Gestational diabetes mellitus or GDM for short gestational diabetes is a common condition that occurs during pregnancy specifically diagnosed roughly in the third trimester of pregnancy. As the name suggests it essentially is similar to diabetes mellitus type 2 in that you have hyperglycemia.
What are the Symptoms of gestational diabetes?
- Need to pee more often than usual
- A dry mouth
- Increase thirst
- Tiredness
How do Beta cells produce insulin?
The pancreas is an organ responsible for producing the hormone insulin. During pregnancy, there is beta cell hyperplasia, fetus cells or B cells or cells in the pancreas that produces and secret the hormone insulin. So, when a pregnant lady eats, their blood glucose rises and causes hyperglycemia. The hyperglycemia will stimulate the beta cells of the pancreas to release the hormone insulin into circulation.
The increase in insulin in the circulation will go around the body and then target specific cells. And insulin tells these cells to take up glucose from the blood in an attempt to reduce blood glucose. There is still enough blood glucose available in circulation to enter fetal circulation. So, the fetus requires glucose in order to gain energy and grow. The fetus will receive adequate glucose and so there will be normal fetal growth. The fetus will always receive glucose because of several reasons.
The first is that during pregnancy, insulin sensitivity decreases. This means that the effects of insulin on maternal tissue is reduce. Because the effects of insulin are reduce there will be more glucose in the blood. Beta cell hyperplasia in the maternal pancreas occurs because of reduced insulin sensitivity in maternal tissue. This also is a cause of the factors release by the fetus and also telling the maternal body to feed it.
Insulin resistance in gestational diabetes:
After a mother eats blood glucose level is increasing and causes hyperglycemia. Hyperglycemia stimulates the beta cells of the pancreas to release the hormone insulin into circulation. Insulin aims to target cells to increase glucose uptake in maternal tissue. But in just gestational diabetes there is insulin resistance. Therefore blood glucose is not taken up into maternal tissue as efficiently. The result of insulin resistance is hyperglycemia of the maternal circulation.
With hyperglycemia, this also travel into the fetal circulation and so there is an increase in blood glucose in the fetus. Because of hyperglycemia in fetal circulation, the fetus's pancreas thus will work by producing its own insulin. With more fetal insulin the fetal tissue will take up more glucose that is available and so there will be more growth of the fetus. The development of the fetus increases and you get a big baby. Similarly, the increase in blood glucose in maternal circulation means that the mother can have symptoms of diabetes. Which is the
- Polyuria
- Polyphagia
- Paresthesia which is not actually common but it's more so in chronic diabetes
- Polydipsia
These symptoms are not very specific to gestational diabetes. Instead, gestational diabetes is rather asymptomatic. The reason for a big decrease in insulin sensitivity and the development of insulin resistance in gestational diabetes. Because of the placenta-producing hormones such as growth hormones, CRH, and placental lactogen. A central hormone caused a decrease in insulin sensitivity to try to tell the mother to feed it with more glucose
Risk factors for gestational diabetes:
- Pregnant lady's age greater than 35 years old
- Obesity
- Family history of GDM
- Polycystic ovarian syndrome
- Certain ethnic groups including South East Asian
- Previous history of GDM
Diagnosis of gestational diabetes:
The diagnosis of gestational diabetes is actually done during screening at 24 to 28 weeks roughly gestation and this is done with a fasting blood glucose or with the oral glucose tolerance test. Fasting blood glucose is measure between weeks 24 to 28 weeks. Fasting blood glucose of greater than 5.1 millimoles per liter can help diagnose GDM.
The diagnosis of GDM can also measure with an oral glucose tolerance test. If blood glucose is greater than ten millimoles per liter after one hour of taking our glucose or greater than eight point five million milliliters two hours of taking our glucose.
These values normally should be lower because insulin should lower blood glucose But with insulin resistance or sensitivity blood glucose takes a lot longer to go down after eating glucose. On a side note diagnosing diabetes is different. Diagnosing diabetes type 2 as the seven-eleven rule .7 in 11 rule meaning a fasting glucose greater than 7 million moles per liter or a random blood glucose greater than 11 million moles per liter with symptoms of diabetes can help the diagnosis of diabetes type 2.
What are the complications during gestational diabetes?
The complications of gestational diabetes can be divide into
- Maternal Complication
- Fetal Complications
- Infant Complications
Maternal complications or mother complications of gestational diabetes include hypertensive disorders. It increased risk of infection for Cesarean section is a 50% risk of developing future diabetes type 2.
Fetal complications occur as a consequence of fetal hyperglycemia. With fetal hyperglycemia, fetal hyperinsulinemia occurs. Fetal hyperinsulinemia means that there will be more glucose uptake by fetal tissue causing macrosomia or a big baby. Fetal hyperglycemia means fetal osmotic diuresis occurs which means that the fetus will pee more because of the diuretic effects of glucose. Because the fetus's pee is more fluid will be within the amniotic sac causing polyhydramnios. fetal hyperglycemia may lead to congenital abnormalities and even stillbirth infant complications or baby complications tend to occur during delivery or right after delivery. And this is because the fetus is larger than normal there is macrosomia. Thus birth trauma can occur and this can be trauma to the baby or to the mother's genital tract.
After delivery, the fetus will not receive any more glucose from the mother because the umbilical cord is clamped. Keep in mind that there is still fetal hyperinsulinemia, which means that glucose will be taken up still. But with no more supply of glucose in the baby this means that there is hypoglycemia. Later after delivery, the baby will also have subsequent hyperbilirubinemia, hypocalcemia, and increased risk of respiratory distress syndrome which is a respiratory problem and are manageable. There's also a long-term risk of the baby developing childhood obesity.
How to recover from gestational diabetes after birth?
The management of gestational diabetes can be divided into managing the pregnancy itself and managing the baby after delivery. Maternal management or pregnancy management involves a multidisciplinary team where the obstetrician plays a vital role. A woman with gestational diabetes is a high-risk patient. The management's first line is diet and exercise. Use of diabetic medication including metformin can also be used. If this fails or if the mother prefers insulin, injections can be used. The pregnant woman needs to continuously monitor their blood glucose with a finger prick test for example at least four times a day.
Further, it is important to monitor the fetus inside the uterus using ultrasound to detect any anatomical changes to check for fetal size, to check for fetal blood flow, and also to check fetal heart rate. The management of the baby occurs postpartum after delivery and includes oxygenation because of the risk of respiratory distress syndrome. Because the baby is also in hypoglycemia there can be also the administration of extras. It is finally also important to monitor the bilirubin levels, the glucose levels continuously, and also the calcium levels.