What should you know about gestational diabetes mellitus risk factors?

A risk factor does not diagnose gestational diabetes, and someone without recognised risk factors can still develop it. Pregnancy hormones can reduce how effectively insulin works, so screening remains important even when a pregnancy appears low risk.

Your clinician may ask about diabetes in close relatives, a previous baby with higher birth weight, gestational diabetes in an earlier pregnancy, polycystic ovary syndrome, or glucose levels found before pregnancy. They may also consider medicines and other health conditions. Share this history early so the timing of screening can be planned.

Tell your antenatal team about previous test results, pregnancies and medicines. Attend the screening they recommend and ask how to prepare. A glucose tolerance test uses timed blood samples after a glucose drink; your team will explain whether fasting is needed and what to do if you feel unwell during the test.

If gestational diabetes is diagnosed, treatment may include meal planning, movement suited to your pregnancy, home testing and medication. These steps are based on your readings, not on a risk factor alone.

Call your maternity team if you cannot complete a planned test, have repeated glucose readings above your agreed target, or develop marked thirst, frequent urination, vomiting or unusual weakness. Seek urgent pregnancy care for heavy bleeding, severe pain, severe headache with vision changes or reduced baby movements.

Which factors apply to me? When should I be screened? Do I need an earlier or repeat glucose tolerance test? How should I prepare? What follow-up is needed if the result is normal or raised?