Threatened miscarriage: bleeding in early pregnancy and what it means

The RCOG uses the term threatened miscarriage for bleeding and/or pain in early pregnancy where an ultrasound confirms the pregnancy is progressing normally. It stresses that many women who bleed at this stage go on to have a healthy baby. The word "threatened" can sound alarming, but it describes uncertainty, not a decision that a miscarriage is happening.

The NHS defines miscarriage as loss of a pregnancy before 24 weeks, with vaginal bleeding before 24 weeks the main symptom. Other symptoms it lists are lower tummy pain and cramping, pink, grey or white lumps from the vagina and a sudden gush of fluid; sometimes there are no symptoms and a miscarriage is found at a scan.

Tommy's midwives give working definitions. Spotting is a spot or smudge on wiping, or a stain on pants, that comes and goes and can be red, pink or brown. Light bleeding stains a pad or pants more constantly but does not soak through a pad. Heavy bleeding would potentially soak through a pad; Tommy's says soaking 2 pads in an hour is a reason to seek urgent help, and that heavy bleeding is more likely to be red or dark red with possible clots.

The NHS uses similar categories: spotting, light bleeding that may need a period pad, and heavy red bleeding that soaks through a pad. It notes that bleeding can be constant or come and go, and that vaginal bleeding and tummy pain in pregnancy can be caused by things that are not always serious.

The RCOG lists your GP or midwife, your nearest Early Pregnancy Assessment Service, NHS 111, or A&E if you are bleeding heavily or in severe pain. Tommy's adds that it is a good idea not to have sex until you have been checked. The NHS says light bleeding or spotting with no pain, or only mild pain that does not stop you doing daily tasks, is a reason for urgent help: call your maternity unit if you have the number, an early pregnancy unit if you are under 20 weeks, or NHS 111.

Call 999, the NHS says, if you are pregnant and bleeding and you have severe tummy pain (you cannot do daily tasks or focus on reading or television), pain in the shoulder, feel sick, faint or dizzy or lose consciousness, or the bleeding is heavy. The RCOG gives a similar list and names heavy bleeding, severe abdominal pain, shoulder pain, dizziness or fainting as reasons to contact the early pregnancy service or A&E immediately. Early pregnancy services are organised locally, and the way you refer yourself differs across the UK nations.

The RCOG says you will be asked about your symptoms, last period, previous pregnancies and general health, and may have a urine test, an ultrasound (transvaginal, transabdominal or both), a speculum or vaginal examination, a chlamydia test and blood tests to check your blood group and the level of the pregnancy hormone hCG. You should be offered a chaperone for a vaginal examination and transvaginal scan. Neither type of scan increases your risk of miscarriage.

Tommy's explains that a heartbeat may not be visible before about 6 to 7 weeks, so the team may check the size of the pregnancy sac and that it is in the womb, which helps rule out an ectopic pregnancy, and may invite you back for another scan after 1 to 2 weeks. It says hCG is expected to roughly double every 2 to 3 days when the pregnancy is progressing, which is why repeat blood tests may be requested.

Bleeding in early pregnancy has several causes, according to the NHS and Tommy's: implantation bleeding, a collection of blood near the sac (subchorionic haematoma), changes to blood vessels in the cervix that can cause bleeding after sex, infection, miscarriage, ectopic pregnancy and molar pregnancy. The RCOG adds a pregnancy of unknown location, where a pregnancy test is positive but nothing can be seen yet on scan, which needs follow-up with blood tests every 2 to 3 days and sometimes takes up to 2 weeks to diagnose. Sometimes, the NHS says, a cause is not found.

The NHS says a miscarriage cannot be stopped once started. If the scan shows a progressing pregnancy you may be offered a follow-up scan, the RCOG says. For women who have had a previous miscarriage, the RCOG says treatment with progesterone given as a vaginal pessary will be offered and can reduce the chance of another miscarriage; whether this applies to you is a decision for your clinician. A trust leaflet from Chelsea and Westminster Hospital NHS Foundation Trust (about subchorionic haematoma) says there is no evidence for bed rest but recommends avoiding strenuous activity and sexual intercourse while bleeding, and advises contacting the early pregnancy unit if bleeding is still present 14 days after the scan or is getting worse. Policies differ between units, so follow your own unit's advice.

If your blood group is rhesus negative and you bled after 12 weeks, the Chelsea and Westminster leaflet says an anti-D injection will be offered. For a miscarriage after 12 weeks, the NHS says an anti-D injection may be offered to prevent haemolytic disease in later pregnancies.

The RCOG says about one in five women have a miscarriage in the first 3 months following a positive test, and that the risk rises with age: one in five (20%) at 30 and one in two (50%) over 40. The most common cause is thought to be a chromosome problem in the baby. It says there is no evidence that stress causes miscarriage or that sex during pregnancy is associated with early miscarriage. The NHS lists options for early miscarriage as waiting, medicine or a procedure under anaesthetic, and says that most women who miscarry go on to have a successful pregnancy; talk to a GP if you have had 3 or more miscarriages. Miscarriage UK and Tommy's offer support lines.