Bleeding is the one entry in this A–Z whose answer does not depend on the details. Some causes are entirely harmless and some are emergencies, and the problem is that at the moment it happens they can look the same. So the rule is simple and unconditional — and the rest of this page explains what is behind it, because "ring someone" without a reason gets ignored at three in the morning.
Call emergency services now if: bleeding is heavy — soaking a pad in an hour or less, or passing large clots; there is severe abdominal pain, especially one-sided or with pain at the tip of your shoulder; you feel faint, dizzy, cold or clammy; or your abdomen is hard and constantly painful.
Call your maternity unit or early pregnancy unit the same day for any other bleeding, at any stage. Including light spotting. Including if it has already stopped.
Causes by trimester
| Cause | When | What it typically looks like |
|---|---|---|
| Implantation bleeding | Around 4 weeks | Light spotting, pink or brown, a day or two, around when a period was due |
| Cervical bleeding | Any stage | Light spotting after sex or an internal examination; settles within hours |
| Miscarriage | Mostly T1 | Bleeding that increases, cramping, sometimes clots or tissue |
| Ectopic pregnancy | T1 | Bleeding with severe one-sided pain, shoulder-tip pain, faintness — emergency |
| Placenta praevia | T2–T3 | Painless bleeding, can be sudden and heavy, often bright red |
| Placental abruption | T2–T3 | Constant severe pain, hard tender abdomen, bleeding that may be light or hidden — emergency |
| The show / mucus plug | Near term | Blood-streaked jelly-like mucus, not flowing blood |
Two things stand out from that table. Abruption can bleed very little visibly while being serious, so the amount of blood is a poor guide on its own — pain is a better one. And praevia bleeds without pain, so the absence of pain is not reassurance either. Between them they are why neither symptom alone decides anything.
What to note before you ring
- How many weeks you are.
- How much — spotting on wiping, or soaking through a pad, and over what period.
- What colour — bright red, brown, pink, or mucus streaked with blood.
- Whether there is pain, where it is, and whether it is constant or in waves.
- Movements, if you are past around 24 weeks — reduced movements alongside bleeding raises the urgency.
- Your blood group. If you are rhesus negative you may need anti-D after bleeding, and there is a time window for it.
Do not use a tampon to manage bleeding in pregnancy, and do not have sex until you have been assessed. Use a pad — it also lets whoever sees you judge the volume.
Vaginal bleeding in pregnancy — at a glance
Bleeding in pregnancy has causes ranging from entirely harmless to immediately life-threatening, and they are not reliably distinguishable at the moment they happen — which is why the rule is unconditional: all bleeding at any stage is reported and assessed, including light spotting and including bleeding that has stopped. In the first trimester the causes are implantation bleeding, a more vascular cervix bleeding after sex, miscarriage, and ectopic pregnancy, which brings severe one-sided pain, shoulder-tip pain and faintness and is an emergency. Later they are placenta praevia, which bleeds painlessly and can be heavy, placental abruption, which brings constant severe pain and a hard tender abdomen and may bleed very little visibly, and near term the blood-streaked mucus plug. Because abruption can conceal blood and praevia can be painless, neither the amount of bleeding nor the absence of pain is reassurance on its own. Note gestation, volume, colour, pain, fetal movements and your blood group before ringing — rhesus-negative women may need anti-D, and it has a time window.
Inside Baby Novum: gestational week, scan results and blood group sit together in one record. Every one of them is something you will be asked for, and none of them is easy to retrieve accurately while frightened. Encrypted on the device, no account, no server copy.
Frequently Asked Questions
Is any bleeding in pregnancy normal?
Some bleeding is harmless — light implantation spotting in very early pregnancy, spotting after sex or an internal examination from a more vascular cervix, and the blood-streaked mucus plug near term. But harmless and urgent bleeding can look identical at the time, so the rule is unconditional: all bleeding in pregnancy is reported and assessed. Most assessments end in reassurance, and that is the expected outcome rather than a waste of anyone's time.
What causes bleeding in the first trimester?
Implantation bleeding around the time a period would have been due; a cervix that bleeds more easily after sex; miscarriage, which is common and usually not preventable; and ectopic pregnancy, where the pregnancy implants outside the uterus. The last of those is the emergency, and it typically brings severe one-sided pain, shoulder-tip pain, faintness or feeling very unwell alongside the bleeding.
What causes bleeding later in pregnancy?
A low-lying placenta (placenta praevia), which classically bleeds painlessly and can be heavy; placental abruption, where the placenta separates early, usually with constant severe pain and a hard tender abdomen; cervical causes; and, near term, the mucus plug or "show", which is blood-streaked mucus rather than fresh bleeding. Any bleeding after 24 weeks is assessed the same day.
Does bleeding mean I am having a miscarriage?
Not necessarily. Bleeding in early pregnancy is common and many pregnancies with it continue entirely normally. What raises concern is heavy bleeding, passing clots or tissue, and severe cramping. An early pregnancy unit can usually clarify quickly with a scan and blood tests, and clarity — either way — is worth having sooner.
What will happen when I ring?
You will be asked how many weeks you are, how much you are bleeding and what colour, whether there is pain, whether you have felt the baby move if you are far enough along, and your blood group — anti-D is given after bleeding to people who are rhesus negative, which is one specific reason not to wait. Depending on the answers you may be seen the same day, scanned, or monitored.