What should you know about dating scan time?

The appointment uses ultrasound to look at the pregnancy, its location and the developing embryo. Measurements can provide an estimate of how far the pregnancy has progressed when the date of the last menstrual period is uncertain or cycles are irregular. The scan may also assess whether a heartbeat is visible at that stage. The exact timing can vary with local maternity pathways, symptoms, previous pregnancy history and the information your clinician needs.

A dating scan is different from a nuchal translucency scan, which is a later screening examination. Your care team can explain which scan is being offered and why.

Take any referral details and note the first day of your last period if you know it. Bring questions about the scan and tell the sonographer about previous pregnancy dates or fertility treatment, because these details can affect how the findings are interpreted. Follow the appointment instructions about drinking water or having a full bladder; requirements differ according to the type of ultrasound and the service.

During the visit, you may have an abdominal scan and, when an earlier or clearer view is needed, a transvaginal scan. Ask for an explanation of what was seen and when you will receive the report.

Contact your maternity service promptly for vaginal bleeding, one-sided or severe abdominal pain, shoulder-tip pain, fainting, dizziness or feeling very unwell. These symptoms need medical assessment regardless of when your scan is booked. If you are waiting for an appointment and symptoms change, do not wait for the scan to address them.

Ask: When should my scan take place? Will it be abdominal, transvaginal or either depending on the view? What information will the measurements provide? When and how will I receive the result? What symptoms should prompt urgent contact?