In addition to the monitoring provided by your midwife or doctor, ultrasound scans can supply more information about your baby’s growth and development.
what is it?
An ultrasound scan is a painless test that sends high-frequency sound waves through your uterus (womb). A warm gel is spread over your abdomen and a sonographer presses a hand-held ‘transducer’ firmly against the skin, moving it until the desired images are captured.
The sound waves pass through fluid and soft tissues, but bounce off your baby as an echo, which is turned into an image on a screen.
It’s a very commonly-used test. As it employs sound waves and not radiation, it’s thought to be harmless, and research hasn’t linked it to any complications.
An ultrasound scan does generate some heat, but your baby is moving, and the amniotic fluid helps to spread the heat. As antenatal scans produce less than 1ºC, they are fine for you and your baby.
3D and 4D scans are just as safe as 2D scans, because the image is made up of sections of 2D images converted into a picture. The sound wave intensity is the same as it is for 2D scanning.
nuchal translucency ultrasound scan
It’s recommended that all pregnant women have a scan in the first trimester to establish the due date, and to check the number of babies and the position of the placenta. This scan may also indicate chromosomal abnormalities (Down syndrome) by measuring the thickness of the layer of fluid on the back of the baby’s neck. However, you can have the scan and request that they don’t perform the Down syndrome screen.
The Ministry of Health currently funds first trimester combined screening:
- a blood test to measure a couple of proteins when you are between 9-13 weeks pregnant, and
- a Nuchal Translucency ultrasound scan at 11-14 weeks. (You may be asked to pay a surcharge for this scan.)
The results of these tests, together with information about your age and weight, determine the risk of your baby having Down Syndrome.
This scan, performed at 19-20 weeks, examines each part of your baby’s body, checking for structural or physical abnormalities. If you wish to know the gender of your baby, this scan will reveal it, unless the baby has its feet tucked up between its legs.
Getting a 3D scan means the resulting picture stands out from the page or screen and is more life-like compared with the usual flat two-dimensional image. You don’t need to wear special glasses to see it.
The scan is best done as a separate appointment, preferably between 28-32 weeks, when the baby’s features are the clearest. You won’t need a referral from your maternity carer because this is a non-medical scan and therefore not funded.
Sometimes the baby just isn’t in a good position to see the face. Also, if you really don’t want to know the baby’s gender, you might reconsider having a 3D scan, as you never know what part of the baby will be seen during the scan.
A 4D scan is just a 3D scan with an extra dimension — time. So instead of a motionless 3D image, 4D is the moving 3D picture recorded on DVD — a real-time movie of your baby, and a truly bonding experience.
You may be offered extra scans to monitor the growth and wellbeing of your baby if:
- there were complications in your previous pregnancy
- you have diabetes, high blood pressure or a BMI of over 35
- it’s a multiple pregnancy
other types of scans
- A Doppler scan checks that enough blood, carrying oxygen and nutrients, is reaching your baby. It works by concentrating a beam of sound in a small area.
- Cardiotocography is a method of continuous foetal heart rate monitoring with an electronic foetal heart monitor strapped to your abdomen. This picks up the foetal heart rate using pulsed ultrasound and electronically records it for about 15-20 minutes. This form of ultrasound can be used during pregnancy and labour to assess foetal wellbeing.
- Foetal biophysical profile: uses both continuous electronic foetal heart monitoring and ultrasound scanning to assess foetal wellbeing and placental functioning, and is usually recommended if your pregnancy continues for more than 7-10 days after your estimated due date, or if there are concerns about a baby’s growth and wellbeing at any stage during pregnancy.
- Cervical scan: If you experienced complications in a previous pregnancy, you may be advised to have a scan to measure the length of your cervix.
- A chorionicity scan is used to find out if your twins share a placenta, or have separate placentas.
hey baby, did you know …?
- The Greeks thought that mother’s milk was produced in the uterus and transported to the breast by special vessels in the body. There existed since the Middle Ages a vague awareness that breast milk provided some protection against sickness – but colostrum was considered dangerous, and women were advised not to feed the newborn baby for a few days. An older child would draw the breast milk first.
- Spoons were often used to feed infants and were known as ‘pap boats’. Expensive and elaborate versions were available to those who could afford it. The expression “born with a silver spoon in one’s mouth” probably evolved around the 16th century.
- In Europe, milk was not pasteurised until the 1890s and was avoided, particularly for infants, because people believed their child would grow up to resemble the animal.
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