Advanced 2D Scanning & Doppler in Pregnancy

In addition to the 4D images of the fetus, we will also have a detailed look at the internal anatomy of the baby with advanced 2D scanning to check for abnormalities and assess fetal growth and well-being. The same probe that takes 4D images can be used to provide advanced 2D images and blood flow measurement (Doppler). Additional important information that will be
provided at the various stages of pregnancy is summarised below.

11-14 weeks

Measuring the fetus from 'top to bottom' (crown-rump length (CRL)) will provide an accurate assessment of the gestational age and will provide an estimated date of delivery.

In addition we will carry out a screening for Down syndrome by:

Combining the nuchal scan and the blood test, we will give an individual risk assessment (likelihood ratio) for your risk of having a Down Syndrome baby. We can compare your 'starting' risk, based on your age, with the 'new' risk, which will help you decide whether you want an invasive test such as CVS or Amniocentesis. If the risk of Down's is 1:250 or greater, an invasive test is advised.

The combination of these should give an 85% detection rate for Down Syndrome. Other recent markers for Down Syndrome, such as nasal bone identification and blood flow in the Ductus Venosus, may also be performed depending on the particular clinical circumstances.

18-22 weeks

As this stage, a detailed scan is performed which will detect the large majority of serious fetal anatomical abnormalities. Detailed scanning of the baby's brain, spine, heart, diaphragm, kidneys, bladder, genitalia, limbs, fingers & toes can be seen in some detail with ultrasound.

Also at this time, blood flow in the uterine arteries is measured using Doppler ultrasound. This can predict whether the placenta will function normally or (if blood flow is impaired) whether the baby's growth will be affected or high blood pressure will develop in the mother (pre-eclampsia).

In women at risk of premature labour, the length of the cervix can be measured using transvaginal ultrasound (an internal scan): a short cervix indicates an increased risk of early delivery.

Scan 26 weeks onwards

An assessment of baby's growth and anatomy will be performed at the time of the 4D scan. Measurements of the fetal head, body and upper leg (femur) will be plotted on a graph to show the rate of growth of the baby. Blood flow in the baby's Umbilical Cord and mother's Uterine Arteries will indicate if the placenta is functioning normally. If placental blood flow is normal then an estimated prediction of the likely birth weight can be given.