Implantation bleeding explained

Implantation bleeding is usually lighter, shorter and a slightly different colour to your normal period.

implantation bleeding symptoms and causes
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If you experience light bleeding or spotting in the lead up to your period, menstruation might not be to blame - particularly if you're trying for a baby. Instead, the culprit could be implantation bleeding, which can be an early sign of pregnancy as some women experience light bleeding just after they've conceived.

But what exactly is implantation bleeding, and how can you tell the difference between this and your period? Dr Lara Batchat explains what implantation bleeding means, why it happens and the telltale signs that you might be pregnant:

What is implantation bleeding?

Implantation bleeding happens when a newly fertilised egg attaches itself into the lining of the womb, known as the endometrium. This can result in very light vaginal bleeding, commonly described as spotting. It is completely harmless and happens in about a quarter of pregnancies, in fact, in some cases it may be the first sign of pregnancy.

When does implantation bleeding happen?

In order to conceive a pregnancy, a sequence of events must occur. First, an egg (released by the ovary around day 14 of the menstrual cycle) needs to be fertilised by a sperm. This happens in the part of the female reproductive system called the fallopian tube. From there, the fertilised egg develops into an embryo and travels down into the womb, where it will settle and grow until birth.

If implantation bleeding occurs, it can often be seen at roughly the same time as the next period would be expected.

The stage when the embryo implants into the womb lining is known as implantation and during this event, tiny blood vessels there can be disturbed and so bleed. Implantation normally happens between one to two weeks after fertilisation. If implantation bleeding occurs, it can often be seen at roughly the same time as the next period would be expected, which can be misleading.

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Implantation bleeding symptoms

The blood vessels that bleed during implantation are only small and heal quickly, so the resulting symptoms reflect this.

Implantation bleeding is:

  • Usually short lived, lasting only one to two days
  • Light – resulting in only a few spotting stains rather than heavy bleeding
  • Commonly pink or brown in colour
  • Sometimes associated with mild period-like cramps

    You may also notice symptoms of early pregnancy too, such as:

      How can I distinguish between implantation bleeding and my period?

      The timing of implantation bleeding can create confusion because it often coincides with the date your period may be due. Of course, the best way to work out if the bleeding is pregnancy related is to do a pregnancy test. If this is positive, you can feel confident that the bleeding is not representative of a period. However, sometimes a pregnancy test may not yet show up a positive result, and so in the case of a negative result, it may be worthwhile waiting a few more days before repeating the test again.

      Implantation bleeding is usually lighter, shorter and a slightly different colour to your normal period.

      Another approach is to consider the timings of your cycle and when you last had sex. If this was more than two weeks before the bleeding starts, the cause is unlikely to be implantation bleeding.

      Implantation bleeding can look and feel quite different to your normal period – it's usually lighter, shorter and a slightly different colour, as we mentioned earlier.

      Remember though, that it can be really tricky differentiating the two and many of us have been caught out thinking implantation bleeding is a period, only to then discover this was not the case. Often, it’s a question of ‘time will tell’.

      When to seek medical attention

      It’s not unusual to have light bleeding during pregnancy and more often than not, this is harmless, without any detrimental effect on the baby or mother. However, vaginal bleeding can be a sign of miscarriage, as well as potentially life threatening conditions such as ectopic and molar pregnancies. For this reason, it’s important to seek urgent medical attention for any vaginal bleeding in the context of a positive pregnancy test. Your doctor will be able to run some simple examinations and tests to rule out anything serious.

      Last updated: 17-05-2021

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