The blood test could result in earlier diagnosis of the condition – where the egg implants in the wrong place – cutting the need for radical surgery.
The test checks for abnormalities that signal an ectopic pregnancy after just a few weeks, when a simple injection can deal with the problem.
It is currently undergoing trials and is being backed by the NHS, which could mean it will be used to help patients within a year.
In an ectopic pregnancy the fertilised egg implants outside the womb, usually in one of the two fallopian tubes. The foetus must then be removed surgically, sometimes with the tube as well, which halves the chances of getting pregnant again.
It is often not diagnosed for several weeks until symptoms develop into a medical emergency that can be life-threatening.
At present, blood screening and ultrasound are used to detect abnormalities but these methods are not accurate in the early stages after conception and women may need several hospital appointments to confirm an ectopic pregnancy before being admitted for an operation.
But the new test requires only one visit after which women with the condition can be treated on an outpatient basis with the fallopian tube being preserved.
It is being backed by NHS Innovations, the agency which identifies potential breakthroughs and helps introduce them into the health service.