What is a Pregnancy Viability Scan?


Do you know what a Pregnancy Viability Scan is ? You’ve just found out you’re pregnant and trying to wade through all the scans and tests, this is especially confusing if you have never been pregnant before.  The NHS does not offer viability scans. It is likely that unless you have bleeding or other issues, you will not have a scan until you are around 12 weeks. By having a private scan performed, this does not affect your NHS entitlement.

Pregnancy Viability Scan

Also known as Early Pregnancy Scan or Dating Scan. Performed from 6-10 weeks.  If you are unsure on how to date your pregnancy click on this link: Interpreting Pregnancy Test Results

This will help you work out when to book your Pregnancy Viability Scan, if you have the scan too soon, it may be that nothing can be seen. 5+ weeks is too soon to have a scan, there will be nothing to see and it could prove upsetting to not hear a heartbeat or see a gestational sac.

Why Have A Pregnancy Viability Scan

  • Reassurance – If you have previously had a miscarriage, having a viability scan can reassure you that this pregnancy is starting out well.  At 6 weeks gestation a heartbeat can be seen and heard and this reduces the likelihood of a miscarriage down to 10%. At 8 weeks gestation, the risk of a miscarriage when a heartbeat is present is reduced to 2%. This is very reassuring. But to have a scan at 6 weeks, your dating must be accurate. If there is no heartbeat, this will be very upsetting but it could simply be that you are a little early and another week would make all the difference.
  • Dating – If you have an irregular cycle, the actual date of conception might not be easy to calculate and the viability scan will date your pregnancy, giving you an accurate delivery date.
  • Number of Embryos – Most mums-to-be expect to have one baby at a time, but sometimes nature takes a turn and you may have two or even three gestational sacs.  If you have twins or triplets, the care you will need during your pregnancy will change, to ensure that all babies develop normally.
  • Position of the Gestation Sac – If you have previously had an ectopic pregnancy, this is important to check to ensure that the pregnancy is developing in the uterus and not in the fallopian tube as this is a medical emergency and the pregnancy must be removed before the fallopian tube ruptures.
  • Gestational Size – If you know that your dates are correct, it is reassuring to check the gestational size is within normal limits. This gives your obstetrician and midwife information about the early development of your pregnancy. The fetal measurement is taken from the top of the baby’s head (the crown) to the baby’s bottom (the rump).  Your Obstetrician and Midwife will talk about the crown/rump length  – CRL
  • Bleeding – This is a worrying sign in early pregnancy but may not mean that anything is wrong.  A viability scan, if bleeding should occur is important, to check that the pregnancy is unaffected and reassure that the bleeding will settle and the pregnancy is ongoing.
  • Pain – Pain is not usually a feature of early pregnancy, but it does not necessarily mean there is anything wrong.  However pain in early pregnancy should be investigated, because it could be a symptom of an ectopic pregnancy and this is a medical emergency.  The pregnancy cannot continue if it is not in the body of the uterus.

The Scan

The ultrasound scan is performed through your tummy,  is painless and non harmful for the baby.  It is carried out by Mr Penman who is a consultant fetal medicine specialist. Many other scanning establishments do not have a consultant doing the scan but a monographer.  Mr Penman is trained in Fetal Medicine. He looks at  various features and takes measurements which are documented.  He will show you the heartbeat on the monitor and print out various 2D images.  Mr Penman will explain everything to you as he performs the can and also give you a report for your obstetrician and midwife.  The scan takes around 10-15 minutes.

If you have a BMI over 30, the images on the monitor and printouts will not be as clear because the scan sends sound waves out that map the shape and size of your pregnancy and has to go through more tissue to get to the pregnancy, so please bear this in mind when you attend for the scan.

If you would like to book a Pregnancy Viability Scan, click on the ‘Book A Baby Scan’ Button to the right of this article or click on the link to go to the Pregnancy Booking Form. You can fill the form in and submit it online, a booking clerk will contact you within 24 hours to make a suitable appointment or you can ring the hospital department directly.


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