A self-help guide for managing your blood glucose at home with insulin.
Why do I need insulin?
- Pregnancy hormones can increase your blood glucose.
- High blood glucose is associated with large babies, increasing the risk to both mum and baby.
- Insulin will help to lower you blood glucose to normal levels.
Why do I need to change my insulin dose?
Every woman needs different amounts of insulin, and as your pregnancy progresses you will need more insulin. It is important to increase the dose to keep your blood glucose within target.
Low blood glucose
If your blood glucose is 3.5 or below, with symptoms (dizziness, shaking, sweating, or irritability):
- Treat it immediately with a carton of fruit juice or 4 dextrose tablets and reduce your insulin by 4 units that night.
- Call us to discuss your insulin dose after you have low blood glucose.
- Monday to Friday, 08:00 to 16:30 call the diabetes midwives on 0117 414 1072.
- Outside of these hours call the Maternity Assessment Unit on 0117 414 6906.
The flow chart below shows when to check your blood glucose and what to do if it is below 5. Please ask us if you need help understanding this. We will tell you how many units of insulin to start with.
Flow chart written steps
Steps
- Start taking insulin every night. We will tell you how much to start with.
- Check your fasting blood glucose in the morning.
- If below 5 go to step 3.
- If above 5 go to step 4.
- Continue with current insulin dose. Go to step 2.
- Increase insulin by 4 units at night. Go to step 2.
Top tips
- It is common for you insulin dose to increase over time.
- There is no upper limit to insulin dose.
- You will be able to stop the insulin after birth.
- The diabetes antenatal team will be here to support you throughout your pregnancy.
- Insulin is safe to inject in pregnancy.
© North Bristol NHS Trust. This edition published December 2025. Review due December 2028. NBT003831.
Support your local hospital charity
See the impact we make across our hospitals and how you can be a part of it.