Missed Abortion (Missed or Silent Miscarriage)

What missed abortion means

In medical language, "abortion" means any pregnancy that ends before 20 weeks, whether by miscarriage or by choice. A missed abortion is therefore a miscarriage, not a procedure. The pregnancy has stopped developing, but the body has not yet recognized it, so pregnancy hormones may stay high and the tissue stays in the uterus for days to weeks. Many clinics now say missed miscarriage or early pregnancy loss to avoid confusion.

There are two common forms:

• Embryonic demise: an embryo is seen but has no heartbeat.
• Anembryonic pregnancy: a gestational sac develops without an embryo, also called a blighted ovum.

Symptoms and signs

Many people have no symptoms. Possible clues include:

• pregnancy symptoms (nausea, breast tenderness, tiredness) easing suddenly
• light brown or pink spotting
• mild cramping
• a uterus measuring smaller than expected on exam

Because these changes also happen in healthy pregnancies, they cannot confirm a miscarriage on their own. Bleeding and pain usually mean the body has started to pass the pregnancy, which then becomes an incomplete miscarriage or a complete one.

Causes

About half of early pregnancy losses are caused by chromosome abnormalities in the embryo, which mean it cannot develop normally. Other factors include:

• older age of the mother (risk rises after 35)
• previous miscarriages
• uncontrolled diabetes or thyroid disease
• uterine abnormalities, such as a septum
• antiphospholipid syndrome
• smoking, heavy alcohol use and some medicines

Exercise, sex, work, lifting, stress or a fall do not cause a missed miscarriage. Most happen to people with no risk factors.

How a missed miscarriage is diagnosed

Transvaginal ultrasound is the main test. To avoid ending a pregnancy that is simply earlier than thought, clinicians use strict criteria. A pregnancy is confirmed as not viable if:

If findings are borderline, a repeat scan in 7 to 14 days is recommended. Blood hCG levels may be checked if the location of the pregnancy is unclear, to rule out ectopic pregnancy. Blood type is checked for Rh status.

Treatment options for a missed miscarriage

All three options are safe for most people. Your choice can depend on how quickly you want it to be over, your preference for home or hospital, medical factors and access.

What to expect at home

Bleeding is usually heavier than a period, with clots and strong cramps for several hours as the tissue passes, then lighter bleeding for 1 to 2 weeks. Use pads rather than tampons. Ibuprofen or acetaminophen (paracetamol) help with cramps, following the label dose or your clinician's advice. Have someone with you if possible.

Rh-negative blood type

If your blood type is Rh-negative, you may be offered an Rh immune globulin injection depending on how far along the pregnancy was and local guidance, to protect future pregnancies from Rh disease.

Testing the tissue

Pregnancy tissue is not routinely tested after a first miscarriage. Genetic testing may be offered after recurrent losses (2 or 3 or more) or for a later loss.

Recovery

• Physical: bleeding typically stops within 2 weeks. Your period usually returns in 4 to 6 weeks. A urine pregnancy test can stay positive for up to 3 to 4 weeks.
• Sex and tampons: usually fine once bleeding stops.
• Next pregnancy: you can ovulate within 2 weeks, so use contraception if you do not want to conceive. There is no medical need to wait before trying again once you feel ready, and waiting does not lower the miscarriage risk.
• Emotional: grief, guilt, anxiety and depression are common, and partners are affected too. Support organizations, counseling and your doctor can help. If you have thoughts of harming yourself, call or text 988 in the US.

Most people who have a missed miscarriage go on to have a healthy pregnancy. After one miscarriage the chance of the next pregnancy succeeding is similar to that of anyone else. Investigations are usually offered after 2 or 3 losses.

Frequently asked questions

What is a missed abortion?

It is a miscarriage in which the pregnancy has stopped developing but the tissue has stayed in the uterus. "Abortion" is the old medical term for any pregnancy loss before 20 weeks. It is also called a missed or silent miscarriage.

What are the signs of a missed miscarriage?

There are often no signs. Some people notice pregnancy symptoms fading, brown spotting or mild cramps. Most missed miscarriages are found at a routine ultrasound when the baby has no heartbeat or the sac contains no embryo.

How long can a missed miscarriage go undetected?

Without a scan, it can go unnoticed for several weeks, because pregnancy hormones can stay high and there may be no bleeding. Most eventually start to bleed and pass naturally, but timing is unpredictable, which is why many people choose medicine or a procedure.

What causes a missed miscarriage?

Most are caused by random chromosome problems in the embryo that prevent normal development. Age, previous miscarriages and some medical conditions increase the risk. Everyday activities, exercise, stress, sex and work do not cause it.

Is it safe to wait for a missed miscarriage to pass naturally?

For most people, yes, provided there is no heavy bleeding or infection and you have easy access to care. Waiting can take several weeks and may still end with medicine or a procedure. Seek urgent help for heavy bleeding, fever or severe pain.

Can a missed miscarriage be wrong?

The diagnosis is made using strict ultrasound criteria designed to avoid mistakes. If measurements fall in a borderline range, or dates are uncertain, guidelines recommend a repeat scan 7 to 14 days later before any treatment.