What to expect at an eight-week dating scan

The scan may show the gestational sac, embryo and cardiac activity, depending on the true stage of pregnancy and image quality. Measurements can refine the estimated due date when menstrual dates are uncertain. An unexpected finding does not always provide an immediate diagnosis; sometimes the pregnancy is earlier than assumed and a follow-up scan is needed.

Ultrasound may be performed across the abdomen or with a slim vaginal probe. A vaginal scan often gives a clearer view this early and is done with consent. The clinician checks that the pregnancy is inside the uterus, looks for the number of embryos and measures the embryo from end to end to estimate gestational age.

If dates, measurements and visible development do not align, the clinician considers cycle timing and whether another scan after an interval would clarify progression. The dating scan is distinct from later screening appointments, including a nuchal translucency scan.

Read the clinic instructions because an abdominal scan may require a comfortably full bladder, whereas you will usually empty it before a vaginal scan. Bring the date of your last menstrual period, typical cycle length and details of fertility treatment or prior scans. Tell the clinician about bleeding, pain and previous ectopic pregnancy before scanning begins.

Before leaving, confirm the estimated due date, whether the location and development were clearly seen, and whether follow-up is required. If the findings are uncertain, ask when reassessment is appropriate and whom to contact if symptoms develop meanwhile.

Seek prompt medical assessment for vaginal bleeding with worsening cramps, heavy bleeding, severe abdominal pain, one-sided pelvic pain, shoulder-tip pain, marked dizziness, fainting, fever or feeling very unwell. Call emergency services if you collapse. Do not wait for a routine dating-scan appointment when these warning symptoms occur.

You may want to ask which measurement was used for dating, whether the due date replaces the menstrual estimate, and what was seen regarding pregnancy location and cardiac activity. If more than one embryo is present, ask what additional monitoring may be offered.