Implantation bleeding: what it looks like and when it happens

Some people have light bleeding or spotting in very early pregnancy, around the time their period is due. It’s often called implantation bleeding, because it happens around when the fertilised egg attaches to the lining of the womb. Not everyone has it, and it can be easy to mistake for the start of a period.

When does it happen?

Implantation happens about 6 to 12 days after ovulation, (around days 20 to 26 of a 28-day cycle), and spotting in early pregnancy tends to come around the time your period would be due.

Is it really caused by implantation?

It isn’t certain. One study that timed implantation found bleeding rarely happened on the day of implantation, and about 1 in 10 women had some bleeding in their first 8 weeks of pregnancy. The name has stuck, but whatever the cause, light spotting in early pregnancy is common.

What does it look like?

The NHS describes it as a bleed similar to a very light period, with some spotting or only a little blood. You may only notice it when you wipe or on a panty liner. People describe different colours, and there’s no colour that proves it’s one thing or another.

Implantation bleeding or a period?

It can be hard to tell. Spotting in early pregnancy is usually much lighter than a period: a few spots or a little blood, rather than a flow that needs a pad or tampon. A period usually builds into a proper flow over a day or so.

A pregnancy test will tell you whether you’re pregnant, but not what caused the bleeding. If your period hasn’t come properly, test from the day it was due. If it’s negative and your period still doesn’t arrive, test again a few days later. If it’s positive, get the bleeding checked.

Other causes of spotting in early pregnancy

Changes in your cervix. It has a bigger blood supply in pregnancy, so it can bleed a little after sex or an examination.
Infections, including some sexually transmitted infections.
A pregnancy that isn’t continuing, including a very early loss.
Ectopic pregnancy, when a pregnancy grows outside the womb. It can cause pain low down on one side, but not always.

Most light spotting in early pregnancy turns out to be nothing serious, but it’s always worth getting checked, especially if it comes with pain.

What to do if you have spotting

If you don’t know whether you’re pregnant, take a test from the day your period was due.
If you’re pregnant or might be, contact your maternity unit, an early pregnancy unit or NHS 111 for advice.
Use pads or panty liners rather than tampons, so you can see how much you’re bleeding.
Make a note of when it started, how much there is and whether you have any pain. It helps whoever you speak to.

Questions people ask

How long does implantation bleeding last?

There’s no reliable research on this. Most people describe spotting that’s brief and light. Bleeding that becomes a flow, or goes on for several days, is more likely to be a period, or something that needs checking.

Can you have implantation bleeding and a negative test?

Yes, if you test before there’s enough hCG to detect. Test again from the day your period was due, or a few days later.

Can implantation bleeding be heavy?

Light spotting is what people usually describe. Heavy bleeding in early pregnancy isn’t implantation bleeding: call 999 if you’re soaking a pad soon after putting it on.

Does implantation bleeding mean the pregnancy is healthy?

Spotting doesn’t tell you either way. Many people with spotting go on to have healthy pregnancies, and many healthy pregnancies have no spotting at all.

When to get help

Mild cramps that ease with rest are usually nothing to worry about. But if you’re pregnant, or think you could be, get urgent advice from your maternity unit, an early pregnancy unit or NHS 111 if you have:

any bleeding or spotting, even if it’s light
tummy pain that’s severe, on one side, or hasn’t eased after resting for 30 to 60 minutes
pain in the tip of your shoulder

Call 999 if you have bleeding along with severe tummy pain, pain in your shoulder, or feeling sick, faint or dizzy, or if the bleeding is heavy (soaking a pad soon after putting it on). Also call 999 if you have sudden, sharp and intense tummy pain and you feel very dizzy or faint, feel sick or look very pale. These can be signs of an ectopic pregnancy or a miscarriage that need treating straight away.