Are You Supposed To Ovulate On The Same Day Every Month? But That Would Be Too Easy

Ad failed to load

Personally, I feel like the human body is missing a few features, and one of them is an ovulation alarm. Wouldn't it be great if instead of temping, charting, or buying ovulation predictor kits (OPKs), a little beep went off in your head? Or your big toe glowed? Or something? Unfortunately, the inner workings of human fertility are often invisible — not to mention complex. Questions abound, and here's an interesting one: considering ovulation follows a cyclical pattern, are you supposed to ovulate on the same day each month?

"Individual variation in cycle length, plus the varying lengths of calendar months, means that ovulation is not guaranteed to occur on the exact same numeric date every month," Chase White, MD, an OB-GYN at Einstein Medical Center Philadelphia, tells Romper. Even if your cycle is totally regular, the calendar isn't. Thus, why my birthday doesn't fall on a Friday every year, as I'd definitely prefer. According to White, most menstrual cycles — counting from day one of your first period to day one of the next — last between 25 and 35 days. The second half of your cycle, after you've ovulated, is known as the luteal phase, and it's very consistent. In fact, for a majority of women, the luteal phase lasts 14 days. The wild card here is the follicular phase, when the egg develops. That timeframe is a lot less consistent between women, according to White.

Ad failed to load

However, the fact that almost everyone shares a 14-day luteal phase is a real boon when it comes to figuring out when you ovulate each month — especially if your periods as a whole are fairly regular. To help you identify which day you'll ovulate, consider an example (details by White, names provided by me):

Anne and Mary Boleyn both start their period on the same day — Jan. 1. Anne Boleyn has 28-day cycles, while Mary has 32-day cycles. Both have very regular periods, and as a result, they can each predict when their next period will make a visit. Anne Boleyn predicts her period will arrive on Jan. 29, while Mary expects hers to come around again on Feb. 2.

While the overall length of their cycles differ, the post-ovulation phase lasts 14 days for both sisters. So Anne can count backwards 14 days from Jan. 29, to predict she'll ovulate on Jan. 15. Mary can count backwards 14 days from Feb. 2, and determine that she'll likely ovulate on Jan. 19.

Ad failed to load

Likewise, Anne expects her next period on Feb. 26, and ovulation on Feb. 12. Mary will expect her next period on March 6, and to ovulate on Feb. 20. Note that neither sister ovulates on the same date each month, despite the regularity of their cycles, because of the structure of the calendar (Anne expects to ovulate on the 15th in January, but on the 12th come February). If they so choose, the Boleyn sisters can keep playing this game, predicting periods and ovulation dates for months in advance.


But what if you're not as consistent as the two English courtiers in the example above? According to White, "'Normal' menstrual cycles should be fairly regular, with variation in length of less than about a week." Nevertheless, this is a human body we're talking about, so some variance is expected, and certain external factors — like stress, weight loss or gain, and medication — can shake up your cycle every now and again. Usually, you'll return to regular menstrual reality within one or two cycles. If you don't, White suggests visiting your OB-GYN to rule out an underlying health problem.

Ad failed to load

While you're definitely not supposed to ovulate on the same day each month — in part because calendar months don't all contain an identical number of days — you should ovulate pretty consistently, according to your body's internal rhythm. Discovering that rhythm can be tricky, but it's also well worth it. Using a period and ovulation tracking apps like Natural Cycles (as surely the Boleyn sisters did) for just a few months can help you understand your body better. If what you learn changes your life, or makes you feel more empowered, you can tweet about it on #yourcyclematters. Female fertility may be complex, but it's worth understanding, discussing, and sharing.

Check out Romper's new video series, Romper's Doula Diaries:

Ad failed to load

Check out the entire Romper's Doula Diaries series and other videos on Facebook and the Bustle app across Apple TV, Roku, and Amazon Fire TV.

Ad failed to load
Must Reads

Umm, Toys "R" Us Has A BOGO 50 Percent Off Deal So You Better Stock Up

After the holidays, you were probably hoping that your kid's massive toy collection would keep him entertained for a little while, at least. But that was wishful thinking, wasn't it? Because now that a couple of months have passed, all those must-hav…
By Jacqueline Burt Cote

Turns Out, Kim Kardashian's Favorite Mom Products Look A Lot Like Your Own Faves

Being a mom is really hard work, especially for the first few months, and Kim Kardashian West is no different in that regard. Now the mother of three, Kardashian says that there are a few products she just can't live without when it comes to raising …
By Abi Berwager Schreier

These 9 Instant Pot Recipes Will Make Even The Pickiest Eater Happy At The Table

Like any parent, I've had my share of parenting hits and misses, but one of my favorite "wins" is my daughter's diverse palate. I don't even know if I can take credit for it, but I would like to think I had something to do with her love for lentils, …
By Caroline Shannon-Karasik

Soda Might Hurt Your Fertility, Study Says, & Here's What You Can Do

Who doesn't love sugary drinks? I stopped drinking soda years ago, but I still love gulping down those fancy Starbucks coffee beverages. I don't have a big sweet tooth, but I am a sucker for sugar-sweetened beverages every now-and-then. Turns out, th…
By Annamarya Scaccia

10 Things No One Tells You About Having A Baby In Your 30s

If you're like me, you evaluate the pros and cons of any major life decision. When my husband and I were considering starting a family, I thought about my career, education, and financial stability. I wanted to know how a pregnancy and childbirth wou…
By Steph Montgomery

This Woman Thought She Had An Eyelash Stuck In Her Eye. Then It Moved.

I'm not a person who is easily icked out. As a kid, I collected bugs and thought I was going to be an entomologist and asked Santa Claus for ant farms and nets to catch bees. I'm still super curious about anything that flies and crawls, which might s…
By Karen Fratti

A Hot Mess Mom's Guide To Surviving Winter

As I sit here at my home office in Connecticut, it's cold. Damn cold. Winter is a rough season in New England and it's even worse when you're a parent and have to manage cooped up, restless children. It's even worse when you're a hot mess as it is, u…
By Jamie Kenney

5 Red Flags Your Toddler Isn't Eating Enough

Toddlers are notoriously picky eaters, at least in my experience. You offer mashed potatoes, they want french fries. You give them crackers, they scream for chips. It's frustrating, to be sure, but it's usually their way of vying for independence. It…
By Candace Ganger

11 Ways Your Pregnancy Will Be Different If You Have A Boy Vs A Girl

If you've been pregnant before, you might start comparing your previous pregnancies to that of your current pregnancy. A lot of things can change from pregnancy to pregnancy, based on a whole host of different factors (including how well you remember…
By Lauren Schumacker

35 Moms Share The Most Disgusting Things Their Husbands Do

I'm a human being who revels in challenges. I like when people present me with one, especially if they don't think I can meet or succeed it, and I like taking a challenge on, especially if it's unexpected. So when I aimed to uncover the most disgusti…
By Jamie Kenney

How Having Kids In Your 20s Affects You Later In Life

For parents, like myself, who had kids in their 20s, there are a number of questions that come to mind. When you're deciding what your future will look like, you'll likely consider what this means for your health, career, and more down the line. Thin…
By Tessa Shull

8 Reasons I Let My Toddler Play Outside Unsupervised

I'm not a helicopter mom, but I'm not exactly a free-range parent either. I like to think of myself as safely ensconced somewhere in the middle. I insist on certain safety measures, like car seats and helmets. I prefer to keep my 2-year-old in my sig…
By Kimmie Fink

12 Moms Share How They Stay Healthy During Flu Season

Unfortunately, we're in the middle of the roughest flu seasons in recent memory. And we’re not totally out of the woods, either. People around the country are still getting the flu, and, sadly, some of them are having to be hospitalized due to flu-re…
By Priscilla Blossom

8 "Mistakes" I'm Glad I Made During My First Pregnancy

As an adult, I've learned you never really stop hating being told what to do. When I was pregnant I was getting instructions at every turn, from doctors, relatives, and complete strangers on the subway. I would nod and smile but then go about making …
By Liza Wyles

Study: Drinking Two Glasses Of Wine A Day Is Good For Your Mind — Here's Why

There’s more scientific proof that a daily drink or two isn't necessarily a bad thing and could have a place in an overall healthy lifestyle. A new study out of the University of Rochester Medical Center (URMC) in New York found that — in mice, at le…
By Tiffany Thomas

Research Says Eating Carbs Can Lead To A Healthy Pregnancy, So Bring On The Pasta

In the world of me, no food is better than bread. I know it's supposed to be pretty terrible for you, high in calories, low in protein, and full of that modern-day demon, gluten... but guys, it's really yummy. Especially warm out of the oven, when th…
By Jen McGuire

These Photos Of Prince George Then & Now Will Give You Serious Baby Fever

The Duke and Duchess of Cambridge are expecting their third child in Spring 2018. With all of the excitement surrounding the new baby, it's easy to forget all of the good times that have already passed. The couple's eldest is already well into the sc…
By Azure Hall

This Is, Hands Down, The *Grossest* Thing Babies Do Inside The Womb

Your baby's life in the womb may be safe and warm, but it's also kind of grody. Seriously, the whole process of growing into a human being includes more than a few icky moments along the way. But this is the grossest thing babies do inside the womb b…
By Lindsay E. Mack