Bleeding during pregnancy: Common causes

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  • Bleeding in pregnancy is one of the scariest things that can happen to a pregnant woman. But it doesn’t necessarily mean that there’s a problem.

    If you’re pregnant and have experienced some bleeding or spotting then there could be lots of possible explanations. Here are some of the most common causes…

    Sex or internal exam

    During pregnancy there’s an increased blood supply to the cervix and you may experience a small amount of spotting after sex or an internal examination. This is very common and it can be pink, red or brown.

    Miscarriage or ectopic pregnancy

    Blood loss in pregnancy can be a sign of miscarriage or an ectopic pregnancy, especially if accompanied by pain or cramps. Any bleeding in early pregnancy is often referred to as a ‘threatened miscarriage’. You can contact your midwife, who should be able to arrange an ultrasound scan.

    Bed rest used to be advised for women who bleed in early pregnancy, but there’s no evidence that this makes any difference to the outcome. In any case, for reassurance contact your midwife.


    Spotting can also be caused by conditions unrelated to pregnancy. A vaginal infection (such as thrush or bacterial vaginosis) or a sexually transmitted infection (such as trichomoniasis, gonorrhoea, chlamydia, or herpes) can cause inflammation in the cervix. Your midwife can take a swab to check for infection.

    Implantation bleed

    Symptoms of early pregnancy can be similar to the way you feel when your period’s due. You may get a little breakthrough bleeding or ‘spotting’, called an implantation bleed, 6-10 days after conception, as the fertilised egg embeds itself in the womb lining.

    In the first few weeks, some women find they have a light bleed around the time their period would have been due.

    Placental problems

    In the second or third trimester, bleeding can be a sign of a condition such as placenta praevia (where the placenta covers the cervix, blocking the baby’s way out) or placental abruption (in which the placenta separates from the uterus) and should be checked out straightaway.

    If you have an ultrasound scan, the position of the placenta will be remarked on. Women with a low-lying placenta will be advised to go to the labour ward if they have any bleeding in their pregnancy, to check that everything is okay.

    Normal labour

    The mucus plug or ‘show’ that women usually experience before labour starts is often streaked with blood. If this occurs after 37 weeks, it’s most likely just a sign that the cervix is beginning to soften or dilate in preparation for labour.


    In many cases, the cause of bleeding in pregnancy is unknown, and women go on to full-term with no complications. It’s still best to report any bleeding in pregnancy to your midwife, though, or to contact the labour ward if you need to speak to a midwife urgently.


    It’s important to know your blood group, as if you’re Rhesus positive and have a bleed after the 12th week of pregnancy, you’ll be advised to have an injection of Anti-D within 72 hours. This prevents your body from developing antibodies that may cause problems in future pregnancies.

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