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Your Period, on Birth Control: What's Normal? 9 FAQs

Your Period, on Birth Control: What's Normal? 9 FAQs

  • Sonia Easaw, M.S., MPH
    Reviewed By: Julie Lamonoff, CNM, OBGYN-NP, Shannon DeVita DNP, FNP-BC, CPNP-PC
    Updated:

If you're worried that your period is out of whack, even though you're on birth control, for heaven's sake, you've come to the right place. The truth is that periods on birth control are anything but "normal." You're pretty much guaranteed to have changes to your menstrual periods when you're on birth control, though they settle down over time.

The manipulation of the normal menstrual cycle is why you can use birth control to delay or skip your period. But we digress.

Here are 9 of the top questions we get on this topic. Watch out: some answers may blow your mind!

*Editor's note: If you have irregular bleeding or spotting but you're NOT on birth control, then you should ask your doctor about it.

Number 1: Is it normal to bleed at all while on birth control pills?

The answer is yes; scientists designed the pill so you'd bleed during the placebo week. This was the one feature of combined oral contraceptives (birth control pills) that scientists let remain unchanged over the decades.

That said, you will probably have unpredictable bleeding patterns during the first few months of taking any birth control method. The National Institutes of Health says that irregular bleeding can happen when you take hormonal birth control like birth control pills or IUDs.

Here are 3 ways to describe how unpredictable periods can be on birth control pills:

  • You may have your period on birth control during active pills (the time when, technically, you shouldn't be bleeding).

  • You may have spotting, also called breakthrough bleeding, during the first few months. Doctors say this is the most common symptom when taking any brand.

  • You may have a missed period on birth control. But that doesn't automatically mean your pregnant.

This unpredictability is usually not forever. As your body adjusts to birth control pills, you'll probably just have bleeding during the regularly scheduled programming (oops, during the placebo week) when you take those "sugar pills" that have no hormones in them. But if you're unsure, it's always a good idea to check with your health care provider about it.

But get this. It's not medically necessary for you to have this scheduled week of bleeding. We'll explain more later.

Number 2: Can you get your period on birth control during the active pill weeks?

Yup. Most certainly, you can get your period, or what may seem like your period, when you're not supposed to get it. Unscheduled bleeding that just shows up is one of the main reasons women stop using a birth control method. But before you decide to give up, know that unpredictable bleeding or spotting usually gets better in a few months, depending on the method. Talk to your doctor about what can help and how to address the problem if it gets too bothersome.

Number 3: Is your period on birth control a "real" period?

News flash: Your period on birth control is not "real." Why do you have to bring out the box of pantiliners or pads at a random time, you may ask? It's all the pill's fault, actually, but no worries - your body will adjust and become friends soon. Here's the science behind how this all happens:

What's a menstrual period, anyway?

Your period during a natural menstrual cycle (sans the pill) happens because your uterus is shedding its inner lining.

The body's natural process is to have your uterine lining become thicker in anticipation of fertilizing the egg (think grandparents who are hoping for grandkids). When it finds out no fertilization is happening, it sheds that lining.

No baby is coming to protect and nurture in there, after all! The unfertilized egg, along with blood and tissue, passes through the vagina and inevitably shows up on your tampons and pads. This whole process is controlled by the rise and fall of your body's hormone levels, specifically estrogen and progesterone

How the pill "interrupts" things

Now when you're on the pill, things are very different.

The pill delivers synthetic hormones estrogen and progestin to your body. It tells your system don't even bother releasing an egg this month (a process called ovulation). Ovulation is when a mature egg, good and ready to match with a suitable sperm, is released from the ovaries.

By preventing ovulation, the pill helps to prevent pregnancy before you end up with a fertilized egg. It also does some other things to make the possibility of pregnancy even more unlikely, like thickening your cervical mucus, making it harder for those pesky sperm to get into your uterus.

So then, what's the true identity of a "period" on birth control?

Get ready for this:

Your period on birth control is kind of fake. It's called a "withdrawal period," not because your body is shedding the uterine lining but because your body is going through hormone withdrawal. Essentially, the lab-derived hormones that the pill delivers are there to call the shots, and when you take the placebo pills, the active hormones start to exit the premises. The change in hormone levels triggers your body to build up or shed that lining, which results in bleeding or spotting.

Your period on birth control is a withdrawal period meant to mimic your natural one. It is not biologically necessary.

So there you have it. That's why your period on birth control looks and acts so different.

Number 4: Can you miss your period on birth control?

For sure, you can miss your period on birth control. Global health experts say that different types of menstrual changes, including the absence of a period, are expected when you're on birth control. It is common to miss your period while using a hormonal birth control method.

Doctors say that when you use hormonal contraception unless you have concerning symptoms, you should not assume that the absence of bleeding by itself is a sign of pregnancy. But if you're worried, you should ask your doctor about it.

Number 5: When do you get your period on birth control?

So the pill was designed so you'd get your period during the time you take the placebo or "sugar" pills, also called inactive pills. This commonly happens for a week at the end of a standard pill pack.

Though you may be supposed to get a period during the placebo week, it doesn't always happen. You can be late or early, or never see it come at all. The UK National Health Service says that irregular bleeding, like bleeding between periods, is common when you're first starting to take birth control.

That said, there are carefully designed times you're supposed to get your period while on birth control. Note this varies depending on the type of birth control that you take. The combined oral contraceptive pill (birth control pills that deliver a combination of the hormones progesterone and estrogen) are the most common.

Standard schedules for different types of birth control pills and methods

Here is when you're supposed to get your period, based on method:

Combination birth control pills:

There are various regimens of combination birth control pills, each with its own schedule. The regimen where you have 21 days of active pills and then 7 days of inactive pills is most common. Here they are:

  • Traditional 7-day schedule (most-common): You would have your period during the 4th week of the month, for 7 days.

  • Traditional 4-day schedule: You would have 24 active pills and then have your period during the last 4 days of the pack.

  • Continuous or extended-cycle: You would take active pills for longer than 28 days.

Most have 84 days of active hormones followed by 7 days of placebo, or 7 days of a low-dose hormone. You'd theoretically have a period during the final week of a 3-month period on such a schedule.

Birth control patch:

The birth control patch is designed to be applied once a week for 3 weeks and then removed for 7 days. It's in that fourth week that you'd expect a menstrual period. You'd then continue the pattern of 3 weeks on the patch, 1 week off.

Birth control vaginal ring

The vaginal ring, like Annovera™, was also designed to be in place for 3 weeks and then removed for 1 week. It's during the week without the ring when you'd expect to get your period. The following month, you'd go back to the same schedule of 3 weeks with the ring and 1 week without. Again, the makers of the ring designed it so you could have a menstrual bleed.

Birth control arm implant or IUD

With a long-acting birth control option like the arm implant (like Nexplanon™) or an intrauterine device (IUD like Mirena™), your menstrual bleeding will change. There is no scheduled withdrawal bleeding, however.

With an arm implant, your menstrual bleeding may be longer or shorter, or you may not even have a period. With an IUD, most women have reduced menstrual bleeding and may not get their period at all after some time.

Can you get pregnant on birth control

Your periods change when on birth control. Usually, this is normal, and you may not even get your period on birth control. If you're worried or have other symptoms of pregnancy, you should ask your doctor.

Theoretically, every contraceptive method has a failure rate. If you take your combined birth control pill consistently and correctly, which is called perfect use, your chances of getting pregnant in the first year are 0.3%. With typical use, meaning you may miss multiple pills here and there, your chances of getting pregnant go up to 9%.

Here are what the Mayo Clinic says are the most common signs of early pregnancy:

  • Missed period

  • Tender, swollen breasts

  • Nausea

  • More frequent urination

  • Fatigue

There are other, less obvious signs of pregnancy:

  • Moodiness

  • Bloating

  • Light spotting

  • Cramping

  • Food aversions

  • Nasal congestion

Practically, however, doctors say that it is common to not get a period when on birth control and shouldn't be cause for concern if there are no other symptoms.

Number 6: How long should you have your period on birth control?

When you have a period on birth control, it can be unpredictable. Strictly speaking, you should get your period during the time you're taking placebo pills. But unscheduled bleeding, whether light spotting or heavy, happens when you're on birth control. Usually, the bothersome unpredictable bleeding will resolve itself after a few months.

But what if you have bleeding for a long time outside of the placebo window? In general, periods should last between 4 and 8 days.

Let's start with defining and quantifying what we mean when we refer to bleeding or spotting. That'll help you determine it for yourself, and it'll help you if you decide to talk to your doctor about it.

Definitions: So how do you define "bleeding"

It's nice that researchers like to define things. Here's what they mean by spotting, bleeding, bleeding that's too long, etc.

Bleeding: When we refer to menstrual "bleeding," it means blood loss that requires you to wear sanitary protection like a tampon, pad, or pantiliner. The period blood might look red in color, as it's probably fresh blood.

Spotting: When we say "spotting," it means that the blood loss is so small that you wouldn't have to wear any type of sanitary protection - not even pantyliners. The spotting could look like a brown discharge, the kind that appears towards the end of your period when the blood is "older" since it's been there longer.

An episode of bleeding/spotting: You may have irregular spotting or bleeding during the month on birth control. Here's how you can define an "episode" of the spotting or bleeding: The episode is preceded by 2 regular days without any spotting/bleeding and followed up by 2 days straight without any spotting/bleeding.

Infrequent bleeding: Fewer than 3 bleeding or spotting episodes in 3 months

Prolonged bleeding: Here's something to note. If you're thinking your period on birth control is going on too long, "prolonged" bleeding is defined as any bleeding/spotting episode lasting more than 2 weeks in 3 months.

Frequent bleeding: More than 5 bleeding or spotting episodes in 5 months.

Amenorrhea: This the medical term for when you don't have your period in 3 months.

Is your period on birth control, either bleeding or spotting, lasting too long? The Mayo Clinic has some good advice:

  • You should continue taking the pill as directed to prevent unplanned pregnancy.

  • You can track the breakthrough bleeding in a calendar.

  • If the breakthrough bleeding lasts more than 7 days in a row, or over a period of 3 months or more, ask your doctor about it.

Number 7: What's "normal" for a period on birth control?

The UK National Health Service says that irregular bleeding, like bleeding between periods, is common when you first start to take hormonal contraception like birth control pills, the patch, or the shot (Depo-Provera™.

Here are some facts about bleeding irregularities when you take birth control pills:

  • Overall, birth control pills should decrease how much you bleed.

  • Irregular bleeding is a common side effect during the first 3 to 6 months of taking the pill. It's so common that 30-50% of women experience it.

  • The good news is that irregular bleeding will lessen or go away with time, usually after 3 months, when only 10-30% of women experience unscheduled bleeding.

It may be helpful to describe what bothersome bleeding can look like when you're on birth control:

  • Spotting (minimal blood loss that doesn't require sanitary protection)

  • Unscheduled bleeding (also called breakthrough bleeding) when you're bleeding between periods or while taking active pills

  • Missing periods on birth control (the medical term is amenorrhea)

  • Short periods

Number 8: What's an "abnormal" period on birth control?

When the National Institutes of Health talks about vaginal bleeding, they say that women who take birth control pills may experience abnormal vaginal bleeding or breakthrough bleeding. So are they saying that "abnormal" bleeding is "normal" when you're on the pill? Well, to a degree. They follow by saying that breakthrough bleeding should go away on its own, but you should talk to your doctor if you have concerns.

Here are some symptoms of abnormal vaginal bleeding to watch for:

  • Bleeding or spotting between periods (though this is common when taking birth control pills)

  • Bleeding after sex

  • Heavy periods, which could mean passing large clots, needing to change your pad/tampon in the night, soaking through your pad/tampon every hour for 2 to 3 hours in a row

  • Bleeding for more days than usual or more than 7 days

It's a good idea to keep a record of these symptoms if you have them. You should note the dates when these symptoms start and end and how many pads/tampons you're soaking through if the bleeding is heavy. Jotting down these notes will be a godsend when you seek medical advice.

Number 9: Do you even need a menstrual period at all?

Here's a fun fact: Monthly menstruation isn't really necessary. In hunter-gatherer times, women were having babies one after the other, and they breastfed for long intervals, which suppresses ovulation and menstruation. Prehistoric women had about 50 menstruations, while modern women have about 450 periods!

With a 28-day cycle (21 days of active pills, 7 days of placebo pills to allow for a withdrawal period), the traditional birth control pill has no basis in biology. The makers of the pill decided to go this route to mimic the natural menstruation cycle to be more acceptable to society.

We know what you're thinking: Can I just take birth control pills and not have my period at all? The answer is yes; you're allowed to skip your periods using birth control pills. You should ask your doctor if you're interested. We got all the information in our previous article on how to delay your period.

Recap: Your period, on birth control

We get it: We've been taught that getting your period is a natural sign of femininity and means that everything is working normally for having babies. But the truth is that having your period on birth control is not the same thing as natural menstruation. Instead, it's a different beast altogether.

*Editor's Note: If you're having irregular periods or spotting and you're NOT taking birth control, then you should follow up with your doctor.

You should know that:

  1. Changes to your periods are typical when you're taking birth control pills. Make sure you're taking your pills as directed.

  2. Unless you have other concerning symptoms, not having your period while taking the placebo birth control pills does not automatically mean you're pregnant. However, you can check with your doctor if you're unsure.

  3. Once you stop using birth control, then your periods should go back to normal, and your chances of getting pregnant will return to normal.

As always, if you have bothersome irregular bleeding, don't hesitate to ask your doctor. There may be a way to change your method, or they can let you know if it's something that will go away anytime soon. It's super helpful to track what's going so you can present that to your doctor. Believe us, they like data, so record the dates it's happening and what it looks/feels like. You've got this!

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