A pregnant teenager from southern Scotland has been killed by swine flu, leading to the death of her unborn child, the latest in a number of deaths around the UK.

It is understood the 17-year-old died in a hospital in the Borders yesterday but health officials have not released further details at her family's request.

Four deaths were reported in 48 hours this week in Scotland, taking the total number of deaths there from H1N1 to 15.

Health officials in Wales said today that a pregnant woman, 21, from Monmouthshire, died yesterday after being transferred to intensive care following a planned caesarean section. Three deaths have been reported in Wales in the last 24 hours.

While this virus is far milder than first feared, pregnant women are at greater risk of flu complications, alongside the elderly and those with underlying health problems.

In July Sharon Pentleton, then six months pregnant, was flown from Ayrshire for specialised treatment in Sweden after becoming critically ill with the virus. Yesterday she gave birth to a son at Crosshouse hospital in Kilmarnock.

Speaking of the death of the pregnant teenager, Nicola Sturgeon, the Scottish health secretary, said it was deeply saddening and her thoughts were with her family and friends.

"Medical experts have been telling us that pregnant women are more vulnerable to developing complications after contracting the virus."

Sturgeon urged pregnant women to take the new H1N1 vaccine when it becomes available to priority groups later this month to ensure they had "maximum protection" for themselves and their babies.

There have been 76 deaths reported in England, with 260 people in hospital last week. Four people have died in Wales and three in Northern Ireland.