Pregnancy of Unknown Location

We hope that this information will help you to understand what is happening at the moment in your pregnancy.

It is important to understand that not everyone sent to the Early Pregnancy Clinic will be appropriate for an ultrasound scan. For other women, a scan may have been performed, but a pregnancy has not been seen.

How can I have a positive pregnancy test and not be able to be scanned?

Some women arrive at the clinic and are only 4 or 5 weeks pregnant by dates, so are too early for a scan to guide what should happen.

How can I have a positive pregnancy test and not be able to see the baby on scan yet?

There are three possibilities:

  • You may be very early into the pregnancy, and it is normal not to have clarity on a scan until about 6 weeks of pregnancy.
  • You may have miscarried. Some women have already had pain/bleeding before attending clinic. A pregnancy test can stay positive for up to 3 weeks following a miscarriage until hormones settle down completely.
  • Where there is no clear diagnosis by scan, this is called a pregnancy of unknown location (PUL). A small number of women with a PUL will be diagnosed with an ectopic pregnancy.

The aim of being cautious in how we look after you is to ensure we care for you safely and exclude an ectopic.

What is an ectopic pregnancy?

This is where the pregnancy grows outside of the womb - most commonly in a fallopian tube, where the pregnancy is often so small it cannot be seen on scan. There is not enough room in a tube for the pregnancy to grow, and the blood supply is not the same as in the womb, so a pregnancy can grow very slowly. An ectopic pregnancy will sadly always be a pregnancy that will not survive.

How do I find out what is happening with the pregnancy?

There are a number of things that help us to give you the answer.

  • We start by asking you questions about your symptoms.
  • You may need an abdominal and internal examination.
  • Following your scan, you will have blood tests taken for two hormones: progesterone, and the pregnancy hormone known as human chorionic gonadotrophin (hCG). Together these act as a guide for what is happening in early pregnancy. 
  • If the progesterone level is very low, the pregnancy is failing and will not continue. In most cases of failed pregnancy of unknown location, the true location of the pregnancy is never known. The majority will be failed intrauterine (in the womb) pregnancies – also called miscarriages. If your progesterone is very low, you will be advised to take a urine pregnancy test in two weeks time. If this test remains positive, then please contact the early pregnancy clinic (EPC).
  • In any other situation, we will ask you to return to EPC in two days, for another blood test for the pregnancy hormone (hCG). Please try to attend the EPC at approximately the same time of day that your first blood tests were taken and let the nurse know that you have come for a blood test so that you don’t have to wait too long. 
  • We look at whether your pregnancy hormone level (hCG) is rising or falling and use this to guide what we do next.

How long before I get any answers?

We know that this is an anxious time. Waiting and uncertainty are always difficult and stressful. Depending on your blood results, you will be advised on the next steps:

  • Your hormone levels may be increasing consistent with a normally growing pregnancy which is too early to be seen on the scan. If this happens, your scan will be repeated in one week.
  • Your hormone levels may be reducing, which suggests a failing pregnancy and likely miscarriage. If this happens, you will be asked to take a urine pregnancy test in two weeks and to call the early pregnancy clinic if this remains positive.
  • Your hormone levels may be slowly decreasing, staying the same or increasing, which may indicate an ectopic pregnancy. You will be asked to return to EPC after two days, for a repeat blood test and transvaginal ultrasound scan.

While I am waiting for results what do I need to look out for?

If you feel unwell at home in any way it is important that you call us directly.

These are the symptoms you should phone us about.

  • Bleeding – heavier than a normal period or passing large clots. 
  • Pain in your stomach – any pain that increases / does not go away after taking mild painkillers. 
  • Specific sharp pain to the right or left side.
  • Feeling faint and dizzy – especially when standing up. 
  • Pain in your shoulders.
  • Diarrhoea / loose stools (in combination with any of the above).

Any other concerns – don’t hesitate to give us a call, using the telephone number on the back of this leaflet.

If you feel very unwell, phone 999 and ask for an ambulance.

References and sources of further information

NICE guidance on ectopic pregnancy and miscarriage: diagnosis and initial management

RCOG's guidance

Early Pregnancy Information Centre

NHS Constitution - information about your rights and responsibilities

How to contact us

Early Pregnancy Clinic 
Cotswold Centre 
Southmead Hospital
BS10 5NB

EPC: 0117 414 6778
Mon–Thu  8.30am–2.30pm
Friday  8.30am–12 noon 

Cotswold Ward: 0117 414 6785/6/7/8
24 hours

Early Pregnancy Assessment Clinics (EPAC)

This edition published March 2020. Review due March 2022. NBT002001

Pregnancy of Unknown Location