Low fasting blood sugar in pregnancy: what to know

Blood glucose can fall after a long overnight fast, especially when nausea or vomiting makes eating difficult. Symptoms of low blood sugar may include dizziness, sweating, shakiness, irritability, nausea, blurred thinking, or generalised weakness. People using insulin or certain diabetes medicines need particular care because treatment can lower glucose.

One reading does not explain the cause by itself. Your maternity clinician may ask about food intake, vomiting, diabetes history, medicines, timing, and symptoms, then decide whether repeat testing or diabetes review is needed. Do not change prescribed medicine without advice.

If you are awake and able to swallow, follow the action plan given by your maternity or diabetes team. This may involve a quick source of carbohydrate followed by a balanced snack or meal, with rechecking when instructed. Keep glucose supplies and a snack available, and avoid skipping meals when possible.

Contact your maternity team about repeated low readings, ongoing vomiting, difficulty keeping food down, or symptoms that return. Record the reading, time, food, medicines, and symptoms. Pregnancy changes nutrition and medicine needs, so personalised advice matters.

Call emergency services for fainting, seizure, severe confusion, inability to swallow safely, or loss of consciousness. Seek urgent maternity advice for persistent dizziness, repeated vomiting, marked weakness, or low readings that do not improve according to your care plan. Do not give food or drink to someone who is unconscious.

What range is expected for my test and how should I respond to a low reading? Could nausea, fasting, insulin, or another medicine be contributing? Should I change meal timing? When should I recheck glucose or attend hospital? What should my support person do if I become confused?