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Implantation Bleeding: Causes and Symptoms

Medically Reviewed by Caitlin Goodwin, MSN, RN, CNM
Here's how long implantation bleeding usually lasts, how it looks, and other symptoms of implantation bleeding.

Are you trying to get pregnant and have noticed a change in your bleeding? Are you unsure if it’s an early sign of pregnancy or your period starting? Telling the difference between period and implantation blood just takes a bit of expertise!

Every hopeful mom is eager to see the first sign of a new life growing, so it’s hard not to panic when your body behaves unexpectedly. If you’re feeling stressed out about a spot of blood when you suspect you’re pregnant, learning a bit more about implantation bleeding may put your mind to rest.

Is Implantation Blood Normal During Pregnancy?

As women, we have a pretty familiar relationship with blood, especially if comes from down there. It’s just part of life, and after a while, it stops being gross and scary and just becomes routine.

But there are lots of reasons why we may see of blood besides a period. From irritation to breastfeeding to hormonal changes, our bodies can expel blood for a variety of reasons. One of these is implantation bleeding during early pregnancy, and it’s perfectly normal!

What is Implantation Bleeding?

Light spotting during early pregnancy is usually the sign of the fertilized egg lodging itself into the uterus lining. As the egg moves down your fallopian tubes and into your womb, it nestles into the uterine lining, nice and snug. But this can cause enough irritation to produce light, harmless bleeding.

When Does Implantation Bleeding Occur?

Contrary to popular belief, this form of bleeding doesn’t happen right when the actual implantation does. Instead, it’s a bit of an “aftermath,” a sign it has happened instead of is happening.

You shouldn’t expect to see implantation bleeding until the deed is done. Bleeding won’t happen until at least five days after conception, but it can take up to 10 to notice any bleeding if it happens at all (1). In some cases, this coincides with the typical time of a woman’s period and she may not realize she is pregnant at all.

Does Every Woman Experience Implantation Bleeding?

Only around 30 percent of pregnant women experience implantation bleeding.

If you don’t see any sort of spotting in your early pregnancy, don’t freak out — you’re in the majority if you haven’t noticed it. And even if you did bleed a tiny amount, you could’ve missed it.

Relying on one clue to prove your pregnancy is never a good idea, so if you think you may be pregnant but haven’t noticed spotting, just look for other signs your body gives. Some women may also experience spotting with only one pregnancy if they’ve had multiple children. Each journey is different!

What Does Implantation Bleeding Look Like?

A lot of women get confused when they try to figure out if what they’re seeing is a sign of pregnancy or just the beginning of their period. They may also start to wonder if something is wrong, especially if a pregnancy wasn’t planned or expected.

Telling period bleeding from implantation bleeding is pretty simple if you have a good relationship with your cycle and know what to look for. Picture what a typical period looks like for you, and compare it to what you’re seeing now.

Some of the things you’ll notice with implantation bleeding:

  • Amount: Implantation bleeding is nowhere near as heavy as a period. It shouldn’t be enough to fill up a pad, so if it’s less than what you’d see during a period, this is a great clue.
  • Color: Every woman sees a different pattern with her cycle, but you should be familiar with what shade your blood usually is during your period. Implantation bleeding is almost always a different color than period blood, sometimes dark brown, other times almost pinkish.
  • Thickness: Even women who experience a light flow usually can tell the difference between implantation bleeding and period blood. Unlike what you see once a month, this type of bleeding is thinner and won’t come out in thick clumps, but streaks or slight drops.
  • Duration: The length of implantation bleeding differs between women, but the maximum amount is about three days of spotting. This is much shorter than a period, so if you see blood for a short time and it disappears, this is a good sign you’re pregnant and experiencing implantation bleeding.
  • Timing: Implantation bleeding generally comes before you expect to get your period by a couple of days. If you experience light bleeding and it comes before your expected period, this is a good sign that it is implantation and not your period.

Even if you feel like what you’re seeing fits all four of these categories, don’t stress yet. You should never accept anything as definite until a doctor tests you, but it doesn’t hurt to keep paying attention to your body!

How Common is Heavy Implantation Bleeding?

Implantation bleeding is not all that common, and heavy implantation bleeding even less so. There’s little information out there about heavy or late bleeding that isn’t a period or a miscarriage. While there are a few success stories buried in various mommy forums and comment sections, it’s important to note that heavy bleeding is usually not a good sign.

The main reason heavy implantation bleeding occurs is because of something wrong with the initial implantation itself. If this happens, it may be because the egg has planted itself somewhere it shouldn’t, such as the cervix, fallopian tube, or abdomen.

This condition is called an ectopic pregnancy, meaning the egg is trying to grow somewhere it can’t (2). Unfortunately, these pregnancies almost always end in termination and may be life-threatening to you, so seek help immediately if you experience heavy implantation bleeding and you’re sure it isn’t your period.

How Common is Late Implantation Bleeding?

Implantation occurs after fertilization. It takes the fertilized egg some time to move from the fallopian tubes and down into the uterus, so there’s usually around 6 to 14 days from conception to the fertilized egg being fully implanted into the uterus.

You could see implantation bleeding anywhere from the fifth or sixth day after conception, but it can occur so late it coincides with your period due date.

Late implantation bleeding can be an alarming sight, and disappointing if you’re trying to conceive. But it doesn’t always indicate a miscarriage or the absence of a pregnancy! Some women have positive pregnancy tests after what they thought was their “period” because what they actually experienced was late implantation bleeding.

In some cases, implantation just happens later. Studies have shown, however, that the later the implantation, the more likely a miscarriage will occur (3). This is not written in stone, but if you’re worried, talk to your doctor.

Does Heavy Implantation Bleeding Mean Twins?

Once again, there isn’t a lot of reliable information out there about the connection between twins and heavy implantation bleeding. When you’re pregnant with twins, most signs of pregnancy are exaggerated, and some women have reported seeing more spotting for longer periods in their twin pregnancies.

But truthfully, these occurrences are rare on their own, and even more unlikely to happen all at once. On one hand, the body is put under more stress with twins, so you may be more likely to see implantation bleeding. On the other, many women experience implantation bleeding and go on to have singleton pregnancies.

Implantation bleeding is caused by damage to tiny blood vessels in the uterine lining, so it stands to reason if there are two eggs (like in a fraternal twin pregnancy), there would be twice as much bleeding! However, this explanation makes less sense for identical twins, and anecdotal evidence aside, there’s not much to say that implantation bleeding alone is a sign of twins.

Keep Your Doctor In The Loop

As always, if you notice anything unusual, contact your doctor first. Especially whenever it concerns spotting or heavy bleeding, since these could be early warning signs for something serious.

Is Implantation Bleeding a Miscarriage Sign?

It’s easy to tend to cling to an unusual sign or symptom as proof something negative is happening, especially if you’ve had bad experiences in the past with fertility. It’s also hard to see an unexplained change and stay positive, especially if your hopes are high.

But more often than not, light implantation bleeding is not a cause for concern. In fact, you can take it as a reassuring pat on the back!

Though miscarriages begin with spotting that may seem like implantation bleeding, they quickly become crampy, clotty, heavier and thicker. You won’t see the thin blood for long if it’s indeed a miscarriage, so your worries should be put to bed after 24 hours of noticing slight spotting.

Can Implantation Bleeding Include Clots?

Unlike period blood, implantation bleeding is very light and thin and doesn’t last long. Blood clots happen when a lot of blood pools up in the bottom of the uterus and can’t be expelled through typical contractions (aka our lovely friend cramps). There will never be enough blood to pool and thicken if you’re experiencing implantation bleeding, so this should never occur.

If you do see clots in blood that otherwise fits the bill for implantation bleeding, let your doctor know. Clots can be a sign of miscarriage, especially if your bleeding is light like it would be during implantation (4).

Other Symptoms of Implantation Bleeding

Both early pregnancy and the start of your period can manifest similar symptoms, which is frustrating for an eager mom waiting to take a pregnancy test.

You know your body, so you’ll know what’s normal and what isn’t, but there are a few key symptoms that make themselves present during implantation bleeding.

  • Light cramping: As the egg arrives into its soft, cushiony new home, your endometrium is getting ready to be a gracious host for the next 9 months. All of this can result in some cramping.
  • Lower back pain: Just like cramping, this is a sign your body’s hormones are working hard to create the perfect place to grow your baby.
  • Headaches: As progesterone courses through your body and your womb kicks into action, the sudden change may cause you to experience headaches. This is normal.
  • Mood swings: Your body is preparing to change drastically over the next few months and your hormones have kicked into high gear. This can cause some mood swings, similar to PMS.

You may notice these symptoms are suspiciously similar to those of your period. To avoid disappointment, it’s important not to rely on these symptoms alone; waiting until the moment you can take a pregnancy test is, unfortunately, the only way to know for sure.

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Are Tampons Okay During Implantation Bleeding?

If there is any chance you’re pregnant, you should never use a tampon. It’s something I’ve talked about before, but it’s good to mention again.

Implantation bleeding shouldn’t be enough to warrant the use of a tampon anyway. You’ll be able to deal with it with little more than a thin panty liner. Typical implantation bleeding won’t be enough to even fill this, so if it does, you’re probably not pregnant and you’re starting your period.

Tampons can introduce bacteria into the vagina that can harm you and your baby in some cases. If you’re actively trying to become pregnant, always wait to use a tampon until you’re sure there is no chance of pregnancy.

Headshot of Caitlin Goodwin, MSN, RN, CNM

Medically Reviewed by

Caitlin Goodwin, MSN, RN, CNM

Caitlin Goodwin MSN, RN, CNM is a Certified Nurse-Midwife, clinical instructor and educator. She has ten years of nursing experience and enjoys blogging about family travel and autism in her free time.