posted 11th July 2023
Every ultrasound scan in early pregnancy aims to answer two main questions:
• Where has the pregnancy implanted?
• Is the pregnancy progressing well or not?
A Pregnancy of Unknown Location (PUL) means that we cannot confidently visualise the pregnancy with a transvaginal scan and we cannot answer the first question even though you had a positive pregnancy test.
There are 4 reasons why this may have occurred:
• A very early normal pregnancy in the uterus. This means that the pregnancy is in the correct place, just too early to visually seeing anything on a scan.
• Your pregnancy may be growing in your womb but not at the normal rate because it is not progressing well and it is going to miscarry.
• You may have already had a miscarriage.
• Ectopic pregnancy, the pregnancy is not developing inside the womb but instead developing outside the lining of the womb.
How common is this?
The national institute of health has stated the reported rate of PUL, among women attending early pregnancy units, varies between 5 and 42%.
What happens next?
• If you receive a report stating a Pregnancy of Unknown Location, the specialised Units will need to either:
o establish the pregnancy is ongoing, located correctly and progressing in the correct time frame.
Or
o that the pregnancy is not progressing, the HCG levels have fallen and you test negative on a pregnancy test.
Follow ups may take days or weeks depending on the stage of each pregnancy.