What is the dating scan, my first pregnancy ultrasound?
In short
- The dating scan uses sound waves (not X-rays) to check how many weeks pregnant you are.
- It's usually done at 11 to 14 weeks, in the UK often with the NT screening scan.
- It also checks if it's one baby or more, and where the pregnancy sits.
- Your sonographer shows you the images. Your doctor follows up on anything unclear.
What happens
- A sonographer applies gel to your abdomen (or uses an internal probe, if it's very early) and moves a handheld scanner over the area.
- Images of your baby appear on a screen, and measurements are taken to estimate gestational age.
- The scan usually takes 15 to 30 minutes, and you can normally see the screen and ask questions.
Baby's sex is never revealed
It is illegal in India for anyone -- including your sonographer -- to reveal, or help you find out, the sex of your baby before birth. This is the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act, 1994.
Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act, 1994. Read the Act (India Code).
The details: numbers and where they differ
In the source's own words
during your 12-week scan (dating scan), when you're between 11 and 14 weeks pregnant
NHS (UK), Pregnancy ultrasound scans. Quoted verbatim.
The numbers
| Measure | Value | Source |
|---|---|---|
| Dating scan window (pregnant women (NHS, UK)) | 11–14 weeks gestation | NHS (UK) |
| Standard (routine) ultrasound exam window (pregnant women (ACOG, US)) | 18–22 weeks gestation | American College of Obstetricians and Gynecologists (ACOG) |
When to call your doctor
- If you haven't been offered a dating scan and aren't sure when yours is scheduled.
- If your sonographer or doctor flags anything on the scan that needs a follow-up appointment.
Discuss your results with your doctor: this page reports what these sources say, not advice for your situation.
Sources
- NHS (UK), Pregnancy ultrasound scans. Quoted verbatim. OGL-style NHS content, free reuse with attribution.
- American College of Obstetricians and Gynecologists (ACOG), Ultrasound Exams (Patient FAQ). Named as the guideline this section describes; its text and tables are not reproduced here (All rights reserved (cite only)). Says one standard ultrasound exam is usual, typically at 18 to 22 weeks; a first-trimester scan is not considered standard everywhere because it's too early to see many organs in detail.
- World Health Organization (WHO), Maternal and fetal assessment update: imaging ultrasound before 24 weeks of pregnancy (2022), 2022. Paraphrased in our own words. CC BY-NC-SA 3.0 IGO (WHO), non-commercial.
Sources checked 2026-09-26. How we source and check every page.
Educational summary of named sources, not medical advice.