Threatened Miscarriage and Early Bleeding

What "threatened miscarriage" means

It is a description, not a prediction. The RCOG defines it precisely: "If you have had bleeding and/or pain but your ultrasound scan confirms that your pregnancy is progressing normally, this is known as a threatened miscarriage. Many women who bleed at this stage of pregnancy go on to have a healthy baby."

The word "threatened" is doing a lot of unhelpful emotional work. In clinical use it simply records that there has been bleeding and the pregnancy is still there.

The RCOG also frames the baseline honestly: "Vaginal bleeding and/or cramping pain in the early stages of pregnancy are common and do not always mean that there is a problem. However, bleeding and/or pain can be a warning sign of a miscarriage or, less commonly, of other complications of early pregnancy."

What early bleeding can turn out to be

The RCOG's early pregnancy leaflet lists the possibilities that an assessment is trying to separate:

• Threatened miscarriage — bleeding with an ongoing pregnancy on scan.
• Early miscarriage — common; the RCOG gives one in five in the first three months after a positive test.
• Ectopic pregnancy — the RCOG gives one in 90 UK pregnancies.
• Molar pregnancy — uncommon; the RCOG gives about one in 700 pregnancies.
• Pregnancy of unknown location (PUL) — a positive test with nothing visible on scan yet.

PUL is the one that generates the most anxiety, so it is worth quoting the RCOG's explanation in full. It may be that the pregnancy is in the womb but too early to see: "a pregnancy may not be seen on ultrasound until approximately 3 weeks after conception (at least 5 weeks from your last period)." It may be an early miscarriage that has already happened, since tests can stay positive for a week or two. Or it may be an ectopic too small to see — and the RCOG says that "as many as one in five women with a PUL may have an ectopic pregnancy".

Nobody can shortcut that. The RCOG says the follow-up is usually blood tests every 2 to 3 days and another scan within 1 to 2 weeks, and that reaching a diagnosis "may take up to 2 weeks".

When to get help urgently

The RCOG says to contact your early pregnancy assessment service or emergency department immediately if you have any of:

• heavy bleeding
• severe pain in your abdomen
• pain in your shoulders
• dizziness
• fainting

Those are the signs of an ectopic pregnancy, and they override everything else on this page. The NHS adds that if bleeding is soaking a period pad soon after putting it on, that is an emergency call, not a wait-and-see.

For lighter bleeding, the NHS still advises contacting your maternity unit or, if you are under 20 weeks, an early pregnancy unit. ACOG's patient guidance takes the same line: bleeding in pregnancy should be reported to your obstetric team.

What happens at the early pregnancy unit

The RCOG lists what to expect: questions about your symptoms and last period, a urine pregnancy test, an ultrasound scan (transvaginal or abdominal, sometimes both), possibly a speculum or vaginal examination to look at the cervix, a chlamydia test, and blood tests for your blood group and hCG level. You should be offered a chaperone for any internal examination or transvaginal scan, and you can bring someone with you.

The blood group test is not incidental — it determines whether you need anti-D, and that decision now depends on exactly how many weeks you are.

Progesterone: who it is actually for

This is the one treatment with a specific NICE recommendation behind it, and it is narrower than most people assume.

NICE recommendation 1.9.2: "Offer vaginal micronised progesterone 400 mg twice daily to women with an intrauterine pregnancy confirmed by a scan, if they have vaginal bleeding and have previously had a miscarriage." Recommendation 1.9.3 adds: "If a fetal heartbeat is confirmed, continue progesterone until 16 completed weeks of pregnancy."

Both conditions matter. NICE's committee explains that there was good evidence of benefit for that specific group, but "evidence of no benefit in women with early pregnancy bleeding but no previous miscarriage, nor in women with previous miscarriage but no early pregnancy bleeding in the current pregnancy". There was no evidence of benefit for other preparations or doses.

NICE also explains why the scan comes first: progesterone is only given once an intrauterine pregnancy is confirmed, to reduce the risk of giving it to someone with a pregnancy of unknown location or an ectopic pregnancy.

If you have bled and have no history of miscarriage, NICE's advice is different: return for further assessment if bleeding gets worse or persists beyond 14 days, and if it stops, start or continue routine antenatal care.

Anti-D, and what changed

NICE updated its anti-D recommendations for early pregnancy in June 2026, and the thresholds are now gestation-specific. NICE recommendation 1.18.1 says not to offer anti-D immunoglobulin for an ectopic pregnancy, miscarriage or threatened miscarriage "up to and including 11+6 weeks' gestation". For threatened miscarriage at 12+0 to 12+6 weeks with heavy or recurrent bleeding, NICE says to consider anti-D at a dose of at least 250 IU (50 micrograms). Where ultrasound and last menstrual period disagree, NICE says use the ultrasound dating.

That is UK guidance. Practice elsewhere differs — ACOG's patient information sets a 12-week line too but frames earlier losses as a discussion to have with your own clinician.

What does not help

There is no good evidence that bed rest changes the outcome of early bleeding, and no national guideline recommends it. There is no evidence that stress causes miscarriage, and the RCOG says so directly. Sex is not associated with early miscarriage either, though you may reasonably want to avoid it while you are bleeding.

The honest position is that most early bleeding resolves one way or the other without anything you do changing it, and that the interval before you know is genuinely awful. Miscarriage UK, formerly the Miscarriage Association, runs a support line for exactly this stage — not only after a loss is confirmed. Tommy's has a midwife line that will also take calls during the waiting.