Pregnancy Ultrasound (first trimester)

What it is

In the first trimester the embryo is a few millimetres to a few centimetres long, so the scan is not yet about examining organs in detail. It is about establishing the basic facts of the pregnancy. Is there a pregnancy visible at all, and is it in the uterus rather than somewhere it should not be. Is there cardiac activity. How many are there. And how big is the embryo, which is the most reliable way to date a pregnancy, because early growth follows a tight enough schedule that a measurement translates into a due date more accurately than it ever will again. Sound waves do the work; nothing is injected and no radiation is used.

Why it is done

• To confirm the pregnancy is inside the uterus, which is the question behind most early scans ordered urgently
• To establish dates and a due date from measurement of the embryo
• To check for cardiac activity
• To find out how many embryos there are
• To investigate bleeding or pain in early pregnancy
• To look at the ovaries and uterus at the same time, since a cyst or a fibroid found now affects what is expected later

What to expect

Two approaches are used and either may happen at this stage. Scanning through the abdomen needs a full bladder to lift the bowel out of the way, so there is often an instruction to drink water beforehand and hold it. The transvaginal approach uses a slim probe placed into the vagina, which sits much closer to the uterus and sees far more in early pregnancy; for this the bladder should be empty. It is usually described as pressure rather than pain. The sonographer may be quiet during the scan while taking measurements, which is normal and not a sign of a finding. Some of what this scan can measure feeds into separate screening tests offered around the same weeks; those are ordered and billed on their own.

Questions worth asking

• Many obstetric practices bill pregnancy care as one global package. Ask whether this scan is inside that package or billed on its own.
• If more than one embryo is seen, ask whether an additional charge applies for each one beyond the first.
• Ask whether the charge is split into a technical part for the scan and a professional part for the doctor reading it, and whether both are in network.
• If the scan is repeated a week or two later because it was too early to see what was needed, is the second visit billed at the full price again?
• If it is done in a hospital rather than in the obstetrician's office, ask what facility fee is attached.