A simple test could tell women their chance of miscarriage just days after they conceive, a study suggests.
One in four pregnancies fail with rates of miscarriages rising substantially among older women.
But now research has found that measuring hormone levels soon after conception can provide information about how viable the pregnancy is.
Glasgow scientists examined the levels of the hormone beta-human chorionic gonadotropin in more than 2,000 women who had just had a positive pregnancy test.
The hormone is specifically produced during pregnancy. It is made by cells formed in the placenta, which nourishes the egg after it has been fertilised and becomes attached to the uterine wall. In a healthy pregnancy, levels of it rise speedily during the first trimester.
The researchers found that those with the highest rates of the hormone had an 86 per cent chance of a successful pregnancy, when scanned eight weeks later.
This dropped to a two percent chance among those with the lowest levels of the hormone, the study by GCRM, part of the Fertility Partnership, found.
Experts at the European Society of Human Reproduction and Embryology conference in Geneva said the knowledge would help patients to prepare "psychologically and emotionally" for experiences which could be devastating.
Most miscarriages occur in the early months of pregnancy, though a small number happen later.
Marco Gaudoin, medical director at GCRM said: "Couples undergoing IVF wait two weeks to discover if they have conceived, yet for some this will not lead to a live birth.
"The [hormone] level gives us a clear guide, helping us to counsel patients about the likelihood of a miscarriage, which in turn will help us to better prepare patients psychologically and emotionally."
Ruth Bender Atik, national director for the Miscarriage Association said: "These results mean that IVF patients and clinicians now have the opportunity to learn more about the likely outcome of treatment beyond the joyful news of a positive pregnancy test.
"That development is to be welcomed as long as it is managed sensitively, with patients able to make an informed choice regarding testing."
- The Telegraph, London