Symptoms of an ectopic pregnancy usually develop between the 4th and 12th weeks of pregnancy.
Some women don't have any symptoms at first. They may not find out they have an ectopic pregnancy until an early scan shows the problem or they develop more serious symptoms later on.
Contact your GP or call NHS 111 if you have a combination of any of these symptoms and you think you might be pregnant – even if you haven't had a positive pregnancy test.
Vaginal bleeding tends to be a bit different to your regular period. It often starts and stops, and may be watery and dark brown in colour.
Some women mistake this bleeding for a regular period and don't realise they're pregnant.
Vaginal bleeding during pregnancy is relatively common and isn't necessarily a sign of a serious problem, but you should seek medical advice if you experience it.
You may experience tummy pain, typically low down on 1 side. It can develop suddenly or gradually, and may be persistent or come and go.
Tummy pain can have lots of causes, including stomach bugs and trapped wind, so it doesn't necessarily mean you have an ectopic pregnancy.
But you should get medical advice if you have it and think you might be pregnant.
Shoulder tip pain is an unusual pain felt where your shoulder ends and your arm begins.
It's not known exactly why it occurs, but it can be a sign of an ectopic pregnancy causing some internal bleeding, so you should get medical advice right away if you experience it.
You may experience pain when going for a pee or poo. You may also have diarrhoea.
Some changes to your normal bladder and bowel patterns are normal during pregnancy, and these symptoms can be caused by urinary tract infections and stomach bugs.
But it's still a good idea to seek medical advice if you experience these symptoms and think you might be pregnant.
In a few cases, an ectopic pregnancy can grow large enough to split open the fallopian tube. This is known as a rupture.
Ruptures are very serious, and surgery to repair the fallopian tube needs to be carried out as soon as possible.
Signs of a rupture include a combination of:
Call 999 for an ambulance or go to your nearest accident and emergency (A&E) department immediately if you experience these symptoms.