Understanding Your Scan Results: Complete Guide
Coming away from an early scan with a printout full of abbreviations and jargon can feel more confusing than reassuring. This guide translates the most common terms you'll see on a pregnancy scan report into plain English, so you know what you're looking at.
Common abbreviations explained
Sonographers use standard shorthand on scan reports. Here's what the most frequent ones mean:
- GS — gestational sac, the fluid-filled structure that contains your developing pregnancy and is usually the first thing visible on a very early scan.
- YS — yolk sac, a small round structure inside the gestational sac that provides early nourishment before the placenta takes over.
- CRL — crown-rump length, the measurement from the top of baby's head to the bottom of their bottom, used to estimate gestational age and due date in the first trimester.
- FH or FHR — fetal heart or fetal heart rate, confirming a heartbeat has been seen and, where recorded, how many beats per minute.
- NT — nuchal translucency, a measurement of fluid at the back of baby's neck taken around 11 to 14 weeks as part of chromosomal screening.
- BPD, HC, AC, FL — biparietal diameter, head circumference, abdominal circumference and femur length, all growth measurements typically taken from around the 20-week anomaly scan onwards.
- EFW — estimated fetal weight, calculated from the growth measurements above and usually only recorded later in pregnancy.
What "reassuring" phrases mean
Certain standard phrases appear on almost every normal early scan report:
- "Single live intrauterine pregnancy" — this is good news. It confirms one baby (not a multiple pregnancy), a visible heartbeat ("live"), and that the pregnancy is correctly located in the uterus rather than outside it (ruling out an ectopic pregnancy).
- "Consistent with dates" — the measurements match what would be expected for the due date you were given, based on your last period or an earlier scan.
- "No obvious structural abnormality" — used at the anomaly scan to mean nothing concerning was seen in the areas checked, though it is not a guarantee of a completely healthy baby, as scans cannot detect every condition.
When a result needs more explanation
Sometimes a report includes a measurement or note that isn't immediately clear, or the sonographer mentions something during the scan that you don't fully understand. It's always reasonable to ask them, or your midwife afterwards, to explain any term in plain language before you leave. If a scan raises a genuine concern — such as a measurement outside the expected range, or uncertainty about dating — you should be offered a follow-up scan or referral to a specialist rather than being left with an unclear result.
Getting a copy of your results
You're entitled to see your own maternity notes and scan images, and most units will give you a printed report and a still image on the day. If you want your results explained again later, contact your midwife or the antenatal clinic — you don't need to wait for your next scheduled appointment if something is worrying you.
Frequently Asked Questions
What does "single live intrauterine pregnancy" mean on my scan report?
This phrase is good news. It confirms three things: there is one baby rather than twins or more, a heartbeat has been seen ("live"), and the pregnancy is developing in the correct place inside the uterus. Seeing this wording on your report generally means everything looks as expected at that stage.
What does CRL mean and why does it matter?
CRL stands for crown-rump length — the measurement from the top of your baby's head to their bottom, taken during early scans. It's the main way sonographers estimate gestational age and calculate your due date in the first trimester, because it's a very reliable growth marker before around 13 weeks.
Should I be worried if I don't understand something on my scan report?
Not necessarily — scan reports are written for clinical staff and often include shorthand that isn't obvious to anyone outside healthcare. If anything on your report is unclear or concerning, ask the sonographer before you leave the appointment, or contact your midwife afterwards. They would rather explain a term than have you worry unnecessarily.
This article is for informational purposes only and does not constitute medical advice — always ask your sonographer or midwife to explain your own results.
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