Fasting for a glucose test in pregnancy

Pregnancy glucose testing checks how your body handles glucose. Some screening appointments use a blood sample without fasting, while a longer glucose tolerance test may require fasting and repeat samples after a glucose drink. The instructions can differ, so do not assume that advice for one test applies to another.

Ask whether plain water is allowed, when to stop food and drinks, and whether usual medicines or supplements should be taken. Do not change prescribed treatment without instructions. Tell the team if you feel faint, vomit during the test or cannot complete the preparation.

Read the appointment instructions and check the test name. If fasting is required, plan an evening meal that fits the advice, avoid unapproved food or drinks during the fasting period, and bring a snack for after the final sample. Wear comfortable clothing and allow enough time for the appointment.

Keep taking medicines only as directed by your maternity or testing team. If you have diabetes, nausea, a history of fainting or a condition that makes fasting difficult, contact the clinic before the appointment so an individual plan can be considered.

Tell the testing staff immediately if you become shaky, sweaty, confused, very weak, dizzy or unwell during preparation or sampling. Seek urgent help for fainting, severe breathlessness, chest pain or a severe allergic reaction. Contact your maternity team if vomiting or illness prevents you from eating, drinking or attending safely.

Which glucose test am I having? Do I need to fast, and for how long? May I drink plain water? Should I take my morning medicines? What happens if I vomit or cannot fast? When and how will results be explained?