What causes bleeding in early pregnancy?

Pregnancy increases blood flow to the cervix, and cervical ectropion can make its surface bleed more easily, including after sex or an examination. Some people have light spotting around the time a period would have been due. Bleeding can also be a presentation of miscarriage, including a missed miscarriage where pregnancy loss is not immediately accompanied by symptoms. An ectopic pregnancy develops outside the womb and can cause bleeding with one-sided pelvic pain, shoulder-tip pain, dizziness, or fainting. The amount and colour of blood do not reliably identify the cause.

Contact a maternity or medical service as soon as you notice bleeding, even when it is light. Describe the timing, amount, colour, clots, pain, and any previous pregnancy concerns. Assessment may involve an examination, pregnancy hormone testing, and an ultrasound; the timing of tests can depend on how far along the pregnancy may be. Use pads rather than tampons while waiting for advice, and avoid driving if you feel faint.

Go to emergency care for severe or one-sided abdominal pain, shoulder-tip pain, fainting, severe dizziness, heavy bleeding, or feeling very unwell. These symptoms can signal internal bleeding or another urgent pregnancy complication. Ask for immediate help if you cannot keep fluids down or develop a fever with pelvic pain.

Could the bleeding be from the cervix or a pregnancy complication? Do I need serial hormone tests or an ultrasound? Which symptoms mean I should go straight to emergency care? What follow-up will confirm whether the pregnancy is developing normally?