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First-trimester obstetric ultrasound

First-trimester obstetric ultrasound (also called dating ultrasound) is used to more accurately determine the fetus’ gestational age (number of weeks of pregnancy). The ultrasound is done between the seventh and ninth week of gestation. This procedure can also confirm the number of fetuses, the death of a fetus or an ectopic pregnancy.

Other examination available: Obstetric and nuchal ultrasound

Preparing for the examination

To properly prepare for your first-trimester obstetric ultrasound, it is important to drink two 8-ounce glasses of water (500 mL) one hour before the examination and not urinate.

A medical prescription is required to perform this examination.

The costs of this examination are covered by the Régie de l'assurance maladie du Québec (RAMQ).

If your healthcare professional has prescribed this examination or if you have any questions, contact us at 1 833 590-2715.