Miscarriage Dr Trisha Macnair A miscarriage is a pregnancy that ends naturally before the unborn child can survive. This is usually considered to be before about the 24th week, although some babies born at 23 weeks now survive.

In this article

What causes it? What are the symptoms?

How many women are affected? Advice and support

There are many causes of miscarriage but the commonest cause of sporadic miscarriage (meaning it's a one-off event rather than a recurrent problem) is a genetic abnormality in the embryo or foetus.

Miscarriage is not caused by lack of rest, lifting, stress, constipation, normal exercise or sex.

Problems with one or more genes may cause miscarriage, but are more likely to result in a baby born live but with a medical problem. Half of all early miscarriages are caused by chromosomal abnormalities in the foetus. Most of these arise out of the blue (a spontaneous mutation) but in a small number there's a condition in the parent known as a translocation.

Because miscarriage is common and most women go on to have a normal pregnancy later, a cause isn't usually sought until a woman has suffered three. Then tests may be done, including examination of tissue samples from the miscarried foetus.

The signs of a miscarriage are the onset of bleeding, usually with abdominal cramps (like a period) in a woman who's pregnant - although in early miscarriage she may not yet be aware she's pregnant.

The bleeding may be heavy, with clots, and sometimes a creamy coloured sac of membranes is passed, which may contain a tiny embryo.

Miscarriage can be emotionally devastating and cause prolonged exhaustion.

Miscarriage is common - one in four women who becomes pregnant will experience at least one miscarriage and some lose many babies (about one in 100 women suffers recurrent miscarriages).

Many more pregnancies are lost at such an early stage that the mother doesn't even realise she's pregnant. In fact, one estimate suggests 60 per cent of all conceptions, or potential pregnancies, are lost.

Miscarriage is more common in older women, especially those over 35, and women who smoke.

The Miscarriage Association
Helpline: 01924 200799 (Scotland: 0131 334 8883)
Website: www.miscarriageassociation.org.uk

Sands (Stillbirth and Neonatal Death Charity)
Helpline: 020 7436 5881
Email: helpline@uk-sands.org
Website: www.uk-sands.org/

This article was last medically reviewed by Dr Rob Hicks in May 2008