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Pregnancy of unknown location / Inconclusive scan

What is a pregnancy of unknown location / Inconclusive scan?

If you have a positive pregnancy test but we have been unable to see the pregnancy with an ultrasound scan it is called a ‘Pregnancy of Unknown Location’ (PUL)/Inconclusive scan. We know this may be confusing at first and hope this leaflet helps to clarify things.

What does that mean?

In this situation there are three possible scenarios.

  • The pregnancy is too early to see on scan

Over the counter pregnancy tests can sometimes detect the pregnancy hormone before your next period is due. However, a pregnancy may not be seen on ultrasound until approximately 3 weeks after conception (about 5 weeks from your period). So women sometimes attend when it is too early for us to see anything on ultrasound scan.

  • An early miscarriage has occurred

If you have had bleeding it could be that an early miscarriage has occurred so that the pregnancy can no longer be seen within the uterus (womb) because it has already been passed.

Sometimes the pregnancy isn’t growing at a normal rate, so it takes a longer time to see it and it ends as a miscarriage.

  • The pregnancy is outside the womb (uterus), most commonly in the fallopian tube – an ectopic pregnancy

This is the least likely possibility but if ignored an ectopic pregnancy is potentially life threatening. We need to treat all women as if they might have an ectopic pregnancy until we confirm a miscarriage with blood tests, or confirm a pregnancy seen developing within the womb.

What happens next?

To help us find out where the pregnancy is developing, we need to look at the pregnancy hormone (hCG) level and how much it increases over a 48-hour period. This may be repeated after 48 hours. It is important that these tests are done at the right time to help us establish the nature of the pregnancy and plan the best course of action. We may also look at another ovarian hormone (progesterone) which complements the hCG levels. In a very small number of women, we do not repeat blood tests and only advise a repeat urine pregnancy test in 2-3 weeks.

  • In a normal pregnancy that is in the womb (uterus) we expect the hCG hormone level to approximately double every 48 hours.
  • In an ectopic pregnancy (and in failing pregnancies in the womb) the hCG hormone level often does not double but rises or falls slightly or stays the same.
  • If a miscarriage has occurred, the hCG hormone level usually falls rapidly.

How we arrange follow-up?

If the hCG level has dropped significantly a miscarriage is likely to have occurred. In this situation we will normally ask you to check a home pregnancy test in 2-3 weeks. A further telephone consultation will take place at that time and we you will be asked to do a pregnancy test before the call.

You may be required to attend for a further scan and blood test if the pregnancy test is still positive.

Where the pregnancy hormone is increasing rapidly it is more likely the pregnancy is developing in the womb and we will normally see you for a further scan over the next coming days.

If the level is neither rising nor falling significantly, we need to monitor you more closely for signs of an ectopic pregnancy. This will involve further scans and blood tests

What might you expect in the next few days?

Depending on your own individual clinical situation, you might experience bleeding at home. This might be light or even quite heavy (but not more than a period or passing large clots). Even though we did not see an actual pregnancy on the ultrasound scan, the womb lining may still be quite thickened, and this can seem like ‘tissue’ when passed.

Many women will also experience some mild or moderate period type cramps if the pregnancy is unfortunately not successful (a miscarriage). But in all such cases the pain should settled with mild painkillers.

Important points

Every woman is assessed individually according to their symptoms and scan findings and the above notes are just guides to what you might expect. It is important that you attend all your follow-up blood tests to help us diagnose the outcome of your pregnancy.

We will advise you about follow up as necessary. Avoid any air travel until the location of your pregnancy has been confirmed. Review all travel plans so in an emergency you can access urgent medical care, ideally with the hospital specialists who know you best.

Who should I contact for advice or help?

We know this can be a stressful time when advised you have a pregnancy of unknown location. If you have any further questions or you are worried you should contact your local Early Pregnancy Unit. We may advise professional emotional support, or to see your GP. Our contact details are overleaf.

Who should I contact in an emergency?

  • Bleeding – heavier than a normal period or passing large clots
  • Offensive discharge – if the bleeding become smelly or you think you have a fever
  • Sharp pain in your abdomen – any pain that increases or does not settle with mild painkillers.
  • Feeling faint and dizzy
  • Pain in your shoulders
  • Diarrhoea / loose stools (in combination with any of the above).

If you have any concerns or you feel unwell, please contact us for advice or go immediately to your nearest Accident & Emergency.

Further information leaflets on miscarriage or ectopic pregnancy can be found here. https://www.chelwest.nhs.uk/services/womens-health-services/early-pregnancy-assessment-unit-epau

Patient Advice & Liaison Service (PALS) – Complements or complaints

If you have concerns or wish to give feedback about services, your care or treatment, you can contact the PALS office or you can complete a feedback form on our website www.chelwest.nhs.uk/pals. We value your opinion and invite you to provide us with feedback.

C&W: 020 3315 6727; cwpals@chelwest.nhs.uk

WMUH: 020 8321 6261; wmpals@chelwest.nhs.uk

Useful contacts

  • The Ectopic Pregnancy Trust
    • Tel: 020 7733 2653
    • Website: www.ectopic.org.uk
  • The Miscarriage Association
    • Tel: 019 2420 0799
    • Website: www.miscarriageassociation.org.uk
  • Crossways (Hounslow only) Listening Service
    • Tel: 020 8892 8483
    • Website: https://www.crosswaypregnancy.org.uk
  • Cradle Charity
    • Tel: 0333 443 4630
    • Website: https://cradlecharity.org
  • The Elizabeth Suite, Chelsea and Westminster Hospital (Early Pregnancy and Acute Gynaecology Unit)
    • Tel: 020 3315 5073 (admin queries only 9-12pm & 2-4pm Mon-Fri).
    • Tel: 020 3315 5070 (clinical queries only 12-2pm Mon-Fri)
  • West Middlesex University Hospital (Early Pregnancy Unit)
    • Tel: 020 8321 (6070) or (6506), 07920 020800