Angina drugs could reduce the pain mothers experience in childbirth when their labour has to be induced.

The BBC's Paula McGrath on the Glasgow research

Researchers in Glasgow are testing glycerol trinitrate drugs on mothers whose births have to be induced.

Around a quarter of births have to be induced or started with drugs because the baby is at risk or has not arrived by its appointed date.

Normally mothers are given drugs called prostaglandins, made from hormones which occur naturally in the body, to start the labour process.

These soften up the cervix and others are used to control contractions.

However, one of their side effects is that they cause mothers pain.

About 70% of mothers say they suffer side effects using prostaglandins.

The University of Glasgow researchers say only 15% suffer side effects with the glycerol trinitrates.

They add that the drugs can sometimes help reduce the baby's distress as well.

Softening

Jane Norman, one of the researchers, said: "What we have shown in early pregnancies is that they work in a similar way to prostaglandins in terms of ripening or softening the cervix, but unlike prostaglandins they do not cause the womb to contract."

Midwife Sharon Simpson said: "Mothers [whose births are induced] can get quite distressed and the pain makes it much more difficult to cope with what is happening."

Mothers whose labour has to be induced are being asked if they want to take part in the tests.

One, Christine Croake, said she thought the trials were "a very good idea".

She welcomed anything that made childbirth easier and less traumatic.