Internal Ultrasound

The ultrasound scan is a staple part of antenatal care across the globe. Ultrasound technology allows for the safe and effective imaging of a developing embryo/foetus from the beginning to the end of a pregnancy, allowing for your peace of mind and for a close watch to be kept on your health and that of your unborn baby. It comes as a surprise to many people that there is in fact more than one type of ultrasound that is used throughout the length of a pregnancy, albeit often less often than the traditional ‘external’ ultrasound. This article explores the use of one of these types of ultrasound, the internal ultrasound.

What is an internal ultrasound?

Also referred to as a transvaginal ultrasound, an internal ultrasound relies on the same basic principle as other ultrasound technology. Sound waves of a particular frequency (more widely known as ultrasound) are produced by a device called a transducer or ultrasound probe, these are then reflected off various surfaces across from the probe, returning at different times and angles. A computer linked to this transducer is responsible for interpreting this complex mess of information, and produces what we see as an image of the area being scanned.

An internal ultrasound is unique in that rather than an external probe which is placed on top of a pregnant belly, the device needs to be inserted through the female reproductive tract (into the vagina) to successfully image internal organs and other structures. This can be uncomfortable, which is why internal ultrasound is not used as much as its exterior equivalent.

When is an internal ultrasound used?

Internal ultrasound scans are not a routine part of antenatal care as they can be unpleasant, while external ultrasound techniques are quick and easy to perform and provide your healthcare professionals with the information they need. However there are times when the more detailed images of particular organs that an internal ultrasound can provide are needed.

If your doctor or midwife wants to take a detailed look at the uterus (womb), ovaries, vagina, or cervix, then the internal ultrasound is used as it can provide a much higher resolution image of these organs. This test will most likely be requested if something unusual is detected during a physical exam, for instance, an unusual growth like a cyst. Unusual bleeding from the vagina is also a common cause for an internal ultrasound scan, as are unexplained pelvic pains and ectopic pregnancies (where an embryo implants anywhere that isn’t the womb and develops at that location).

Are internal ultrasound scans safe?

Internal ultrasound scans are known to be perfectly safe, and are commonly used during antenatal care across the world. As sound waves are used rather than radiation, you and your foetus are spared any potential damaging effects that can sometimes occur as a consequence of exposure to ionising radiation.

Are internal ultrasound scans painful?

While the idea of having a probe inserted into the vaginal tract is certainly not a pleasant one, you can rest assured that the internal ultrasound procedure is a painless, if uncomfortable one. Painkillers are sometimes offered if requested, but generally speaking the test is performed quickly and painlessly.

Where can I get internal ultrasound scans from?

In the UK you can receive this test under both the NHS and private care as it is a fairly routine part of antenatal care. While exterior ultrasound scans are used more often (as mentioned previously), the internal scan is still used when deemed appropriate.

The internal ultrasound is one of many superb tools used during antenatal care to make sure that everything is proceeding healthily and normally. While not the most common form of ultrasound used at present, it is nonetheless used relatively often to great effect.