An ectopic pregnancy can be diagnosed by examination, ultrasound scan, and blood tests. It can be difficult to rule out ectopic pregnancy in very early pregnancy, especially if the pregnancy cannot be seen on a scan yet. In this case your healthcare provider will organise for another scan and blood tests to keep an eye on the situation.
If your healthcare provider suspects an ectopic pregnancy, but it's too early to tell, you need to look out for warning signs like: bad pain, heavy bleeding, feeling faint or dizzy, or shoulder tip pain. If you have any of these signs you should go straight to hospital.