How Early Can An Ultrasound Scan Detect Pregnancy

Eventually you are called through. It might be ten minutes, it might be three quarters of an hour, but it'll certainly be long enough for you both to catch at least one of the airborne viruses that breed in the hospital's air-conditioning system. In a small darkened room, the ultrasound operator is waiting with her tube of jelly. 'Lie down here,' she says to your partner. 'Sit down there,' she says to you. There is something of the ritual dance in all this. Your partner lies on the couch. She pulls up her top to reveal the bump. You gasp involuntarily. You haven't seen her show it in public before. 
 

How Early Can An Ultrasound Scan Detect Pregnancy

The ultrasound operator starts squeezing jelly all over the abdomen, then picks up her transducer, a hand-held device that measures high-frequency sound waves bouncing off the womb and the baby's body. It is wired up to a computer monitor which, gadget fans will be disappointed to learn, is only in black-and-white. (Three-dimensional ultrasound is on the way, but as I write it is still too expensive for routine use in NHS hospitals.) 

The ultrasound operator passes the transducer over the abdomen. Ping! Up there on the screen is a baby. Well, not exactly a baby, but a few squiggly lines that might conceivably be a baby if you had the visual imagination of Salvador Dali. There, says the ultrasound operator. If you look carefully you can see its heart beating. And there's its head, and its spine and its little feet and hands ...

'Wow!' you say. 'Isn't that incredible?'

Hmm, you think. Is that all?
 
After the scan is over the Ultrasound operator may offer you a picture. You say yes, because everyone does. It is printed out for you. You express amazement and wonder and awe at this extraordinary technology, which has been around since World War Two. Slightly more advanced technology would print out a picture of a baby that looked like a baby. This looks like the photocopy of a photocopy of an artist's impression of a stoat.

Most parents-to-be will show this photo to friends, relatives and anyone who can't run away quick enough. Other than proving that the baby exists, an ultrasound photo only has one important function: to bring parents-to-be down to earth. Just as you didn't want to know when other people tried to show you their ultrasound photos, so no one else wants to know when you try and show them yours. File it away and forget about it, at least until the child is 16 and can be embarrassed in front of its friends.

This is all flim-flam, anyway. The ultrasound photo, the warm feeling of seeing your progeny's heart beat, the sneaky glances to try and work out whether it has a willy or not, are all just distractions from the main business at hand. The ultrasound, like all other scans and tests, is looking for abnormalities.

All sorts of things can go wrong in pregnancy. Many can be identified early. The latest new test as I write is the nuchal scan, which you can have done at around ten or eleven weeks (i.e. just before the first main ultrasound scan). This measures the thickness of something called the nuchal pad in the baby's neck. If this pad is thicker than it should be, then there is a higher risk of chromosomal defect, which could mean Down's syndrome. 

If that's the case, you move on to the next test, the amniocentesis, which comes at around 15 weeks. For this, they withdraw a sample of the amniotic fluid that surrounds the foetus in the womb. They don't touch the baby, but the test does carry around a 1 in 200 risk of miscarriage. That's how risks become quantified in this game - 1 in 200, 1 in 100, 1 in 50, 1 in 10. As you go through each test, so the probabilities seem to grow, and you stop sleeping at night. To find out more, you can check out How Early Can An Ultrasound Scan Detect Pregnancy.