Pregnant woman testing blood sugar levels for gestational diabetes monitoring

Gestational Diabetes: A Complete Guide for Expecting Mothers

Written by LPC Editorial Team on 26. February 2026. Posted in Antenatal Care, Blog, Obstetrics.

Gestational Diabetes: A Complete Guide for Expecting Mothers

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What is Gestational Diabetes?

Gestational diabetes mellitus (GDM) is a condition characterised by elevated blood glucose levels that develops during pregnancy. Unlike type 1 or type 2 diabetes, gestational diabetes typically appears between 24-28 weeks of pregnancy and usually resolves after delivery, though it does increase the risk of developing type 2 diabetes later in life.

The condition occurs when pregnancy hormones interfere with insulin’s ability to regulate blood sugar effectively. During pregnancy, the placenta produces hormones that help the baby develop, but these same hormones can block the action of insulin in the mother’s body, a condition called insulin resistance.

When the body cannot produce enough insulin to overcome this resistance, blood glucose levels rise, leading to gestational diabetes. This typically develops in the second or third trimester when hormone levels are at their highest.

Understanding the Causes and Risk Factors

Whilst any pregnant woman can develop gestational diabetes, certain factors increase the likelihood of developing this condition. The NHS and NICE guidelines identify several key risk factors that healthcare providers consider when assessing pregnancy care.

The primary risk factors include:

Body mass index (BMI) of 30kg/m² or above: Excess weight can contribute to insulin resistance
Previous gestational diabetes: Having had the condition in a previous pregnancy significantly increases risk
Family history: A parent or sibling with diabetes increases susceptibility
Ethnicity: Women of South Asian, Black Caribbean, or Middle Eastern origin have higher risk
Previous large baby: Having previously given birth to a baby weighing 4.5kg (10lbs) or more
Age: Women over 40 have increased risk
Polycystic ovary syndrome (PCOS): This hormonal condition is associated with insulin resistance

It’s important to understand that having risk factors doesn’t guarantee you’ll develop gestational diabetes, and some women develop the condition without any identifiable risk factors.

Recognising the Symptoms

One of the challenges with gestational diabetes is that it often presents with mild or no obvious symptoms, which is why routine screening is so important. Many symptoms can be mistaken for normal pregnancy changes, making professional monitoring essential.

When symptoms do occur, they may include:

Excessive thirst: Feeling unusually thirsty despite drinking plenty of fluids
Frequent urination: Needing to urinate more often than typical for your stage of pregnancy
Fatigue: Feeling more tired than expected, even accounting for normal pregnancy tiredness
Blurred vision: Changes in vision due to fluctuating blood sugar levels
Recurring infections: Particularly thrush or urinary tract infections
Nausea: Feeling sick, especially if this develops later in pregnancy

Because these symptoms can overlap with normal pregnancy experiences, many women with gestational diabetes are diagnosed through routine screening rather than symptom presentation. This emphasises the importance of attending all scheduled antenatal appointments.

Diagnosis and Screening Process

The diagnosis of gestational diabetes typically occurs through an oral glucose tolerance test (OGTT), usually performed between 24-28 weeks of pregnancy. However, women with higher risk factors may be offered earlier testing.

The OGTT involves several steps:

Fasting blood test: You’ll need to fast overnight, then have blood taken to measure fasting glucose levels
Glucose drink: You’ll be given a glucose solution to drink
Follow-up tests: Blood samples are taken at one and two hours after drinking the solution
Results interpretation: Your healthcare team will analyse the results against established thresholds

According to NICE guidelines, gestational diabetes is diagnosed when fasting plasma glucose is 5.6 mmol/L or above, or when the 2-hour plasma glucose is 7.8 mmol/L or above. Some women may also have random glucose testing or glucose monitoring through early pregnancy scans if risk factors are particularly high.

Treatment and Management Approaches

Managing gestational diabetes focuses on controlling blood glucose levels to protect both mother and baby. The good news is that with proper management, most women with gestational diabetes have healthy pregnancies and babies.

Treatment typically follows a stepped approach:

First-line management includes:

Dietary modifications: Working with a dietitian to develop a balanced eating plan
Regular exercise: Safe, appropriate physical activity to help regulate blood sugar
Blood glucose monitoring: Regular home testing to track glucose levels
Weight management: Maintaining healthy weight gain during pregnancy

Medical intervention may include:

Metformin: An oral medication that helps improve insulin sensitivity
Insulin therapy: Prescribed when fasting glucose remains elevated despite lifestyle changes
Combination therapy: Using both metformin and insulin when required

The NHS recommends immediate medical treatment for women with fasting plasma glucose levels of 7.0 mmol/L or above, as this indicates a higher risk of complications.

Dietary Management and Lifestyle Changes

Diet plays a crucial role in managing gestational diabetes, and many women find they can control their blood glucose levels effectively through nutritional changes alone. The key is understanding how different foods affect blood sugar and timing meals appropriately.

Effective dietary strategies include:

Carbohydrate awareness: Learning to identify and portion complex carbohydrates appropriately
Regular meal timing: Eating smaller, frequent meals to avoid glucose spikes
Fibre-rich foods: Including plenty of vegetables, whole grains, and legumes
Protein balance: Ensuring adequate protein intake to help stabilise blood sugar
Healthy fats: Including sources like avocados, nuts, and olive oil
Avoiding processed foods: Limiting refined sugars and highly processed items

Exercise is equally important, with activities like brisk walking, swimming, or pregnancy yoga helping to improve insulin sensitivity. The NHS recommends at least 150 minutes of moderate-intensity exercise per week during pregnancy, unless contraindicated.

Working with healthcare professionals, including specialist midwives and dietitians, ensures that dietary and lifestyle modifications are safe and appropriate for your individual circumstances.

Monitoring Your Baby’s Growth and Wellbeing

Gestational diabetes can affect foetal growth and development, making regular monitoring essential throughout pregnancy. Elevated maternal blood glucose levels can lead to increased foetal growth, particularly in the baby’s shoulders and torso, a condition known as macrosomia.

Enhanced monitoring typically includes:

Serial growth scans: Regular ultrasound examinations to monitor baby’s size and growth patterns
Amniotic fluid assessment: Checking for polyhydramnios (excess amniotic fluid)
Foetal wellbeing tests: Including movements monitoring and potentially CTG (cardiotocography)
Placental assessment: Monitoring placental function and blood flow

These growth scans help healthcare providers track whether gestational diabetes is affecting the baby’s development and inform decisions about timing of delivery and birth planning. Regular monitoring allows for early intervention if any concerns arise.

Most babies born to mothers with well-controlled gestational diabetes are healthy, but monitoring ensures any potential issues are identified and managed promptly.

Potential Complications and Risks

Whilst gestational diabetes can be effectively managed, it’s important to understand potential complications to emphasise the importance of proper treatment and monitoring. Most complications can be prevented or minimised with good glucose control.

Maternal complications may include:

Pre-eclampsia: Gestational diabetes increases the risk of developing this serious pregnancy condition
Increased birth complications: Higher likelihood of instrumental delivery or caesarean section
Future diabetes risk: Increased chance of developing type 2 diabetes later in life
Polyhydramnios: Excess amniotic fluid leading to premature labour risk

Foetal and neonatal complications may include:

Macrosomia: Babies growing larger than average, potentially complicating delivery
Neonatal hypoglycaemia: Low blood sugar in the baby after birth
Respiratory distress: Breathing difficulties immediately after birth
Increased diabetes risk: Higher likelihood of developing diabetes in childhood or adulthood

It’s crucial to remember that with proper management and monitoring, the vast majority of women with gestational diabetes have uncomplicated pregnancies and healthy babies. These potential complications emphasise why following treatment recommendations is so important.

Birth Planning and Delivery Considerations

Having gestational diabetes may influence your birth plan and delivery timing, though many women with well-controlled gestational diabetes can have normal, vaginal deliveries. Your obstetric team will work with you to develop an appropriate birth plan based on your individual circumstances.

Key considerations include:

Timing of delivery: Most women deliver around their due date, though early delivery may be recommended in some cases
Induction considerations: Labour may be induced if there are concerns about baby’s size or maternal glucose control
Blood glucose monitoring: Glucose levels will be monitored throughout labour
Insulin management: Adjustments to insulin therapy during labour if applicable
Neonatal care planning: Ensuring appropriate monitoring for the baby after birth

During labour and delivery, your healthcare team will monitor both your blood glucose levels and your baby’s wellbeing. If you’ve been taking insulin, your dosage may need adjustment during labour as your body’s needs change.

Most hospitals have established protocols for managing women with gestational diabetes during delivery, ensuring both mother and baby receive appropriate care throughout the birthing process.

Postpartum Care and Long-term Health

For most women, blood glucose levels return to normal shortly after delivery as pregnancy hormones decrease. However, having gestational diabetes does have implications for long-term health that require ongoing attention.

Immediate postpartum care includes:

Blood glucose monitoring: Checking levels return to normal after delivery
Medication cessation: Stopping gestational diabetes medications if no longer needed
Baby’s glucose monitoring: Ensuring newborn’s blood sugar levels are stable
Breastfeeding support: Which can help regulate both mother’s and baby’s glucose levels

Long-term considerations include:

Diabetes screening: Having glucose tolerance tests 6-13 weeks postpartum and annually thereafter
Lifestyle maintenance: Continuing healthy eating and exercise habits
Future pregnancy planning: Understanding increased risk in subsequent pregnancies
Family health awareness: Monitoring children for signs of diabetes as they grow

Research shows that up to 50% of women who have gestational diabetes will develop type 2 diabetes within 10 years, making long-term monitoring and preventive measures crucial for maintaining health.

How the London Pregnancy Clinic Can Help

At the London Pregnancy Clinic, we understand that a gestational diabetes diagnosis can feel overwhelming. Our experienced team provides comprehensive support and monitoring throughout your pregnancy journey, ensuring you receive the highest standard of care in a comfortable, private setting.

Our gestational diabetes management services include:

Specialist consultations: Access to consultant obstetricians with expertise in high-risk pregnancies
Advanced monitoring: State-of-the-art ultrasound equipment for detailed growth and wellbeing assessments
Flexible appointment scheduling: Regular monitoring appointments that fit around your schedule
Comprehensive care coordination: Seamless communication with your NHS team and other healthcare providers
Educational support: Detailed guidance on managing your condition and understanding your care plan

Our specialist sonographers use the latest ultrasound technology to monitor your baby’s growth and development, providing detailed assessments that complement your NHS care. We offer pregnancy scan packages designed specifically for women requiring enhanced monitoring.

Located in central London with convenient appointment times, we make it easier for you to access the additional monitoring and support you need during your pregnancy with gestational diabetes.

Final Thoughts

Receiving a gestational diabetes diagnosis can initially feel daunting, but it’s important to remember that this condition is manageable and most women go on to have healthy pregnancies and babies. With proper monitoring, lifestyle adjustments, and medical support when needed, you can maintain excellent health throughout your pregnancy.

The key to successful management lies in working closely with your healthcare team, following dietary and lifestyle recommendations, and attending all scheduled monitoring appointments. Regular blood glucose testing and foetal monitoring ensure that both you and your baby remain healthy throughout pregnancy.

If you’re managing gestational diabetes or have concerns about your pregnancy, the London Pregnancy Clinic is here to provide expert care and support. Our team of specialists can work alongside your NHS care to ensure you receive comprehensive monitoring and guidance throughout your pregnancy journey. Contact us today to learn how our services can support your healthy pregnancy.

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