. During this week, ovulation hasn’t happened yet (it’s on day one of week three, hold your horses).

However, you are fertile during this week. This is because sperm can live in the female reproductive tract for up to five days. So if we’re working off of a 28-day cycle, your window of fertility starts on day nine of your cycle, which is two days into your second week.

Week Three: Ovulation — Fertile

Ovulation actually describes a single moment halfway through your cycle — day 14 in a 28-day cycle. During ovulation, your body releases a mature egg from one of your ovaries into your fallopian tube. There it waits for sperm to come meet up with it, to make a baby. This egg can live in your body for 24 hours, after which point, if it hasn’t connected with a sperm, it disintegrates.

You are fertile on the day you ovulate, and for one day after — until your egg disintegrates.

Week Four: Luteal Phase — Not Fertile

The fourth week of your cycle is called the luteal phase, but you probably know it as the week where you get "premenstrual syndrome,” or PMS. In this week, your body is gearing up for your menstrual cycle again. It’s regrowing your uterine lining and getting ready to shed. You are not fertile at this time.

So, How Do I Know When I’m Ovulating?

If your menstrual cycles aren’t exactly the same number of days each month or you honestly haven’t been paying attention and writing them down on a calendar each month, not to worry. You can learn to read your body so you can tell when you’re ovulating. This can in turn inform you if you’re in or out of your six-day window of fertility.

Check Your Calendar

Arguably the most important tool for the couple using the rhythm method is the good ol’ fashioned calendar. It’s important to track your ovulation patterns over time to assess how regular they actually are — and remind both of you when you need to either abstain or use another form of birth control. And of course, for those modern folks out there, there’s an app for that … many in fact.

The calendar is crucial to the rhythm method because your window of fertility starts up to five days before ovulation — and no thermometer or mucus test gives you a five-day warning. To make sure you have this right, many experts say you should start tracking your cycle patterns for anywhere from six months to a year before you can feel confident enough about your personal cycle calendar to ditch your other methods of birth control.

Check Your Temperature

Your body temperature changes a teeny tiny bit when you ovulate. I’m talking really small differences here — so small that you need a special thermometer, called a basal thermometer. To track changes at this level of specificity, you need to take your temperature first thing every morning. Your temperature dips a tiny bit right before ovulation, and then rises between 0.4 and 0.8 degrees Fahrenheit when you ovulate.

Check Your Cervical Mucus

Around the time of ovulation, your cervical mucus changes consistency, turning clear, slippery, and stretchy — like egg whites. This is to make it easier for sperm to reach their destination. Take a finger dip into your mucus on the daily to see if it’s got that stretchy quality, because that’s a sign you’re fertile. Here's how.

Check Your Ovulation Kit

You can also purchase an ovulation kit, which are kind of like pregnancy kits except they test your urine for the hormones that indicate ovulation, as opposed to tiny human. These kits can be extremely useful in telling you if you’re fertile, but they can also be pretty pricey.

The Bottom Line

I strongly believe that all sex should be based on a solid foundation of open communication between partners, but this is even more the case when you’re using something like the rhythm method. Sure, you may be the one tracking your cervical mucus or taking your temperature every morning, but your lover should know what’s going on too.

If both of you are working toward the same goal of achieving sexual pleasure without progenating, then it really helps for both of you to know all the facts about how close you are to that fertility window. And remember — at the end of the day, this is unprotected sex we're talking about — it's not foolproof.

Images: Mike Hyde/Flickr; Lisa Bass/Bustle, Giphy