Introduction
Gestational diabetes is a type of diabetes that affects women during pregnancy (gestation). Diabetes is a condition where there is too much glucose (sugar) in the blood.
Normally, the amount of glucose in the blood is controlled by a hormone called insulin. However, during pregnancy, some women develop higher than normal levels of glucose in their blood which insulin can’t bring under control.
The two other main types of diabetes are:
- Type 1 diabetes – when the body produces no insulin at all (often referred to as juvenile diabetes or early-onset diabetes)
- Type 2 diabetes – when the body doesn’t produce enough insulin and/or the body’s cells don’t react to insulin (insulin resistance)
Gestational diabetes usually develops in the third trimester (after 28 weeks) and usually disappears after the baby is born. However, women who develop gestational diabetes are more likely to develop type 2 diabetes later in life, so they should continue working with their health care team to monitor and manage their blood sugar, as well as having a higher incidence of pre-eclampsia and Caesarean section.
Gestational diabetes generally has few symptoms, and it is most commonly diagnosed by screening inappropriately high levels of glucose in blood samples during pregnancy.
Epidemiology
Gestational diabetes affects 3–10% of pregnancies, depending on the population studied. Babies born to mothers with untreated gestational diabetes are typically at increased risk of problems such as being large for gestational age (which may lead to delivery complications), low blood sugar, and jaundice. If untreated, it can also cause seizures or stillbirth. Gestational diabetes is a treatable condition and women who have adequate control of glucose levels can effectively decrease these risks. Most women are able to manage their blood glucose levels with a modified diet and the introduction of moderate exercise, but some require anti-diabetic drugs, including insulin.
Classification
Gestational diabetes is formally defined as “any degree of glucose intolerance with onset or first recognition during pregnancy”.
This definition acknowledges the possibility that a woman may have previously undiagnosed diabetes mellitus, or may have developed diabetes coincidentally with pregnancy.
Whether symptoms subside after pregnancy is also irrelevant to the diagnosis.
The White classification is widely used to assess maternal and fetal risk. It distinguishes between gestational diabetes (type A) and pregestational diabetes (diabetes that existed prior to pregnancy).
These two groups are further subdivided according to their associated risks and management.
The two subtypes of gestational diabetes under this classification system are:
- Type A1: abnormal oral glucose tolerance test (OGTT), but normal blood glucose levels during fasting and two hours after meals; diet modification is sufficient to control glucose levels
- Type A2: abnormal OGTT compounded by abnormal glucose levels during fasting and/or after meals; additional therapy with insulin or other medications is required
Diabetes which existed prior to pregnancy is also split up into several subtypes under this system:
- Type B: onset at age 20 or older and duration of less than 10 years.
- Type C: onset at age 10–19 or duration of 10–19 years.
- Type D: onset before age 10 or duration greater than 20 years.
- Type E: overt diabetes mellitus with calcified pelvic vessels.
- Type F: diabetic nephropathy.
- Type R: proliferative retinopathy.
- Type RF: retinopathy and nephropathy.
- Type H: ischemic heart disease.
- Type T: prior kidney transplant.
Pathophysiology
Gestational diabetes happens when the body can’t make enough insulin during pregnancy. Insulin is a hormone made in pancreas, an organ located behind stomach. Insulin helps the body to use glucose for energy and helps control your blood glucose levels.
Insulin binds to its receptor on the cell membrane which in turn starts many protein activation cascades. These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose, glycogen synthesis, glycolysis and fatty acid synthesis.
The precise mechanisms underlying gestational diabetes remain unknown. Pregnancy hormones and other factors are thought to interfere with the action of insulin as it binds to the insulin receptor, or what is called insulin resistance. The interference probably occurs at the level of the cell signaling pathway behind the insulin receptor. Since insulin promotes the entry of glucose into most cells, insulin resistance prevents glucose from entering the cells properly. As a result, glucose remains in the bloodstream, where glucose levels rise. More insulin is needed to overcome this resistance; about 1.5–2.5 times more insulin is produced than in a normal pregnancy.
Insulin resistance is a normal phenomenon emerging in the second trimester of pregnancy, which in cases of gestational diabetes progresses thereafter to levels seen in a non-pregnant person with type 2 diabetes. It is thought to secure glucose supply to the growing fetus. Women with gestational diabetes have an insulin resistance that they cannot compensate for with increased production in the β-cells of the pancreas.
Placental hormones, and to a lesser extent increased fat deposits during pregnancy, seem to mediate insulin resistance during pregnancy. Cortisol and progesterone are the main culprits, but human placental lactogen, prolactin and estradiol in combination with other placental hormones, leptin, tumor necrosis factor alpha, and resistin are involved also in the decrease in insulin resistance occurring during pregnancy.
The purpose of this hormonal effect is to allow the extra glucose and nutrients in blood to pass to the foetus (unborn baby), so it can grow.
Effects & Complications
Untreated or uncontrolled gestational diabetes can cause problems for the baby, such as:
• Being born with a larger than normal body—a condition called macrosomia—as extra glucose in mother’s bloodstream crosses the placenta, which triggers baby’s pancreas to make extra insulin, which makes him grow too large (macrosomia). Very large babies — those that weigh 9 pounds or more — are more likely to become wedged in the birth canal, sustain birth injuries or require a C-section birth.
• Early (preterm) birth and respiratory distress syndrome. A mother’s high blood sugar may increase her risk of early labor and delivering her baby before its due date. Or her doctor may recommend early delivery because the baby is large.
• Babies born early may experience respiratory distress syndrome — a condition that makes breathing difficult. Babies with this syndrome may need help breathing until their lungs mature and become stronger. Babies of mothers with gestational diabetes may experience respiratory distress syndrome even if they’re not born early.
• The baby also might be born with jaundice. Jaundice is more common in newborns of mothers who had diabetes during their pregnancy. With jaundice, the skin and whites of the eyes turn yellow. Jaundice usually goes away, but the baby may need to be placed under special lights to help. Making sure that baby gets plenty of milk from breastfeeding will also help the jaundice go away.
• Low blood sugar (hypoglycemia). Sometimes babies of mothers with gestational diabetes develop low blood sugar (hypoglycemia) shortly after birth because their own insulin production is high. Severe episodes of hypoglycemia may provoke seizures in the baby. Prompt feedings and sometimes an intravenous glucose solution can return the baby’s blood sugar level to normal.
• Type 2 diabetes later in life. Babies of mothers who have gestational diabetes have a higher risk of developing obesity and type 2 diabetes later in life.
• Untreated gestational diabetes can result in a baby’s death either before or shortly after birth.
Gestational diabetes may also increase the mother’s risk of:
• Having high blood pressure and too much protein in the urine, a condition called preeclampsia. Preeclampsia occurs during the second half of pregnancy. If not treated, it can cause problems for both mother and baby that could cause death. The only cure for preeclampsia is to give birth, or may be the need to have a cesarean section to deliver the baby early. If preeclampsia develops earlier, the mother may need bed rest and medicines, or have to be hospitalized to allow the baby to develop as much as possible before delivery.
• Having a surgery—called a cesarean section or C-section—to deliver the baby because he or she may be large.
• Becoming depressed. Depression can make the mother too tired and feel anxious, sad, or unable to cope with the changes she is facing.
• Developing type 2 diabetes and the problems that can come with this disease. Of those women with a history of gestational diabetes who reach their ideal body weight after delivery, fewer than 1 in 4 eventually develops type 2 diabetes.
Conclusion: Gestational diabetes poses a risk to both mother and child. This risk is largely related to uncontrolled high blood glucose levels and its consequences. The risk increases with higher blood glucose levels. Treatment resulting in better control of these levels can reduce some of the risks of gestational diabetes considerably.
The two main risks gestational diabetes imposes on the baby are growth abnormalities and chemical imbalances after birth, which may require admission to a neonatal intensive care unit.
Infants born to mothers with gestational diabetes are at risk of being both large for gestational age (macrosomic) in unmanaged gestational diabetes, and small for gestational age and Intrauterine growth retardation in managed gestational diabetes. Macrosomia in turn increases the risk of instrumental deliveries (e.g. forceps, ventouse and caesarean section) or problems during vaginal delivery, such as shoulder dystocia; when baby’s head passes through vagina, but baby’s shoulder gets stuck behind pelvic bone.
Shoulder dystocia can be dangerous, as baby may not be able to breathe while they are stuck.
Neonates born from women with consistently high blood sugar levels are also at an increased risk of low blood glucose (hypoglycemia), jaundice, high red blood cell mass (polycythemia) and low blood calcium (hypocalcemia) and magnesium (hypomagnesemia).
Untreated gestational diabetes also interferes with maturation, causing dysmature babies prone to respiratory distress syndrome due to incomplete lung maturation and impaired surfactant synthesis.
Risk factors
If possible, every woman should seek health care early — when she first think about trying to get pregnant — so her doctor can evaluate her risk of gestational diabetes as part of her overall childbearing wellness plan. Once she is pregnant, her doctor will address gestational diabetes as part of her prenatal care. If she develop gestational diabetes, she may need more-frequent checkups. These are most likely to occur during the last three months of pregnancy, when the doctor will monitor blood sugar level and baby’s health.
Classical risk factors for developing gestational diabetes are:
• Polycystic Ovary Syndrome (PCOS), a common endocrine system disorder among women of reproductive age. Women with PCOS may have enlarged ovaries that contain small collections of fluid — called follicles — located in each ovary as seen during an ultrasound exam. Infrequent or prolonged menstrual periods, excess hair growth, acne, and obesity can all occur in women with PCOS. In adolescents, infrequent or absent menstruation may raise suspicion for the condition.
• A previous diagnosis of gestational diabetes or pre-diabetes, impaired glucose tolerance, or impaired fasting glycaemia
• A family history revealing a first-degree relative with type 2 diabetes
• Maternal age – a woman’s risk factor increases as she gets older (especially for women over 35 years of age).
• Ethnicity (those with higher risk factors include “Nonwhite race”; African-Americans, Afro-Caribbeans, Native Americans, Hispanics, Pacific Islanders, and people originating from South Asia)
• Being overweight, obese or severely obese (body mass index (BMI) of 30 or higher) increases the risk by a factor 2.1, 3.6 and 8.6, respectively.
• A previous pregnancy which resulted in a child with a macrosomia (weighed more than 9 pounds (4.1 kilograms))
• Previous poor obstetric history
• Other genetic risk factors: There are at least 10 genes where certain polymorphism are associated with an increased risk of gestational diabetes, most notably TCF7L2.
In addition to this, statistics show a double risk of gestational diabetes in smokers.
About 40–60% of women with gestational diabetes have no demonstrable risk factor; for this reason many advocate to screen all women. Typically, women with gestational diabetes exhibit no symptoms (another reason for universal screening), but some women may demonstrate increased thirst, increased urination, fatigue, nausea and vomiting, bladder infection, yeast infections and blurred vision.
Most women who have gestational diabetes deliver healthy babies. However, gestational diabetes that’s not carefully managed can lead to uncontrolled blood sugar levels and cause problems for both the mother and the baby, including an increased likelihood of needing a C-section to deliver.
Diagnosis & Screening
Doctors use blood tests to diagnose gestational diabetes. All diabetes blood tests involve drawing blood at a doctor’s office or a commercial facility. Blood samples are sent to a lab for analysis.
WHO diabetes diagnostic criteria
Condition 2-hour glucose Fasting glucose HbA1c
Unit mmol/l(mg/dl) mmol/l(mg/dl) mmol/mol DCCT %
Normal <7.8 (<140) <6.1 (<110) <42 <6.0
Impaired fasting glycaemia
<7.8 (<140) ≥6.1 (≥110)
&
<7.0 (<126) 42-46 6.0–6.4
Impaired glucose tolerance
≥7.8 (≥140) <7.0 (<126) 42-46 6.0–6.4
Diabetes mellitus
≥11.1 (≥200) ≥7.0 (≥126) ≥48 ≥6.5
A number of screening and diagnostic tests have been used to look for high levels of glucose in plasma or serum in defined circumstances. One method is a stepwise approach where a suspicious result on a screening test is followed by diagnostic test. Alternatively, a more involved diagnostic test can be used directly at the first prenatal visit for a woman with a high-risk pregnancy.
Non-challenge blood glucose tests involve measuring glucose levels in blood samples without challenging the subject with glucose solutions. A blood glucose level is determined when fasting, 2 hours after a meal, or simply at any random time. In contrast, challenge tests involve drinking a glucose solution and measuring glucose concentration thereafter in the blood; in diabetes, they tend to remain high. The glucose solution has a very sweet taste which some women find unpleasant; sometimes, therefore, artificial flavors are added. Some women may experience nausea during the test, and more so with higher glucose levels.
Opinions differ about optimal screening and diagnostic measures, in part due to differences in population risks, cost-effectiveness considerations, and lack of an evidence base to support large national screening programs. The most elaborate regimen entails a random blood glucose test during a booking visit, a screening glucose challenge test around 24–28 weeks’ gestation, followed by an oral glucose tolerance test if the tests are outside normal limits. If there is a high suspicion, a woman may be tested earlier.
Non-challenge blood glucose tests:
When a plasma glucose level is found to be higher than 126 mg/dl (7.0 mmol/l) after fasting, or over 200 mg/dl (11.1 mmol/l) on any occasion, and if this is confirmed on a subsequent day, the diagnosis of gestational diabetes is made, and no further testing is required. These tests are typically performed at the first antenatal visit. They are simple to administer and inexpensive, but have a lower test performance compared to the other tests, with moderate sensitivity, low specificity and high false positive rates.
Screening glucose challenge test:
The screening glucose challenge test (sometimes called the O’Sullivan test) is performed between 24–28 weeks, and can be seen as a simplified version of the oral glucose tolerance test (OGTT). No previous fasting is required for this screening test, in contrast to the OGTT. The O’Sullivan test involves drinking a solution containing 50 grams of glucose, and measuring blood levels 1 hour later. If the cut-off point is set at 140 mg/dl (7.8 mmol/l), 80% of women with gestational diabetes will be detected. If this threshold for further testing is lowered to 130 mg/dl, 90% of gestational diabetes cases will be detected, but there will also be more women who will be subjected to a consequent OGTT unnecessarily.
Oral glucose tolerance test:
The OGTT should be done in the morning after an overnight fast of between 8 and 14 hours. During the three previous days the subject must have an unrestricted diet (containing at least 150 g carbohydrate per day) and unlimited physical activity. The subject should remain seated during the test and should not smoke throughout the test. The test involves drinking a solution containing a certain amount of glucose, usually 75 g or 100 g, and drawing blood to measure glucose levels at the start and on set time intervals thereafter.
The values which the American Diabetes Association considers to be abnormal during the 100 g of glucose OGTT:
• Fasting blood glucose level ≥95 mg/dl (5.33 mmol/L)
• 1 hour blood glucose level ≥180 mg/dl (10 mmol/L)
• 2 hour blood glucose level ≥155 mg/dl (8.6 mmol/L)
• 3 hour blood glucose level ≥140 mg/dl (7.8 mmol/L)
An alternative test uses a 75 g glucose load and measures the blood glucose levels before and after 1 and 2 hours, using the same reference values. This test will identify fewer women who are at risk, and there is only a weak concordance (agreement rate) between this test and a 3-hour 100 g test.
Urinary glucose testing:
Women with gestational diabetes may have high glucose levels in their urine (glucosuria). Although dipstick testing is widely practiced, it performs poorly, and discontinuing routine dipstick testing has not been shown to cause underdiagnosis where universal screening is performed. Increased glomerular filtration rates during pregnancy contribute to some 50% of women having glucose in their urine on dipstick tests at some point during their pregnancy. The sensitivity of glucosuria for gestational diabetes in the first 2 trimesters is only around 10% and the positive predictive value is around 20%.
Prevention
Ways that can lower your chances of getting gestational diabetes:
• Losing extra weight: Once you are pregnant, you should not try to lose weight. You need to gain some weight for your baby to be healthy. However, gaining too much weight too quickly may increase your chances of getting gestational diabetes. Your doctor will tell you how much weight gain and physical activity during pregnancy are right for you.
• Increasing your physical activity level before you get pregnant is effective for the prevention of gestational diabetes.
• Smoking cessation may decrease the risk of gestational diabetes among smokers.
• Monitoring blood glucose levels.
• Follow a healthy eating plan. Eat more grains, fruits, and vegetables. Cut down on fat and calories. Your health care team can help you design a meal plan.
Eating well with gestational diabetes
An important part of managing gestational diabetes relates to diet. Following a healthy eating plan will assist in:
• Managing blood glucose levels within the target range advised by your doctor
• Providing adequate nutrition for you and your growing baby
• Achieving appropriate weight changes during your pregnancy.
It is advisable to see an Accredited Practicing Dietitian to work out a meal plan that is appropriate for mum and the growing baby.
Guide for healthy eating during pregnancy
Women with gestational diabetes are encouraged to:
• Eat small amounts often and maintain a healthy weight
• Include some carbohydrate in every meal and snack (e.g. Multigrain bread, bulgur, pasta, potato, lentils, chickpeas, beans)
• Choose foods that are varied and enjoyable that provide the nutrients you especially need during pregnancy. This means foods which include: calcium (e.g. Milk and cheese), iron (e.g. Red meat, chicken and fish), folic acid (e.g. Dark green leafy vegetables lightly cooked, low in fat, particularly saturated fat(e.g. use oils such as canola, olive and polyunsaturated oils and margarines and use lean meats such as skinless chicken and low fat dairy foods)
• High in fibre
• Avoid foods and drinks containing large amounts of sugar
• Choose Basmati or Doongara rices – they have a lower glycemic index and will help you to stay fuller for longer.
• See a dietitian who can provide expert advice on the proper nutrients for you and your baby, as well as helping you make healthy food choices.
Carbohydrates
Carbohydrate foods are broken down into glucose and used for energy. To help manage your blood glucose levels, it is important to spread your carbohydrate foods over three small meals and 2-3 snacks each day. Foods that contain carbohydrate include:
• Multigrain breads and breakfast cereals
• Pasta, rice (preferably Basmati or Doongara) and noodles
• Potato (in moderation), sweet potato and corn
• Legumes such as baked beans, red kidney beans and lentils
• Fruits
• Milks and yoghurts
Carbohydrate foods that contain little nutritional value include sucrose (table sugar), soft drinks, cordials, fruit juices, lollies, cakes and biscuits.
In some instances, you may be eating the right amount (and type) of carbohydrate foods for your body, but still have high blood glucose levels. If this happens, it is important to talk to your doctor or Credentialed Diabetes Educator.
Fat
Try to limit the amount of fat you eat, particularly saturated fat. Use healthy fats like canola, olive and polyunsaturated oils and margarines, avocados and unsalted nuts. To limit your saturated fat intake, select lean meats, skinless chicken and low-fat dairy foods and avoid takeaway and processed foods.
Protein
Include two small serves of protein each day as protein is important for the growth of the baby and maintenance of healthy mum. Protein foods include lean meat, skinless chicken, fish, eggs and reduced fat cheese. These foods do not directly affect your blood glucose levels. Milk, yoghurts, custards and legumes (beans, lentils, and chickpeas) are also important sources of protein. However, remember that they also contain carbohydrate.
Calcium & iron
Calcium and iron requirements increase during pregnancy. Try to include 2-3 serves of low fat calcium rich foods each day (1 serve = 250 ml milk, 200 g of yoghurt or 2 slices of cheese). The iron from red meat, chicken and fish is readily absorbed. However, if you are a vegetarian or do not eat these foods regularly, an iron supplement or pregnancy multivitamin may be required. Discuss this with your doctor or dietician.
Other dietary considerations
Nutritious foods that will not cause excess weight gain or cause your blood glucose levels to go up can be eaten freely. These foods include fruits such as strawberries, passion fruit, lemons and limes and all vegetables (except potato, corn, sweet potato, taro, beans, lentils and chickpeas). Try to include at least 2 cups of vegetables each day.
Drinks
The best drink for your body is water, plain mineral water and soda water – try it with fresh lemon or lime for something different. ‘Diet’ or sugar-free drinks are suitable for people with diabetes.
However carbonated and caffeinated varieties can increase the risk of osteoporosis and may affect mood so should be consumed in moderation by everyone.
Alternative sweeteners
The use of intense sweeteners by people with diabetes is preferable to use of natural sugars.
Keeping active with gestational diabetes
For women with gestational diabetes, moderate intensity physical activity can help to manage blood glucose levels. ‘Moderate’ means a slight but noticeable increase in breathing and heart rate. If there are no specific obstetric or medical conditions, you should be able to safely exercise during pregnancy.
However, it is best to discuss this with your obstetrician or midwife prior to commencing any exercise regime in pregnancy.
Benefits of keeping active
Physical activity helps to reduce insulin resistance. Regular exercise, like walking, helps to increase fitness and prepares you for the birth of your baby. Physical activity also helps to keep your blood glucose levels under control.
Remember, before starting or continuing any form of physical activity, always check with your obstetrician or midwife.
It’s never too late to start moving, and there are many ways that you can keep active as a part of your everyday routine. Basically, anything that gets you moving is generally good for your diabetes and will also improve your overall feeling of wellbeing. For example, walking is a great way to move.
How to walk more each day
Below are some tips on how you can incorporate more walking into your life. It is important never to exert yourself.
• Walking to the local shops instead of driving.
• Start a ‘walking group’ with family or friends – perhaps meet at a regular time and day. This will help make sure you’re committed and help you stay in touch with your loved ones.
• Take the stairs instead of the elevator.
• Stand and move while on the phone.
• Garden.
• Buy a ‘pedometer’ (or a ‘step counter’), a small device you can clip to yourself that counts your daily steps. This will help you measure just how much walking you’re doing.
Reducing the risk of developing type 2 diabetes
While maternal blood glucose levels usually return to normal after birth, there is an increased risk for the mother developing type 2 diabetes in the future. To reduce your risk or delay the development of type 2 diabetes, keep in mind the following important points:
• Maintain or achieve a healthy weight. Balancing food intake with activity levels is the best way to maintain or reduce any excess body weight.
• Eat healthily. Limit saturated fat. Choose lean meat, skinless chicken and low fat dairy foods. Limit processed and fried foods. Eat plenty of vegetables, legumes, fruits, wholegrain breads and cereals.
• Be physically active. Aim to include at least 30 minutes of moderate intensity physical activity on most days. You should discuss your physical activity plans with your doctor prior to starting any exercise regime.
• Check blood glucose levels. It is important to have your blood glucose tested every 1-2 years. Discuss this with your doctor.
Treatment & Management
The goal of treatment is to reduce the risks of gestational diabetes for mother and child. Scientific evidence is beginning to show that controlling glucose levels can result in less serious fetal complications (such as macrosomia) and increased maternal quality of life. Unfortunately, treatment of gestational diabetes is also accompanied by more infants admitted to neonatal wards and more inductions of labor, with no proven decrease in cesarean section rates or perinatal mortality. These findings are still recent and controversial.
A repeat OGTT should be carried out 6 weeks after delivery, to confirm the diabetes has disappeared. Afterwards, regular screening for type 2 diabetes is advised.
If a diabetic diet or G.I. Diet, exercise, and oral medication are inadequate to control glucose levels, insulin therapy may become necessary.
The development of macrosomia can be evaluated during pregnancy by using sonography. Women who use insulin, with a history of stillbirth, or with hypertension are managed like women with overt diabetes.
Lifestyle
Counseling before pregnancy (for example, about preventive folic acid supplements) and multidisciplinary management are important for good pregnancy outcomes. Most women can manage their gestational diabetes with dietary changes and exercise, as mentioned above. Self-monitoring of blood glucose levels can guide therapy. Some women will need anti-diabetic drugs, most commonly insulin therapy.
Self-monitoring can be accomplished using a handheld capillary glucose dosage system. Compliance with these glucometer systems can be low. Target ranges advised by the Australasian Diabetes in Pregnancy Society are as follows:
• fasting capillary blood glucose levels <5.5 (95) mmol/L
• 1 hour postprandial capillary blood glucose levels <8.0(140) mmol/L
• 2 hour postprandial blood glucose levels <6.7 (120) mmol/L
Regular blood samples can be used to determine HbA1c levels, which give an idea of glucose control over a longer time period.
Research suggests a possible benefit of breastfeeding to reduce the risk of diabetes and related risks for both mother and child.
Medication
If monitoring reveals failing control of glucose levels with these measures, or if there is evidence of complications like excessive fetal growth, treatment with insulin might be necessary. This is most commonly fast-acting insulin given just before eating to blunt glucose rises after meals. Care needs to be taken to avoid low blood sugar levels due to excessive insulin. Insulin therapy can be normal or very tight; more injections can result in better control but requires more effort, and there is no consensus that it has large benefits.
There is some evidence that certain oral glycemic agents might be safe in pregnancy, or at least, are less dangerous to the developing fetus than poorly controlled diabetes. The oral medication metformin is better than glyburide. If blood glucose cannot be adequately controlled with a single agent, the combination of metformin and insulin may be better than insulin alone.
People may prefer metformin by mouth to insulin injections. Treatment of polycystic ovarian syndrome with metformin during pregnancy has been noted to decrease gestational diabetes levels.
Almost half of the women did not reach sufficient control with metformin alone and needed supplemental therapy with insulin; compared to those treated with insulin alone, they required less insulin, and they gained less weight. With no long-term studies into children of women treated with the drug, here remains a possibility of long-term complications from metformin therapy. Babies born to women treated with metformin have been found to develop less visceral fat, making them less prone to insulin resistance in later life.
Prognosis
Gestational diabetes generally resolves once the baby is born. Based on different studies, the chances of developing gestational diabetes in a second pregnancy, if you had gestational diabetes in your first pregnancy, are between 30 and 84%, depending on ethnic background. A second pregnancy within 1 year of the previous pregnancy has a high rate of recurrence.
Women diagnosed with gestational diabetes have an increased risk of developing diabetes mellitus in the future. The risk is highest in women who needed insulin treatment, had antibodies associated with diabetes (such as antibodies against glutamate decarboxylase, islet cell antibodies and/or insulinoma antigen-2), women with more than two previous pregnancies, and women who were obese (in order of importance). Women requiring insulin to manage gestational diabetes have a 50% risk of developing diabetes within the next five years.
Children of women with gestational diabetes have an increased risk for childhood and adult obesity and an increased risk of glucose intolerance and type 2 diabetes later in life. This risk relates to increased maternal glucose values. It is currently unclear how much genetic susceptibility and environmental factors each contribute to this risk, and if treatment of gestational diabetes can influence this outcome.