Implantation bleeding in pregnancy

woman with doctor

Trying to tell if you’re pregnant can be tricky at the best of times, and implantation bleeding doesn’t help. The symptoms are often similar to your period, so it's sometimes difficult to spot the difference. Implantation bleeding is not something to worry about, and it doesn't require medical treatment, but it's good to rule out any other causes of bleeding in early pregnancy.

When does implantation bleeding occur?

Implantation bleeding occurs at the begnning of pregnancy, when a fertilised egg embeds itself in the lining of the uterus, so it can start growing. It’s a completely normal part of early pregnancy, but can be a bit alarming if you’re not expecting it, or disheartening if you’re trying to get pregnant and mistake it for your period.

Implantation bleeding is fairly common – about 20-30% of women will experience it during early pregnancy. You’re more likely to bleed if it’s your first pregnancy, as with subsequent pregnancies your uterus is more used to it.

How long does implantation bleeding last?

As bleeding only happens while the egg is attaching itself to the uterine wall, it won’t last long – maybe only a couple of hours, or at most 1-2 days. The flow will be light and possibly inconsistent, and there are normally no clots.

What does implantation bleeding look like?

My implantation bleeding was like the beginning of my period but didn't get any heavier. It lasted for three days or so. I went to the GP because I was worried, had a smear test, my boobs got bigger and I tested on day 30 – I was pregnant!

The symptoms are quite similar to ones you might get just before your period, such as:

  • A pink or brown discharge or spotting
  • Light or faint cramping
  • Mood swings
  • Headaches

As it happens right at the beginning of pregnancy, often at a similar time in your cycle to menstruation, it’s often confused with having an early period.

How can I tell if it’s implantation bleeding or my period?

Although there’s no way to be certain until you either get your period or a positive pregnancy test, there are a few differences between implantation bleeding and normal menstruation.

  • Colour – Implantation bleeding is usually pink or dark brown, whereas period blood tends to be bright red. This is because it takes time for the blood to move out of your uterus and into the vaginal cavity. Of course you know your body better than anyone – and if you’ve been trying to conceive for a while, you’ll probably be an expert on your periods.
  • Duration – Implantation bleeding doesn’t usually last for more than one or two days, and is light in flow. If the bleeding lasts longer than this, or the flow starts to get heavier, it’s very likely to be your period.
  • Timing – Implantation bleeding generally occurs about 10 days after ovulation, whereas menstruation occurs after 14. As such, spotting on day 22-25 of your cycle is theoretically more likely to be implantation bleeding than the beginning of menstruation. This isn’t a hard and fast rule though – sometimes your period can just turn up early, so it’s a good idea to keep track of your cycle.
  • Cramping – You might experience light cramps as a symptom of implantation bleeding, but these aren’t the same as period cramps. Menstruation cramps are usually more painful, and can get stronger over the course of your period.

Should I worry about implantation bleeding?

Generally speaking, implantation bleeding is harmless and it doesn’t need any medical treatment, but if you speak to your doctor they will be able to provide some much-needed reassurance.

If you find yourself experiencing other symptoms such as nausea, dizziness, abdominal pain or vomiting, or if you experience extended bleeding, it’s worth contacting your doctor straight away. There can be a variety of reasons for bleeding during early pregnancy, and these symptoms can be early indications of something more serious, so it's worth getting checked out.

Should I take a pregnancy test?

Current advice is to wait three days after experiencing implantation bleeding before you take a test – before that, it’s unlikely you’ll have enough of the pregnancy hormone hCG to give a positive result. If you can bear it, waiting a week is more likely to give an accurate result, but keep looking out for other early signs of pregnancy while you wait.