Dating ultrasound scan

Dating ultrasound scan: 11 to 14 weeks Gestation


The dating pregnancy scan is performed on pregnant women to detect the gestation age of the foetus. It is very useful for women who are uncertain of their last menstrual period or have irregular menstrual cycles and therefore making it difficult for their doctor to correctly estimate the gestational age and when the baby is due.

Ultrasound is very accurate in estimating the baby’s due date and the earlier the scan the better the accuracy. The most accurate time is between 11 and 14 weeks of gestation.  In general ultrasound scans performed during the first trimester are within 3 – 5 days of accuracy. After 28 weeks, the estimation of the due date can be as long as 3 weeks out.

We offer the early pregnancy scan if you are below 11 weeks pregnant.

The overall accuracy of the scan also depends on the skills of the sonographer and the ultrasound machine image quality. This why our sonographers are all NHS qualified sonographers and we are using the latest ultrasound machine.

This pregnancy scan also is known as viability scan can provide the very much needed reassurance that the pregnancy is progressing normally and there are no pregnancy complications such as an ectopic or a miscarriage.

Reasons for having a dating ultrasound scan

The most common reasons for having this obstetric scan include:

  • Irregular periods
  • Uncertain of your pregnancy dates
  • History of ectopic pregnancy
  • General reassurance

What is the purpose:

The purpose of this scan is:

  • Dating of pregnancy
  • Measuring the crown to rump length
  • Single or multiple pregnancies
  • Confirming foetal heartbeat.


What is included with this prenatal scan?

The scan includes Ultrasound Report with a 2D b/w picture


Preparation for this examination?

We need a full bladder for this scan so you need to drink 1/2lt (1 pint) of water an hour before your scan


What should I expect?

Before the private ultrasound scan, our sonographer will explain the examination procedure.

This scan is normally performed trans-abdominally. In some instances, however an internal scan (Trans-vaginal) may be required to see all the necessary detail or if your womb tilts backwards.

We will always try to scan abdominally first but if we need to do a transvaginal ultrasound scan then we will discuss this with you. To perform this baby scan, you will be asked to lie down on the examination couch and expose your lower abdomen.

A small amount of water-based gel will be applied to your skin. The gel will help the transducer to make good contact with the skin. The ultrasound transducer will be placed on the body and will be moved in different directions over the area of interest to obtain the required information/ultrasound images.

There is usually no discomfort from pressure as the transducer or probe as otherwise known,  is pressed against the area being examined. However, if scanning is performed over an area of tenderness, you may feel pressure or minor discomfort from the transducer.

Once the screening test is completed, the clear ultrasound gel will be wiped off your skin. Any portions that are not wiped off will dry quickly. The ultrasound gel does not usually stain or discolour clothing.

This examination is usually completed within 20 minutes. After an ultrasound examination, you should be able to resume your normal activities immediately.

What is the next antenatal scan following this one?

Your next scan will be a growth scan or a sexing scan.