Ultrasound scan

Ultrasound scan is a procedure that uses high frequency sounds to form a picture of the inside body on a monitor. There is no radiation involves as this is only a sound wave. This is a high frequency sound wave that human ear can’t hear.

Technique: A small transducer (probe) is used to generate sound waves on the surface of the body. These sound waves are reflected back by internal organs and they are again received by the same transducer. These are then processed by a computer to produce an image of the internal organ.

Types of ultrasounds:

External: Probe is placed on the surface of the body to generate images
Internal: Probe is placed in the vagina to generate image of the pelvic organs
Internal ultrasound scan uses high frequency probe and closer to the pelvic structures (uterus, ovaries, cervix and fallopian tubes). So, it produces a much clear image of internal organs than external scan of the pelvis.

How do I prepare for the scan?

There is no special preparation needed for the ultrasound scan. However, it is advisable to wear a loose fitting, comfortable clothing as you may have to remove part of the clothing or move the clothing for probe placement and scanning. If you are having an external scan you should have full bladder. So, drink enough water and hold your urine. This will help with the transmission of sound waves and better visualisation of pelvic structures. You do not need full bladder for internal scan. In fact, we ask you to empty the bladder before the scan. Sometimes, you may need both internal and external scans. If this is the case, we will do the external scan 1st with full bladder and then internal scan after emptying the bladder. If in doubt, please ask nursing staff on arrival.

What happens during the scan?

There will be a female nurse present throughout the procedure.

External scan: You will be lying on your back on a cough. A gel is placed on the lower part of the tummy. This will help with the transmission of sound waves. Sonographer / Doctor moves the probe over the lower part of the tummy and stores images on the screen. You will be shown the images as we scan. As pelvic organs are situated within the pelvis, you need a full bladder to perform external scan.

Internal scan: You need to empty the bladder first. You will be lying on your back on a couch with a small wedge is placed under your back to slightly elevate your pelvis. Probe is covered with a cover (for infection prevention) and a gel placed on this. Probe is slowly introduced and placed in the vagina. If you prefer you can introduce the probe yourself.Gentle rotational and sideways movements are made on the probe to capture the image on the screen. You can follow the pictures on the scan as we scan.

After the scan: You will be able to go home or to work straight away. There is no sedation involves and you will not feel any difference after the scan. Internal or external scans are not painful but some ladies may feel discomfort during the scanning due to pressure of the probe.

I am pregnant, what scan do I need?

This depends on the gestation and the reason for the scan. In general, I recommend internal scan for early pregnancy patients till 13 weeks. During this time uterus and the baby will be in the pelvis and external scan may not show a clear image of the baby and other pelvic structures. Most of the early pregnancy complications are diagnosed during this time, including ectopic pregnancy, threatened miscarriage, miscarriage, bleeding in the womb, ovarian cysts, etc. Therefore, it is important we visualise pelvis clearly and only internal scan will do this during this time. So, if you have any symptoms like abdominal pain, bleeding, etc an internal scan is strongly recommended. If you need a scan for dating, reassurance or a 2nd scan following a previous normal internal scan, an external scan is reasonable as long as you are more than 10 weeks pregnant.

How do you perform 3D Ultrasound scan?

Procedure is the same as an internal scan. Same probe or a slightly bulky probe is used. It is the technique of scanning and post scanning processing and editing of the image that makes 3D scanning is different from normal scanning. 3D scanning is not real time. You can view the images straight away after scanning but not as we scan.

Are there any risks?

There are no known risks associated with ultrasound scan as it involves only sound waves. The cover that covers the probe is usually made of latex. So, if you are allergic to latex, it is important you inform us before the scan, so that we can use a latex free probe cover.

Are there any risks to my baby with ultrasound scan?

There are no known risks to the baby even at very early gestations with medical ultrasound scanning as long as the recommended settings and duration are followed.

Does internal scan cause bleeding or miscarriage?

Internal scan probe is placed in the vagina. It never goes beyond vagina. Bleeding during miscarriage happens with bleeding in the uterus / gestational sac. Vaginal scan never causes bleeding or miscarriage in pregnancy. But if you are about to miscarry or bleed, internal scan will not stop this happening either, it will only help in the diagnosis. It is important that we diagnose your condition properly and therefore internal scan is important during early pregnancy.

Can internal scan be performed while I am bleeding?

Yes, It is safe to do internal scan even if you have bleeding in pregnancy. In fact, it is important that we do internal scan to diagnose the reason for the bleeding

Is there any risk of infection with internal scan?

No. After each scan probe is cleaned with an antiseptic solution and covered with a disposable sterile probe cover. This prevents any transmission of infection.

Further information:

https://www.nhs.uk/conditions/ultrasound-scan/