Women who experience bleeding in early pregnancy and have had at least one miscarriage should be treated with the hormone progesterone.
The new guidance, from the National Institute for Health and Care Excellence (NICE), is based on research suggesting the treatment could lead to 8,450 more births each year in the UK.
The more miscarriages a woman had, the more effective progesterone was, the trial found. The naturally occurring hormone helps prepare the womb for the growing baby.
About one in five women experience bleeding, or spotting as it is sometimes called, in the first 12 weeks of pregnancy. It often causes no problems but they are advised to have it checked out with their doctor or midwife to be sure.
Some may experience a "threatened miscarriage", where bleeding continues along with the pregnancy. Most are told to go home and wait and see what happens next.
The new (NICE) guidance recommends inserting progesterone pessaries into the vagina twice a day.
A trial carried out by researchers at the Tommy's National Centre for Miscarriage Research which the new guidance is based on, found that progesterone didn't make much of a difference for women who just had bleeding and no previous miscarriages. But the more miscarriages a woman had suffered, the more effective progesterone was.
One of those behind the Tommy's National Centre for Miscarriage Research research, Prof Arri Coomarasamy, from the University of Birmingham, said: "This is a very significant moment.
"We have an intervention that works that can stop a miscarriage. This gives hope to thousands of couples throughout UK."
"But it's really important to appreciate that only some miscarriages can be prevented by progesterone."
"There are other causes for miscarriages."
"We still need to study them. We need to find other effective treatment."
Source: BBC News, 24 November 2021