How to reduce fasting blood sugar level during pregnancy

Medically Reviewed by Michael Dansinger, MD on December 08, 2021

Gestational diabetes is a condition in which your blood sugar levels become high during pregnancy. It affects up to 10% of women who are pregnant in the U.S. each year. It affects pregnant women who haven’t ever been diagnosed with diabetes.

There are two classes of gestational diabetes. Women with class A1 can manage it through diet and exercise. Those who have class A2 need to take insulin or other medications.

Gestational diabetes goes away after you give birth. But it can affect your baby’s health, and it raises your risk of getting type 2 diabetes later in life. You can take steps so you and your baby stay healthy.

Women with gestational diabetes usually don’t have symptoms or may chalk them up to pregnancy. Most find out that they have it during a routine screening.
You may notice that:

  • You’re thirstier than usual
  • You’re hungrier and eat more than usual
  • You pee more than usual

When you eat, your pancreas releases insulin, a hormone that helps move a sugar called glucose from your blood to your cells, which use it for energy.

During pregnancy, your placenta makes hormones that cause glucose to build up in your blood. Usually, your pancreas can send out enough insulin to handle it. But if your body can’t make enough insulin or stops using insulin as it should, your blood sugar levels rise, and you get gestational diabetes.

You’re more likely to get gestational diabetes if you:

  • Were overweight before you got pregnant
  • Are African-American, Asian, Hispanic, Alaska Native, Pacific Islander, or Native American
  • Have blood sugar levels that are higher than they should be but not high enough to be diabetes (this is called prediabetes)
  • Have a family member with diabetes
  • Have had gestational diabetes before
  • Have polycystic ovary syndrome (PCOS) or another health condition linked to problems with insulin
  • Have high blood pressure, high cholesterol, heart disease, or other medical complications
  • Have given birth to a large baby (weighing more than 9 pounds)
  • Have had a miscarriage
  • Have given birth to a baby who was stillborn or had certain birth defects
  • Are older than 25

Gestational diabetes usually happens in the second half of pregnancy. Your doctor will check for it between weeks 24 and 28, or sooner if you're at high risk.

Your doctor will give you a glucose tolerance test: You’ll drink 50 grams of glucose in a sweet drink, which will raise your blood sugar. An hour later, you’ll take a blood glucose test to see how your body handled all that sugar. If the results show that your blood sugar is higher than a certain level, you’ll need a 3-hour oral glucose tolerance test, meaning you’ll get a blood glucose test 3 hours after you drink a 100-gram glucose drink. Your doctor can also test you by having you fast for 12 hours, then giving you a 75-gram glucose drink and a 2-hour blood glucose test.

If you’re at high risk but your test results are normal, your doctor might test you again later in your pregnancy to make sure you still don’t have it.

If you have gestational diabetes, you’ll need treatment as soon as possible to keep yourself and your baby healthy during your pregnancy and delivery. Your doctor will ask you to:

  • Check your blood sugar levels four or more times a day
  • Check your urine for ketones, chemicals that mean that your diabetes isn’t under control
  • Eat a healthy diet
  • Make exercise a habit

Your doctor will keep track of your weight and your baby’s development. They might give you insulin or another medicine to keep your blood sugar under control.

The American Diabetes Association recommends these targets for pregnant women who test their blood sugar:

  • Before a meal: 95 mg/dL or less
  • An hour after a meal: 140 mg/dL or less
  • Two hours after a meal: 120 mg/dL or less

Take these simple steps to stay healthy:

Eat a healthy, low-sugar diet. Talk to your doctor to be sure you’re getting the nutrition you need. Follow a meal plan made for someone with diabetes:

  • Trade sugary snacks like cookies, candy, and ice cream for natural sugars like fruits, carrots, and raisins. Add vegetables and whole grains, and watch your portion sizes.
  • Have three small meals along with two or three snacks about the same times every day.
  • Get 40% of your daily calories from carbs and 20% from protein. Most of the carbs should be complex, high-fiber carbs, with fat being between 25% and 40%.
  • Aim for 20-35 grams of fiber a day. Foods such as whole-grain breads, cereals, and pasta; brown or wild rice; oatmeal; and vegetables and fruits will help get you there.
  • Limit your total fat to less than 40% of your daily calories. Saturated fat should be less than 10% of all the calories you eat.
  • Eat a variety of foods to make sure you get enough vitamins and minerals. You may need to take a supplement to cover your bases. Ask your doctor if they think you should take one.

Exercise throughout your pregnancy. You can exercise when you have gestational diabetes as long as your doctor says it’s OK. Being active is a good way to help manage your blood sugar. Staying fit during pregnancy is also good for your posture and can curb some common problems, like backaches and fatigue.

  • Get active as soon as possible. Aim for 30 minutes of moderate activity most days of the week. Running, walking, swimming, and biking are good options.
  • Was there a workout that you were doing before you found out you were pregnant? Do you have an activity that you love? Check with your doctor to see if you can keep it up, if you should make some changes, or if it's better to try something else.
  • Exercise can lower your blood sugar. So when you work out, always have a form of quick sugar with you, such as glucose tablets or hard candy.

Get the right prenatal care: Not only can your doctor screen you for this condition; they can offer advice on food, activity, and weight loss. They can also point you to other health professionals, like nutritionists, that can help.

If you have morning sickness, eat small snacks. Nibble on crackers, cereal, or pretzels before you get out of bed. As you go through your day, have small meals often and avoid fatty, fried, and greasy foods.

If you take insulin, make sure you've got a plan to deal with low blood sugar. Throwing up can make your glucose level drop. Talk to your doctor if you're not sure what to do.

You can lower your risk before you get pregnant by:

  • Eating a healthy diet
  • Staying active
  • Losing extra weight

Your baby will probably be healthy, if you and your doctor manage your blood sugar while you have gestational diabetes.

Right after you give birth, doctors will check your newborn's blood sugar level. If it’s low, they may need to get glucose through an IV until it comes back up to normal.

Gestational diabetes raises the chance that you will have a baby who is larger than normal. It's also linked to jaundice, in which the skin looks yellowish. Jaundice generally fades quickly with treatment.

Although your child will be more likely than other kids to get type 2 diabetes later on, a healthy lifestyle (including a good diet and lots of physical activity) can cut that risk.

Because you had gestational diabetes, you have a greater chance of having type 2 diabetes. But it won’t definitely happen, and you can take action to prevent that.

Your blood sugar levels will likely return to normal about 6 weeks after childbirth. (Your doctor will check on that.) If it does, you should get follow-up tests every 3 years.

To lower your risk:

  • Try to keep your weight in a healthy range. Not sure what that is? Ask your doctor.
  • Eat a good diet that includes lots of vegetables, whole grains, fruits, and lean protein.
  • Make exercise a habit.

If you plan to have another baby, keep in mind that you are more likely to get gestational diabetes again. Ask your doctor if there are any lifestyle changes that would help you avoid that.

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If you have gestational diabetes, the chances of having problems with the pregnancy can be reduced by controlling your blood sugar (glucose) levels.

You'll also need to be more closely monitored during pregnancy and labour to check if treatment is working and for any problems.

You'll be given a testing kit that you can use to check your blood sugar (glucose) level.

This involves using a finger-pricking device and putting a drop of blood on a testing strip.

You'll be advised:

  • how to test your blood sugar level correctly
  • when and how often to test your blood sugar – you'll usually be advised to test before breakfast and 1 hour after each meal
  • what level you should be aiming for – this will be a measurement given in millimoles of glucose per litre of blood (mmol/l)
  • how to share your blood sugar levels with your care team, to help you get the right advice and treatment

If you take insulin and have problems with low blood sugar (hypoglycaemia) or your blood sugar is not stable, your care team might offer you a continuous glucose monitor (CGM).

This is a small sensor you wear on your skin that sends data wirelessly to a receiver or a mobile phone, so you can see your blood sugar level at any time.

Diabetes UK has more information about checking your blood sugar levels

Making changes to your diet can help control your blood sugar levels.

You should be referred to a dietitian, who can give you advice about your diet and how to plan healthy meals.

You may be advised to:

  • eat regularly – usually three meals a day – and avoid skipping meals
  • eat starchy and low glycaemic index (GI) foods that release sugar slowly – such as wholewheat pasta, brown rice, granary bread, all-bran cereals, pulses, beans, lentils, muesli and plain porridge
  • eat plenty of fruit and vegetables – aim for at least 5 portions a day
  • avoid sugary foods – you do not need a completely sugar-free diet, but swap snacks such as cakes and biscuits for healthier alternatives such as fruit, nuts and seeds
  • avoid sugary drinks – diet or sugar-free drinks are better than sugary versions. Fruit juices and smoothies can also be high in sugar, and so can some "no added sugar" drinks, so check the nutrition label or ask your health care team
  • eat lean sources of protein, such as fish

It's also important to be aware of foods to avoid during pregnancy, such as certain types of fish and cheese.

Diabetes UK has more information about diet and lifestyle with gestational diabetes

Physical activity lowers your blood glucose level, so regular exercise can be an effective way to manage gestational diabetes.

You'll be advised about safe ways to exercise during pregnancy. Find out more about exercise in pregnancy.

A common recommendation is to aim for at least 150 minutes (2 hours and 30 minutes) of moderate-intensity activity a week, plus strength exercises on 2 or more days a week.

You may be given medicine if your blood sugar levels are still not stable 1 to 2 weeks after changing your diet and exercising regularly, or if your blood sugar level is very high when you're first diagnosed. This may be tablets – usually metformin – or insulin injections.

Your blood sugar levels can increase as your pregnancy progresses, so even if they improve at first, you may need to take medicine later in pregnancy.

You can usually stop taking these medicines after you give birth.

Tablets

Metformin is taken as a tablet up to 3 times a day, usually with or after meals.

Side effects of metformin can include:

  • feeling sick
  • being sick
  • stomach cramps
  • diarrhoea
  • loss of appetite

Occasionally a different tablet called glibenclamide may be prescribed.

Insulin

Insulin may be recommended if:

  • you cannot take metformin or it causes side effects
  • metformin does not lower your blood sugar levels enough
  • you have very high blood sugar
  • your baby is very large or you have too much fluid in your womb (polyhydramnios)

You inject insulin using an insulin pen. This is a device that helps you inject safely and take the right dose.

Using an insulin pen does not usually hurt. The needles are very small, as you only inject a small amount just under your skin. You'll be shown where to inject and how to use your pen.

Depending on the type of insulin you're prescribed, you may need to take it before meals, at bedtime, or on waking.

You will be told how much insulin to take. Blood sugar levels usually increase as pregnancy progresses, so your insulin dose may need to be increased over time.

Insulin can cause your blood sugar to fall too low (hypoglycaemia). Symptoms of low blood sugar include feeling shaky, sweaty or hungry, turning paler than usual, or finding it difficult to concentrate.

If this happens, test your blood sugar, and treat it straight away if it's low. Find out how to treat low blood sugar.

You'll be given information about hypoglycaemia if you're prescribed insulin.

Find out more from Diabetes UK about types of insulin and how to take it

Gestational diabetes can increase the risk of your baby developing problems, such as growing larger than usual.

Because of this, you'll be offered extra antenatal appointments so your baby can be monitored.

Appointments you should be offered include:

  • an ultrasound scan at around week 18 to 20 of your pregnancy to check your baby for abnormalities
  • ultrasound scans at week 28, 32 and 36 – to monitor your baby's growth and the amount of amniotic fluid, plus regular checks from week 38 onwards

The ideal time to give birth if you have gestational diabetes is usually around weeks 38 to 40.

If your blood sugar is within normal levels and there are no concerns about your or your baby's health, you may be able to wait for labour to start naturally.

However, you'll usually be offered induction of labour or a caesarean section if you have not given birth by 40 weeks and 6 days.

Earlier delivery may be recommended if there are concerns about your or your baby's health, or if your blood sugar levels have not been well controlled.

You should give birth at a hospital where specially trained health care professionals are available to provide appropriate care for your baby.

When you go into hospital to give birth, take your blood sugar testing kit with you, plus any medicines you're taking. 

Usually you should keep testing your blood sugar and taking your medicines until you're in established labour or you're told to stop eating before a caesarean section.

During labour and delivery, your blood sugar will be monitored and kept under control. You may need to have insulin given to you through a drip, to control your blood sugar levels.

You can usually see, hold and feed your baby soon after you've given birth. It's important to feed your baby as soon as possible after birth (within 30 minutes) and then at frequent intervals (every 2-3 hours) until your baby's blood sugar levels are stable.

Your baby's blood sugar level will be tested starting 2 to 4 hours after birth. If it's low, your baby may need to be temporarily fed through a tube or a drip.

If your baby is unwell or needs close monitoring, they may be looked after in a specialist neonatal unit.

Any medicines you were taking to control your blood sugar will usually be stopped after you give birth. You'll usually be advised to keep checking your blood sugar for 1 or 2 days after you give birth.

If you're both well, you and your baby will normally be able to go home after 24 hours.

You should have a blood test to check for diabetes 6 to 13 weeks after giving birth. This is because a small number of women with gestational diabetes continue to have raised blood sugar after pregnancy.

If the result is normal, you'll usually be advised to have an annual test for diabetes. This is because you're at an increased risk of developing type 2 diabetes – a lifelong type of diabetes – if you've had gestational diabetes.

This video gives advice about gestational diabetes and Kimberly talks about her pregnancy after being diagnosed.

Page last reviewed: 06 August 2019
Next review due: 06 August 2022