Gestational Diabetes Prevention: A 2026 Guide

In 2021–22, almost one in five women aged 15–49 who gave birth in an Australian hospital was diagnosed with gestational diabetes, representing 53,900 women, according to the Australian Institute of Health and Welfare. That figure changes the conversation. Gestational diabetes prevention isn't a niche concern for a small group of pregnancies. It's a practical part of preconception and antenatal care.

You can't prevent every case, and developing gestational diabetes isn't a personal failure. But you can identify risk earlier, improve the metabolic factors you can influence, and make sure screening happens at the right time. The most useful plan combines risk assessment, preconception preparation, pregnancy-safe nutrition and movement, and a clear conversation with your GP or midwife.

Why Gestational Diabetes Prevention Matters in Australia Right Now

Australian hospital data shows why prevention needs attention before pregnancy, not only after an abnormal glucose test. After age-standardisation, gestational diabetes incidence more than doubled between 2012–13 and 2021–22. Earlier national data also recorded a rise from 5% in 2000–01 to 15% in 2016–17. In 2016–17, more than 40,800 women in hospital births were affected, according to the AIHW gestational diabetes data.

Gestational diabetes develops when pregnancy-related changes make it harder for the body to keep blood glucose within the expected range. It often appears in the second or third trimester, so symptoms cannot reliably identify it. Feeling well does not remove the need for appropriate testing.

Practical rule: Prevention means reducing avoidable risk and finding glucose problems early enough to act. It does not promise that gestational diabetes will not occur.

The Australian approach is shifting towards risk-based early assessment plus universal later screening. If you have higher risk and no recent HbA1c, ask your GP whether testing belongs at the first antenatal visit. A history of gestational diabetes or an early pregnancy HbA1c of 6.0–6.4% may lead to a 75 g oral glucose tolerance test before 20 weeks, ideally at 10–14 weeks. Pregnant women without diabetes should still be tested between 24 and 28 weeks, consistent with AIHW guidance.

At an appointment, ask three direct questions: Which risk factors apply to me? Which test is appropriate now? What support would make healthier choices realistic? Preconception planning may also include an HbA1c discussion or, for some people, an OGTT discussion. Nutrition advice should stay practical. This guide to cranberry juice for pregnant women can provide pregnancy-specific context, but no individual food prevents gestational diabetes.

Understanding Your Personal Risk Profile

Your risk profile helps your clinician decide whether to assess glucose earlier. It does not predict the outcome of your pregnancy or assign blame. The AIHW risk-factor guidance outlines factors that can shape screening and prevention planning.

Risk factors that should change your appointment

A previous pregnancy affected by gestational diabetes is one of the clearest reasons to discuss early testing. The same applies if you previously had a large baby, particularly one weighing more than 4500 g or above the 90th percentile. Tell your GP about a family history of diabetes, maternal age of 40 or more, PCOS, pre-pregnancy BMI above 30 kg/m², or relevant ethnic background.

AIHW identifies Aboriginal and Torres Strait Islander, Pacific Islander, Māori, Middle Eastern and South Asian backgrounds among groups that may have higher risk. Lower physical activity, insulin resistance associated with PCOS, food insecurity and limited access to safe exercise facilities can also affect prevention options. Advice needs to fit your circumstances. “Exercise more” is not a workable plan if safety, time, money or access is a barrier.

Risk factor	Why it raises GDM risk	First action to take
Previous gestational diabetes	Glucose intolerance may recur in a later pregnancy	Ask about preconception or early pregnancy HbA1c and OGTT
Previous large baby	It may indicate unrecognised glucose intolerance in the earlier pregnancy	Tell your GP the baby's birth weight and ask whether early testing is appropriate
BMI above 30 kg/m²	Higher adiposity can be associated with insulin resistance	Request an early risk review and discuss sustainable lifestyle support
PCOS	PCOS can coexist with insulin resistance before pregnancy	Ask whether HbA1c or glucose testing is suitable before conception
Family history of diabetes	Inherited and household factors can both influence risk	Include the family history in your booking appointment
Age 40 or more	AIHW identifies older maternal age as a risk factor	Confirm whether your screening should begin at the first visit
Aboriginal or Torres Strait Islander, Pacific Islander, Māori, Middle Eastern or South Asian background	Some population groups are identified as higher risk	Ask for culturally appropriate early screening and support
Low physical activity or limited food access	These factors can make glucose-supportive routines harder to maintain	Request practical referral options, not just general advice

If you use home body-composition tracking, treat it as a trend tool, not a diagnostic test. The Venus AI Smart Scale: Body Composition & Body Fat Scale records weekly measurements and provides body-composition reports. It cannot replace pathology testing, clinical assessment or pregnancy care. For a clearer list of markers to discuss with your clinician, review these metabolic health markers.

How risks should be combined

Several risk factors should prompt a specific discussion about early testing rather than a passive wait for routine screening. One significant factor, such as previous gestational diabetes or a previous very large baby, may also justify asking about the first antenatal visit pathway. The decision depends on your history, current health and the testing approach used by your care team.

Ask: “Which of my risk factors changes the timing of my glucose testing?” Also ask whether an early HbA1c is suitable, and whether a preconception or early-pregnancy OGTT would add useful information. Bring previous pregnancy records when available, including birth weight, any gestational diabetes diagnosis and treatment details.

The aim is a documented plan: which risk factors apply, what test is appropriate now, and when later screening should occur. That makes risk assessment useful in a real appointment, rather than a list you read once and set aside.

Your Preconception Prevention Plan

A preconception plan works best when it is modular. You don't need to overhaul your life in one weekend, and you shouldn't attempt aggressive weight loss after pregnancy begins. Use the following 12-week framework as a conversation starter with your GP, especially if you have PCOS, a previous pregnancy affected by gestational diabetes, a higher BMI, or a strong family history.

Weeks 1 to 2

Book a preconception appointment and take a written list of your risk factors. Ask whether fasting glucose and HbA1c are suitable, and discuss any other blood tests your clinician considers relevant. Review rubella immunity, folate, existing medicines and conditions that may need attention before conception.

Start a pregnancy supplement plan with professional advice. Australian pregnancy care commonly includes folic acid and iodine, but the appropriate product and dose can depend on your health history, diet and medications. Don't assume that a supplement can compensate for untreated glucose intolerance.

Weeks 3 to 6

Build meals around vegetables, legumes, wholegrains, lean protein and unsaturated fats. A lower-GI pattern can be practical without becoming restrictive: choose oats, grainy bread, basmati rice, beans or lentils more often, and pair carbohydrate foods with protein or fibre.

The useful behaviour is substitution, not perfection. Replace one highly processed meal with vegetables, legumes and wholegrains, then repeat the change until it feels routine. If food cost, nausea, cultural preferences or caring duties make this difficult, ask for an accredited practising dietitian referral rather than relying on a generic meal plan.

Weeks 5 to 10

Gradually work towards the Australian Government's pregnancy activity guidance, which supports a weekly target equivalent to about 150 minutes of moderate-intensity activity. Queensland Health also identifies healthy eating, regular physical activity and appropriate gestational weight gain as prevention levers in its gestational diabetes guideline.

Start with brisk walking, swimming or stationary cycling if those activities are comfortable. Add simple resistance work such as sit-to-stand movements, wall push-ups or bodyweight exercises, provided your clinician has no concerns. If you're trying to identify fertile timing, a Venus Smart Basal Thermometer for Ovulation, Bluetooth BBT Tracker with App can automatically sync basal temperature data to an app, but fertility tracking doesn't assess glucose health.

After at least one substantive planning step, use this video as an additional visual guide:

Weeks 9 to 12

Review what you can sustain. If weight is a concern before conception, ask your GP for a safe, individualised plan. Don't pursue intentional weight loss once you're pregnant unless your maternity clinician specifically directs you.

At week 12, your clinician may decide whether repeat glycaemic testing is useful based on your initial results and risk profile. Once conception occurs, book early antenatal care promptly so risk-based testing isn't delayed. One completed action, such as arranging the appointment or starting regular walks, is more useful than waiting until you can execute the entire plan perfectly.

Nutrition and Movement During Pregnancy

Pregnancy nutrition should support steady energy, adequate nutrients and appropriate weight gain. It shouldn't become a crash diet or a rigid attempt to control every gram of carbohydrate. The Australian pregnancy activity guidance supports moderate movement, while Queensland guidance links healthy food, activity and appropriate gestational weight gain with gestational diabetes prevention.

Build the plate before counting numbers

Use a simple plate pattern: half non-starchy vegetables, one quarter lean protein and one quarter lower-GI carbohydrate. That might mean chicken and salad with chickpeas, tofu with vegetables and brown rice, or eggs with grainy toast and tomatoes.

Useful swaps include steel-cut or traditional oats instead of instant varieties, basmati rice instead of jasmine rice, and legumes several times through the week. Pair fruit with yoghurt, nuts or another protein source when you need a snack, and limit sugary drinks and heavily processed snack foods.

A sample day could look like this:

• Breakfast: Oats with plain yoghurt, berries and nuts.
• Lunch: Lentil and vegetable soup with grainy toast.
• Snack: Fruit with cheese or unsweetened yoghurt.
• Dinner: Grilled fish or tofu, roasted vegetables and a modest serve of basmati rice.
• Drinks: Water as the default, with caffeine and food choices checked against your pregnancy clinician's advice.

Food safety matters as much as carbohydrate quality. Follow Australian guidance around listeria prevention, choose safe food-handling practices and check any uncertain foods with your midwife or GP. For a further pregnancy nutrition reference, you can read nutritional needs and diet tips during pregnancy. If you're still planning conception, the Venus Ovulation Predictor Test Kit is an at-home LH test option that can help identify the fertile window, but it isn't a gestational diabetes test.

Adjust movement as pregnancy progresses

In the first trimester, continue comfortable activities and reduce intensity if nausea or fatigue is significant. In the second trimester, brisk walking, swimming and stationary cycling can remain useful, with adjustments for balance and comfort. In the third trimester, shorter sessions, prenatal yoga, mobility work and pelvic floor exercises may be more realistic than long workouts.

Aim for regularity rather than a heroic session. Break activity into manageable periods if needed, and stop to seek clinical advice for concerning symptoms such as bleeding, dizziness, chest pain, severe breathlessness or painful contractions.

If you like tracking, record three items each week: meals that felt balanced, movement minutes and any glucose readings your care team has asked you to take. For a private way to follow pregnancy milestones alongside these habits, you can track pregnancy privately with Lua.

Screening Timelines and What to Ask Your Clinician

Here is when to book each test and what to ask at each visit. The 2025–26 Australian shift toward risk-based early screening means your history should guide the first conversation, rather than waiting automatically for the routine test.

Three windows matter

Before conception or at the booking visit, tell your GP or maternity team about previous gestational diabetes, PCOS, family history, a previous large baby, BMI concerns and relevant ethnic background. Ask whether you need an HbA1c before pregnancy or at the first antenatal appointment. If you have not had recent testing, an early result can help identify pre-existing diabetes or a higher-risk pattern that needs follow-up.

Early pregnancy testing may involve an HbA1c first, followed by a 75 g OGTT before 20 weeks when your history or result indicates it. Australian guidance commonly uses an early HbA1c of 6.0–6.4% as a reason to consider an OGTT, ideally at 10–14 weeks, as outlined by AIHW. Your clinician should confirm the pathway used by your maternity service.

A borderline HbA1c should prompt a clear plan, not guesswork. Ask whether you need an early OGTT, repeat testing, or review for symptoms and other glucose results. Do not assume that a reassuring early result removes the need for later screening.

At 24 to 28 weeks, all pregnant women without diabetes should be tested again. Pregnancy-related changes in glucose regulation can appear later, so early normal results do not replace this test.

The 75 g OGTT usually requires fasting, drinking a glucose solution and providing timed blood samples. Ask the pathology service how long you will be there, whether you need to book, and what to do if nausea prevents you from completing it.

Questions to take into the appointment

• “Can I have an HbA1c at my first antenatal visit given my risk factors?”
• “Should I have an early OGTT because of my previous pregnancy, PCOS, BMI or family history?”
• “Will I still need the routine 24–28 week OGTT if early testing is normal?”
• “Which diagnostic thresholds are you using?”
• “If a result is borderline, will it be repeated, and who will explain the next step?”
• “What support is available from a dietitian, diabetes educator or maternity team?”

Under IADPSG criteria, the commonly referenced OGTT thresholds are fasting at least 5.1 mmol/L, one-hour at least 10.0 mmol/L, or two-hour at least 8.5 mmol/L. In plain language, one result at or above the applicable threshold may meet the diagnostic criteria used by the service. Your treating clinician must interpret the result, particularly while Australian guidance and local pathways continue to evolve.

Timing	Who it's for	Test	Positive threshold	What to ask
Preconception or first antenatal visit	Higher-risk women, especially without a recent HbA1c	HbA1c, with other testing as clinically indicated	Discuss the result with your GP	“Is early glycaemic testing appropriate for me?”
Before 20 weeks, ideally 10–14 weeks	Women with previous gestational diabetes or early HbA1c of 6.0–6.4%	75 g OGTT where indicated	Fasting at least 5.1, one-hour at least 10.0, or two-hour at least 8.5 mmol/L under IADPSG criteria	“Should I book an early OGTT?”
24–28 weeks	All pregnant women without diabetes	75 g OGTT	Use the thresholds specified by your maternity service	“When will I receive the result and what happens next?”

Private pathology may involve fees, while public pathways differ by location and eligibility. Ask about cost before booking, and confirm when and how the result will be communicated.

Your Gestational Diabetes Prevention Checklist

Use this as a prompt for appointments, not as a pass-or-fail scorecard. Tick what applies, write down the date of each test, and bring the list to your next antenatal visit.

Before conception

• Book a GP visit: Arrange a preconception review before trying to conceive.
• List your risk factors: Include previous gestational diabetes, a previous large baby, PCOS, family history, BMI concerns and relevant background.
• Request appropriate testing: Ask whether fasting glucose and HbA1c should be checked before pregnancy.
• Review supplements: Discuss folate, iodine, existing medicines and rubella immunity.
• Plan realistic meals: Keep vegetables, legumes, wholegrains and protein available for ordinary weekdays.
• Choose a movement baseline: Start with activities you can repeat safely and comfortably.

First trimester

• Tell your maternity team early: Don't wait for the routine appointment if you have significant risk factors.
• Ask about HbA1c: Confirm whether a booking-visit test is appropriate.
• Confirm early OGTT: Ask whether your history indicates testing before 20 weeks.
• Keep walking or moving: Build towards the Australian activity target when your clinician confirms it is safe.
• Protect regular meals: Avoid long gaps followed by large portions when nausea allows.
• Record questions: Write down unclear results and ask who will follow them up.

At 24 to 28 weeks

• Complete universal screening: Arrange the 75 g OGTT even if early results were normal.
• Ask how results are reported: Confirm the diagnostic thresholds used by your service.
• Use the plate method: Centre meals on vegetables, protein and lower-GI carbohydrates.
• Choose water regularly: Limit sugar-sweetened drinks.
• Review support: Request an accredited practising dietitian or diabetes educator referral if needed.
• Follow testing instructions: Ask the pathology provider about fasting, timing and what to do if you feel unwell.

From 32 to 36 weeks

• Attend growth and antenatal reviews: Ask your clinician to explain any findings in plain language.
• Keep activity comfortable: Continue walking, swimming, prenatal yoga or other approved movement.
• Follow glucose instructions: Only monitor at home if your care team recommends it, and record readings as directed.
• Prepare your birth questions: Discuss glucose management, medications if prescribed and newborn care.
• Plan practical support: Arrange food, transport and help with appointments where access is difficult.
• Keep the record: Bring your checklist and glucose log to each relevant review.

Prevention is built through many small, repeatable decisions, not one dramatic change. The most useful next step is to book the appointment, take your risk history with you and ask directly whether early HbA1c or OGTT testing is appropriate.

---

Venus Health Co. offers app-connected tools for tracking body-composition trends, nutrition habits and basal body temperature at home, which can help you organise information for preconception conversations without replacing clinical testing. Visit Venus Health Co. to explore the available health-tracking tools and choose what fits your pregnancy-planning routine.