Miscarriage: what actually happens, and what to know

About 10–20% of known pregnancies end in miscarriage. The true rate is higher — many pregnancies end before a person knows they're pregnant, sometimes presenting as a late or heavy period. It's the most common complication of early pregnancy, and it's one of the least discussed.

What causes most miscarriages

The majority of early miscarriages (those before 12 weeks) are caused by chromosomal abnormalities in the embryo — errors that occurred during fertilisation or early cell division that make normal development impossible. These aren't caused by anything the pregnant person did or didn't do. Not the run you went for. Not the coffee you had. Not the stress at work. The body ends a pregnancy that couldn't continue.

Other causes include structural problems with the uterus, clotting disorders, thyroid conditions, and infections — but these are less common than chromosomal causes and more often associated with recurrent (repeated) miscarriage rather than a single pregnancy loss.

Recognising a miscarriage

The most common sign is vaginal bleeding, which may range from light spotting to heavier flow. Cramping often accompanies it. Some miscarriages are only discovered at a scan, with no symptoms — this is sometimes called a missed or silent miscarriage, where the embryo stopped developing but the body hasn't yet recognised it.

Spotting alone in early pregnancy doesn't necessarily mean miscarriage — it's common and often has benign causes. But any bleeding in pregnancy warrants contact with a healthcare provider.

What happens medically

There are three common approaches to managing a miscarriage, depending on the stage and circumstances. Expectant management means waiting for the body to complete the process naturally, which usually takes one to two weeks. Medical management uses medication (typically misoprostol) to help the uterus expel the pregnancy. Surgical management — either manual vacuum aspiration or a procedure called ERPC (evacuation of retained products of conception) — is done when the other approaches aren't working or aren't appropriate.

All three are legitimate options with similar outcomes in most cases. The choice depends on how far along the pregnancy was, whether there are complications, and what the person prefers.

When will cycles return to normal?

Most people have a period within 4–6 weeks of a miscarriage. Ovulation typically returns before the first period, meaning conception can happen again before you've had a chance to track a full cycle. Most medical guidance now is that there's no need to wait before trying again, unless there was a specific complication. The evidence that waiting improves outcomes is limited.

Recurrent miscarriage

Recurrent miscarriage is defined as three or more consecutive pregnancy losses, though many specialists begin investigation after two. About 1–2% of couples experience recurrent miscarriage. Investigation includes chromosomal testing of both partners, uterine anatomy assessment, blood clotting tests, and thyroid function testing. In about half of cases investigated, no cause is found — which is frustrating but doesn't mean the next pregnancy won't succeed.

This article is general information only. If you're going through a pregnancy loss, please reach out to your healthcare provider.