How long does a growth scan take to work for gestational diabetes?

Gestational diabetes can affect pregnancy monitoring, so ultrasound may be used to estimate the baby's size and check amniotic fluid. Depending on the appointment, the clinician may also assess movement or blood flow. The scan is an assessment rather than a treatment: it cannot lower blood glucose or change fetal growth immediately. Your team combines the scan with glucose readings, symptoms, blood pressure, pregnancy dates, and previous measurements before deciding what happens next.

Attend the appointment and bring your glucose log if your clinic asks for it. Continue the food, activity, medicines, and glucose-monitoring plan prescribed for you. Ask when the measurements will be explained and whether another scan or review is needed. If the scan suggests a change in growth or fluid, your team may adjust monitoring or discuss birth planning; do not make those changes without their advice. Learn more on the [Growth Scan](/treatments/pregnancy-and-birth-care/growth-scan/) page.

Call promptly about reduced fetal movement, repeated high glucose readings despite following your plan, vomiting that prevents food or fluids, or symptoms of possible high blood pressure such as severe headache, vision changes, or sudden swelling. Seek urgent care for heavy bleeding, leaking fluid, severe abdominal pain, fainting, or difficulty breathing. A planned scan should not delay assessment of a new warning sign.

Ask what the scan will assess, how glucose control affects the monitoring schedule, when the measurements will be reviewed, whether fluid or blood flow will be checked, and what would change the birth plan.