What’s the difference between miscarriage and stillbirth?

What’s the difference? is a new editorial product that explains the similarities and differences between commonly confused health and medical terms, and why they matter.

Former US First Lady Michelle Obama revealed in her memoir she had a miscarriage. UK singer-songwriter and actor Lily Allen has gone on the record about her stillbirth.

Both miscarriage and stillbirth are sadly familiar terms for pregnancy loss. They can be traumatic life events for the prospective parents and family, and their impacts can be long-lasting. But the terms can be confused.

Here are some similarities and differences between miscarriage and stillbirth, and why they matter.

Let’s start with some definitions

In broad terms, a miscarriage is when a pregnancy ends while the fetus is not yet viable (before it could survive outside the womb).

This is the loss of an “intra-uterine” pregnancy, when an embryo is implanted in the womb to then develop into a fetus. The term miscarriage excludes ectopic pregnancies, where the embryo is implanted outside the womb.

However, stillbirth refers to the end of a pregnancy when the fetus is normally viable. There may have been sufficient time into the pregnancy. Alternatively, the fetus may have grown large enough to be normally expected to survive, but it dies in the womb or during delivery.

The Australian Institute of Health and Welfare defines stillbirth as a fetal death of at least 20 completed weeks of gestation or with a birthweight of at least 400 grams.

Internationally, definitions of stillbirth vary depending on the jurisdiction.

How common are they?

It is difficult to know how common miscarriages are as they can happen when a woman doesn’t know she is pregnant. There may be no obvious symptoms or something that looks like a heavier-than-normal period. So miscarriages are likely to be more common than reported.

Studies from Europe and North America suggest a miscarriage occurs in about one in seven pregnancies (15%). More than one in eight women (13%) will have a miscarriage at some time in her life.

Around 1–2% of women have recurrent miscarriages. In Australia this is when someone has three or more miscarriages with no pregnancy in between.

Australia has one of the lowest rates of stillbirth in the world. The rate has been relatively steady over the past 20 years at 0.7% or around seven per 1,000 pregnancies.