Pregnancy bleeding – why it can happen

Bleeding in pregnancy can be harmless, but you should know when to take action


Bleeding in early pregnancy 

Common causes: ‘Bleeding in the first trimester is pretty common,’ says Patrick O’Brien, consultant obstetrician at University College Hospital, London.


‘Many women fear a miscarriage, but it’s not necessarily the case and for most women it will settle down and stop.’

One reason for early bleeding is implantation: when the fertilised egg implants into the lining of the uterus. This happens in the first week or two, often causing a slight bleed.

When it might be serious: Bleeding in the first trimester can sometimes signal an ectopic pregnancy – where the embryo grows in the Fallopian tube – or a threatened miscarriage.

‘As a general rule, the heavier the bleeding, the more worrying,’ says Patrick.

What to do: Report any bleeding to your GP or midwife. If bleeding is heavy, go to the early pregnancy unit at your local hospital. A scan and sometimes a blood test will determine if all is well.

Bleeding in mid to late pregnancy

Common causes: There is less chance of bleeding after 13 weeks of pregnancy. If it does occur, it could be caused by cervical erosion, where the cervix becomes fragile, sometimes resulting in bleeding after sex.

‘This is due to the extra oestrogen produced during pregnancy, and isn’t the slightest bit risky to mother or child,’ says Patrick.

Blood-tinged mucus close to your due date is likely to be a ‘show’: the plug that seals the cervix coming away in preparation for labour.

When it might be serious: Bleeding in the second and third trimesters can be caused by placenta praevia, where a low-lying placenta covers or comes close to the cervix.

‘This bleeding is usually painless,’ says Patrick. If it’s a small one-off bleed, you’re likely to be offered extra check-ups.

Placenta praevia can, however, cause severe bleeding, in which case a Caesarean is usually necessary as the placenta is blocking the baby’s access to the birth canal.

Bleeding accompanied by continuous abdominal pain could indicate placental abruption, where the placenta separates from the wall of the uterus. This is unusual but can be serious – if a lot of the placenta comes away, it can stop oxygen getting from the mother to the baby. A Caesarean is likely to be necessary.

BABY EXPERT ADVISES: Seek immediate help for any bleeding. If it is heavy, go straight to hospital – call an ambulance if necessary. Once the cause of the bleeding is established, you will be in the right place to get the right treatment, whether it’s monitoring, bed rest or a Caesarean.


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