Gestational diabetes mellitus(GDM): Causes, symptom and management

Gestational diabetes mellitus (GMD) or diabetes complicated by pregnancy is far common in temperate countries than in tropics.  In the pre-insulin days, diabetic women failed to menstruate and conception was usually ruled out.

With the advent of insulin, pregnancy occurs in the presence of diabetes.  Sometimes, diabetes is noticed for the first time in pregnancy.  Pregnancy is believed to unmask the signs and symptoms of diabetes in women with latent diabetes. Gestational diabetes mellitus needs multidimensional approaches to ensure the safety of both mother and baby.

The prediabetic state should be suspected in women who give the following history:

  1. Delivery of babies weighing 4.5kg or over, with a family history of diabetes;
  2. Repeated abortions, stillbirths, or early neonatal deaths;
  3. Hydramnios complicating previous pregnancies in the absence of multiple pregnancy;
  4. Recurrent pre-eclamptic toxaemia in previous pregnancies.

Such women should be referred to by the midwife to a big hospital where facilities are available for dealing with such cases.

Gestational diabetes mellitus

What is gestational diabetes mellitus?

Gestational diabetes mellitus (GDM) is a metabolic disorder of carbohydrate intolerance resulting in hyperglycaemia of variable severity with its onset or first recognition during pregnancy.

The midwife should suspect diabetes in women who give this type of history as well as women who show evidence of the following:

  1. Increasing loss of weight despite adequate intake of food;
  2. Extreme thirst(polydipsia);
  3. Passage of excessive amount of urine(polyuria);
  4. Drowsiness;
  5. Vaginal discharge with pruritus suggestive of infection with candida albicans;
  6. Presence of sugar in the urine;
  7. Presence of acetone in the urine in the absence of vomiting.

Diagnosis of gestational diabetes mellitus

All such patients are referred to the doctor. The diagnosis is confirmed in the hospital by estimating the fasting blood sugar level which is usually high in diabetics (about 120mg per 100ml of blood or more. The normal fasting blood sugar level is 80—100mg per 100ml).  The glucose tolerance test is also used to confirm the diagnosis when a typical diabetic curve is obtained.

Types of diabetes mellitus

The two types of diabetes usually described are:

  1. The juvenile insulin-sensitive diabetes
  2. The “obese” diabetes occurring in older women age 30 years and above) which is usually not very sensitive to insulin. It responds to oral antidiabetic drug (e.g. chlorpropamide and tolbutamide) and to dietary adjustment.
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Risk factors of gestational diabetes mellitus

Nursing diagnosis of a woman with Gestational diabetes mellitus (GDM)

  1. Deficient fluid volume related to increased urinary output evidenced by excessive thirst.
  2. Imbalanced nutrition less than body requirements, related to poor glucose metabolism evidenced by weight loss.
  3. Risk for infection related to impaired peripheral tissue perfusion.
  4. Risk for injury related to insulin deficiency.
  5. Activity intolerance related to altered metabolic rate evidenced by her inability to perform activities of daily living.
  6. Risk for activity intolerance related to altered metabolic rate.

How to manage gestational diabetes mellitus

All cases of diabetes require dietary control. The diabetic physician and dietician are always consulted in all cases of pregnancy complicating diabetes. The mother is advised on taking mild exercises, avoiding too much carbohydrate and increasing intake of fruits and vegetables. If the hyperglycaemia fails to be controlled, the woman may be placed on insulin injection which is also safe during pregnancy.

The diabetic baby

The diabetic baby is usually fat, flabby and oedematous, weighing 4 to 4.5kg or over.  Despites its enormous size, it is a premature or immature baby that needs the same special care and attention as  a full-term baby weighing about 1.5kg. 

The first 48 hours of the life of a diabetic baby are fraught with hazards and the baby runs the risk of respiratory complications often caused by poor expansion of the lungs, inhalation of stomach contents and hyaline membrane disease. As the oedema subsides, the baby loses weight very rapidly and tends to chill very easily.

Macrosomic baby caused by GDM

Nursing diagnosis for a baby born by a woman with Gestational diabetes mellitus (GDM)

  1. Risk for trauma related to fetal macrosomia (over weight).
  2. Risk for infection related to prolonged labour and birth manipulations.
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Nursing care of diabetic baby

At birth, the airways must be adequately cleared and a stomach tube passed to empty the stomach and prevent regurgitation and subsequent aspiration of stomach contents. If the baby has a lot of mucus, it should be put on its side with a slight head-down tilt or allow for the drainage of mucus.

The airways should be aspirated at regular intervals and the baby closely monitored.  Oxygen by mask or nasal catheter is administered as often as necessary.

The baby is watched for signs of cyanosis and respiratory embarrassment. Feeding is managed as that of a premature baby. Where the baby is ill or disinclined to suck, spoon feeding may be employed. Over-feeding is avoided so as to prevent regurgitation and subsequent aspiration of stomach contents. Precautions are also taken to prevent infection.

Metabolism of carbohydrate in pregnancy /effect of pregnancy on diabetes

Pregnancy is diabetogenic in the sense that insulin and carbohydrate metabolism is altered in order to make glucose readily available to the fetus. There is progressive hyperplasia of the pancreatic beta cells resulting in the secretion of 50% more insulin (hyperinsulinaemia) by the third trimester. This is due to increasing levels of oestrogen, progesterone and prolactin.

There is reduction in effectiveness of insulin due to the presence of insulin antagonists (progesterone, human placental lactogen, and cortisol) and also there is diminished tissue responsiveness to insulin. Collectively, these result in blood glucose levels that are higher aftermath and remain raised for longer periods than in the non-pregnant state. 

 Glucose is therefore more readily available to the feto-placental unity. This is considered to be a glucose-sparing mechanism (diabetogenic effect of pregnancy). This mechanism enables the large quantities of glucose to be taken up by the maternal circulation and transferred to the fetus through the placenta.  These take place by the process of facilitated diffusion. 

Pre-pregnancy insulin sensitivity is restored immediately is delivered due to reduction in insulin resistance. Gestational diabetes is most likely to emerge during the third trimester when the extra demands on the pancreatic beta cells precipitate glucose intolerance.   If the mother is diabetic, she does not have the capacity to increase insulin secretion due to altered carbohydrate metabolism in the maternal and fetal system.

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Complication of gestational diabetes mellitus

The effects of diabetes on pregnancy and on the fetus if not well controlled can never be underestimated. These may be divided as follow:

Effect of diabetes on pregnancy

  1. Low fertility rate in  untreated cases
  2. Urinary tract infection such as candidiasis
  3. Pregnancy-induced hypertension or pre-eclampsia due to poor glucose regulation.
  4. Calcification of blood vessels resulting in high peripheral resistance.
  5. Possible kidney involvement due to narrowing of blood vessels.
  6. Retinopathy due to narrowing of blood vessels
  7. There could be dystocia (difficult labour)  and inertia due to  large baby(fetal macrosomia)

Effects of Gestational diabetes mellitus on the fetus

  1. Abortion especially in untreated cases.
  2. Placental insufficiency due to premature aging of the placenta.
  3. Congenital malformations
  4. Malpresentation due to large baby
  5. Prematurity
  6. Hydramnios: This is believed to be related to the sugar that is excreted in the urine by the fetus in-utero.
  7. Hyperglycaemia due to excess glucose  in blood resulting in its (glucose) excretion in urine
  8. Abnormally large baby in the last weeks of pregnancy with all the organs enlarged
  9. Possible asphyxia neonatorum because of the large baby leading to difficult labour.
  10. Intrauterine death(IUD) and stillbirths
  11. Perinatal death(i.e. the baby may die in the first week of life)
  12. Neonatal hypoglycaemia (this could be due to trauma sustained) during labour.
  13. Neonatal hyperbilirubinaemia
  14. Metabolic problems such as pancreatic hypertrophy resulting in-utero.

The bottom line

Gestational diabetes mellitus tends to endanger the lives of both mother and foetus. However, if the woman is a booked patient in the hospital who attends her antenatal care regularly, those complications are far more likely to be prevented. Women who are overweight or obese should endeavour to achieve a healthy weight before getting pregnant. This helps to lower the risk of gestational diabetes mellitus.