In a perfect world, we’d all have a standard 28-day cycle each month and a 100 percent accurate fertility phone. But since it’s 2020 and this isn’t the movies, your fertile window probably varies from month to month.

You had a period, then you had unprotected sex. Are you pregnant?

Possibly, but probably not. If you have a relatively predictable cycle (#blessed), here’s how your odds of baby making shake out:

  • If you have a super short cycle (<21 days), it’s possible — though rare — to get pregnant from having sex just after your flow. Sperm can live up to 5 days after sex, so they might swim around long enough to meet up with your next egg.
  • If you have irregular cycles, it’s possible — but still rare! — to get pregnant from period sex or sex just before or after your flow.
  • You’re most likely to get pregnant during your fertile window, the 6-ish days in the middle of a 21- to 35-day cycle.
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Getting pregnant just before or after your period is unlikely — but it’s not impossible.

Birth control is the only tried-and-true way to avoid getting preggo, even during your period. And if you’re trying for a bun in the oven, calculating your odds throughout the month is still helpful. The more you know, right?

Here’s how to tell your baby-making window from your safe-ish zone for unprotected sex.

When it comes to making babies, timing is everything. The same goes for unprotected sexcapades.

Most peeps with periods have a high chance of conceiving for just 6 days per cycle. It’s known as the fertile window.

The fertile window includes:

  • the 5 days before ovulation
  • the day of ovulation (the new egg’s 24-hour welcome party for nearby swimmers)
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Simple. Just calculate your window and enjoy worry-free romps for the rest of the month, right?

Not so fast. Like sex, your body’s schedule can be beautifully messy. It’s more art class than math class.

Even during your period, when pregnancy-friendly progesterone is low, your body is prepping for its next fertile window. Sometimes, your ovaries get eager and release an egg early. Or sometimes you skip an ovulation day.

There are several reasons ovulation might be disrupted:

  • age (hello, menopause!)
  • rapid weight gain or loss
  • lack of sleep
  • you’re stressed AF
  • thyroid probs
  • PCOS (polycystic ovary syndrome) or PID (pelvic inflammatory disease)
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Even if you don’t ovulate early or skip a month, you might have naturally short or long cycles. Most folks ovulate 2 weeks after their flow ends, but some people ovulate within a week after your flow.

The specifics of your fertile window matter because sperm stick around for days after ejaculation. Hence, squeezing in an unprotected sex sesh just before your fertile window could still result in pregnancy.

We’ve heard period sex hailed as the ultimate time for unprotected love making. Though baby making odds are slim, it’s not 100 percent risk-free.

During the 4 to 8 days of bleeding, you’re shedding the unfertilized egg from your previous cycle. This means there isn’t a new egg ready for baby making, but it doesn’t mean your partner’s sperm won’t hang out until the new egg makes its debut.


If you have sex toward the end of your period and you have a short cycle, it’s possible ye olde swimmers are still livin’ it up in your bits when you ovulate a few days later.

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You’re dealing with the same scenario here. It’s super rare to get pregnant a day or two after your flow, but you can’t discount lurking sperm.

If you have a naturally short cycle — 21 days or fewer — unprotected sex just after your flow is risky. If you have longer cycles, there’s still a chance you’ll ovulate sooner than usual.

Erm… NEVER?!

Just kidding (kinda). In general, your period is the part of your cycle when you’re least likely to make a baby. But regardless of timing, it’s impossible to be 100 percent sure that unprotected sex won’t result in pregnancy.

If you have a 28-day cycle that runs like clockwork, your fertile window lasts for about 6 days mid-cycle (days 14 through 20 in a perfect world). Your safest bet for unprotected sex is a week or so after ovulation — just before, during, or just after your period.

But — and we’re sounding like a broken record— you could still get pregnant if you have an unpredictable cycle, if you have short cycles, or if you have sex within 5 days of your fertile window (when the sperm are still kickin’).

If you’re trying to get pregnant, it’s vital to schedule plenty of time between the sheets during your fertile window.

If you’ve been getting frisky mid-cycle for a while and still aren’t preggo, it might benefit you to have sex more regularly. Cycles vary, after all. It also helps pinpoint your ovulation — knowledge is power!

Here’s how to get a better handle on your body’s ovulation patterns:

Fertility apps

Of course there’s an app for that. These handy ovulation trackers allow you to record everything from cervical mucus textures to when you last had sex. The key is to input as much info as possible as regularly as possible.

Even then, the app’s ovulation predictor is only a guesstimate. These apps are great for helping you get a baby on board, but they’re 👏not 👏a 👏substitute 👏for 👏birth 👏control!

At-home ovulation kits

Like pregnancy tests, ovulation predictor kits come in pee sticks, strips, and digital tests.

Your body produces sky-high levels of luteinizing hormone (LH) about 24 to 36 hours before ovulation. These tests detect LH surges to help you pinpoint the day or two before ovulation each month.

Progesterone test kits

Just before ovulation, your body releases a hormone called progesterone. If you’re someone with irregular periods, testing progesterone levels can be a helpful way to know where you are in your cycle.

Basal body temperature

Your basal body temperature (BBT) is your body’s resting temp. According to the Mayo Clinic, it tends to spike about half a degree (Fahrenheit) just after ovulation. Because the spike is so small, this isn’t a great method of birth control. But it helps determine your ovulation day if you’re trying to make a baby.

To track your BBT, you do need a hypersensitive BBT thermometer. Keep it by your bed so you can take your temp each morning before you move a muscle. Chart your temperature at the same time each day. When you notice a teensy rise for 2 to 3 days straight, you’ll know you’ve ovulated.

PSA on infertility

Ovulation is a critical part of baby making, but it’s not the only factor. Here’s when to consider calling a fertility specialist:

  • you’re older than 35 and have been trying for a baby for at least 4 months
  • you’re younger than 35 and have been trying for a baby for a year
  • you have a reproductive health issue such as PCOS, primary ovarian insufficiency (POI), uterine fibroids, or endometriosis
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Wondering if you’re preggo because you had unprotected sex during or just after your flow? The answer is maybe. It’s rare but not impossible to make a baby during your period. You could get pregnant at any point in the month, especially if you have short or irregular cycles.

If you’re trying to get pregnant, getting down right after your period probably isn’t the best timing. The odds are in your favor just before and during ovulation. Your best bet is to know thyself. Start tracking your cycles to identify your fertile window.

Think you might be preggo? Take a home pregnancy test or talk to your doc to find out for sure.