Information alert

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The purpose of this information is to:

  • Describe what a pregnancy of unknown location (PUL) is
  • Discuss what it means for your pregnancy and your health
  • Explain what we do to locate the pregnancy and assess whether it is developing normally

A pregnancy of unknown location (sometimes referred to also as an ‘inconclusive scan’) is when you have a positive pregnancy test but the pregnancy cannot be seen on ultrasound scan. It occurs in about 10% of the women who attend our early pregnancy unit. If we are unable to see the pregnancy we cannot confirm that the pregnancy is in the right place or that it is developing normally.

Pregnancy of unknown location is a medical label rather than diagnosis and is used until the development and location of pregnancy can be confirmed. We aim to do this as quickly as possible.

There are several possibilities as to why we cannot see a pregnancy on ultrasound:

1. It might be too early to see the pregnancy.

Urine pregnancy tests can now detect pregnancy very early. However, it will take about a week from when a pregnancy test becomes positive to when one can expect to see the pregnancy on ultrasound. Therefore, it may be that the pregnancy is in the womb but is too small to be seen on scan.

2. The pregnancy may have already miscarried.

If you have experienced heavy bleeding, similar to a period or perhaps heavier, the pregnancy may already have passed. However, a pregnancy test can still be positive because the pregnancy hormones (detected by the urine or blood test) take a while to gradually disappear. A urine pregnancy test can remain positive for up to 3 weeks after a pregnancy loss and you might continue to ‘feel’ pregnant during this time.

3. You may have an ectopic pregnancy.

An ectopic pregnancy occurs when the pregnancy has implanted outside of the cavity of the womb. Ectopic pregnancies can be more difficult to find on an ultrasound scan than pregnancies that have implanted correctly within the womb.

We will firstly need to take blood tests from you to measure two hormone levels: the pregnancy hormone Human chorionic gonadotrophin (hCG) and another hormone called progesterone. Depending on the time you have your blood taken, we will call you with the results either the same day or the following morning. The blood tests may not give a final answer as to what is happening but they will help us decide what to do next.

Follow-up usually involves one of the following:

  • A repeat blood test, usually after two days
  • A repeat ultrasound scan
  • A repeat home pregnancy test in one week
  • Telephone follow up from our nursing team.

The length of follow-up can vary depending on your results. While you are under follow-up in our clinic, you can contact us on the numbers at the end of this information if you have any questions or concerns.

Having assessed you, we believe that you are well enough to go home today. It is important however, to remember that during the time that we do not know where your pregnancy is located we cannot rule out an ectopic pregnancy. Therefore, it is very important that you attend hospital immediately if you develop worsening tummy pain, diarrhoea, shoulder pain or have fainting episodes.

If you experience bleeding, you do not need to seek urgent medical attention unless it is very heavy. However, please inform the nurses of any change in symptoms.

Most miscarriages are caused by a fault on a chromosome (a package of genes) within the cells of the developing pregnancy. This means that the pregnancy is not healthy and is not developing normally. This cannot be prevented and it is not caused by anything you have done or not done.

Having to attend an early pregnancy unit can be a worrying time and not knowing what is happening can make this even worse. Women and their partners can have different emotional reactions to what is going on. If these feelings are severe or if you feel that you need help in coming to terms with what you are experiencing it may help to talk to a professional and you should see your GP.

The Miscarriage Association

Telephone: 01924 200 799

The Ectopic Pregnancy Trust

Telephone: 020 7733 2653 

SANDS (Stillbirth, Miscarriage and Neonatal Death Support)

Telephone: 020 7436 5881 


UCLH cannot accept responsibility for information provided by other organisations.


The Patient Advice and Liaison service (PALS) is a service which offers support, information and assistance to patients, relatives and visitors.

Telephone: 020 3447 9975


Address: PALS, Ground Floor Atrium, University College Hospital, 235 Euston Road, London, NW1 2BU

Early Pregnancy Unit Senior Nurses

Direct line: 020 3447 6515 (Please leave a voicemail)

Switchboard: 020 3456 7890(or 0845 155 5000 - premium call rates apply)

Extension: 76515

Bleep (pager): 3527

*Please note that phone calls from our hospital will display as an unknown number

Opening Times:

Monday to Friday 09:00 - 12:30 and 14:00-16:30

Saturday and Sunday 09:00 - 12:30 (A&E referral only)

Early Pregnancy Unit

Elizabeth Garrett Anderson Wing Clinic 3,

Lower Ground floor 235 Euston Road London, NW1 2BU






































Page last updated: 28 May 2024

Review due: 31 May 2024