What should you know about nuchal scan dates?

The scan uses ultrasound to measure the fluid space at the back of the baby's neck and to assess development alongside the pregnancy dates. Your clinician may combine this finding with other screening information; it is a screening appointment, not a diagnosis. The date is based on gestational age, which is counted from the first day of the last menstrual period or adjusted after an earlier dating assessment.

Check the appointment date against the gestational age your maternity team has recorded. Follow the clinic's instructions about bladder filling, bring your pregnancy notes, and allow time for questions. If your dates are uncertain, cycles are irregular, or an earlier scan changed the estimated due date, tell the team before the appointment so they can advise whether the timing remains suitable.

Contact your maternity team promptly if bleeding, severe abdominal pain, fluid leakage, fainting, or marked dizziness occurs, rather than waiting for the scan. A missed or unsuitable appointment does not by itself indicate a problem; call the clinic to discuss another date or an alternative screening plan.

Ask which gestational age is recorded, whether the scan is part of combined screening, what happens if the timing changes, and when you will receive the result. You can also ask who will explain any finding that needs follow-up.