Implantation bleeding or period: how to tell from the timing, colour and flow, and when spotting needs a doctor

Implantation bleeding is usually lighter, shorter and browner than a period. Cleveland Clinic describes it as pink, brown or dark brown spotting that doesn't soak a pad, lasts a few hours to about two days and has no clots, while a period tends to start light, turn bright or dark red, get heavier and last several days. NUHS says implantation bleeding happens a few days after conception, when the embryo embeds in the womb lining, so it can arrive close to when your period is due and be easy to mistake for a light one. Not everyone gets it. A pregnancy test gives the answer: KKH's obstetricians say the most accurate time is the first day after a missed period. See a doctor for heavy bleeding, clots, or bleeding with strong cramps or one-sided pain.

Implantation bleeding vs period: side by side

The details for implantation bleeding come from Cleveland Clinic, the timing from NUHS, and the cramps and early signs from NUHS's guide to early pregnancy. If you track your cycle, our ovulation calculator shows your likely fertile window and when your next period is due, which helps you place the bleeding.

How to tell for sure: take a test

Spotting alone can't tell you whether you're pregnant. A home pregnancy test can, if you time it well. KKH's obstetricians, writing on SingHealth's HealthXchange site, say you can test as early as six days after ovulation, but the first day after a missed period gives the most accurate result. Cleveland Clinic suggests waiting until the spotting has stopped and your period is clearly late. If you test early and it's negative, test again a few days later.

Our guides to when to take a pregnancy test and faint lines on a test go into timing and reading results.

Other early signs that point to pregnancy

Spotting means more alongside other signs. NUHS lists the ones that often show up in the first weeks:

If you have one or more of these, NUHS suggests seeing an obstetrician. Our guide to the early signs of pregnancy explains each one, and once a test is positive, our due date calculator works out your due date from the first day of your last period.

When spotting needs a doctor

Light bleeding in early pregnancy is common and often harmless, KKH says, but it can also be a sign of miscarriage or an ectopic pregnancy, so get advice if you're unsure. SingHealth lists implantation bleeding as one cause of bleeding in early pregnancy, alongside a collection of blood around the pregnancy sac, low progesterone and infections.

See a doctor the same day if you have:

• Bleeding as heavy as a period, or heavier, or with clots
• Strong cramps, or pain on one side of your lower tummy
• Pain in your shoulder tip, dizziness or fainting
• Bleeding with a fever or a smelly discharge
• Bleeding after a positive pregnancy test

Our guide to bleeding in early pregnancy covers what happens at these units and what a threatened miscarriage means.

Frequently asked questions

What colour is implantation bleeding?

Usually pink, brown or dark brown, says Cleveland Clinic. Bright or dark red blood, a heavy flow or clots point more to a period.

How long does implantation bleeding last?

From a few hours to about two days. Bleeding that goes on longer and gets heavier is more likely to be a period.

Can I take a pregnancy test during implantation bleeding?

You can, but it may be too early to show. KKH's obstetricians say the most accurate time to test is the first day after a missed period.

Is implantation bleeding a sign of a healthy pregnancy?

It's a normal part of early pregnancy for some women, and many have none at all. Its absence means nothing, and light spotting with no pain is usually harmless.

When should I worry about spotting in early pregnancy?

See a doctor if it's heavy, has clots, comes with strong cramps or one-sided pain, or makes you dizzy. KKH says bleeding can sometimes signal a miscarriage or ectopic pregnancy.