Diabetes Mellitus:
A metabolic disorder whereby the body cannot utilise glucose effectively to produce energy. This may be due to lacking or reduced production of insulin, and/or insulin resistance. Insulin is a hormone produced in the beta cells of the pancreas, which acts as a 'key' to all the body's cells, allowing glucose (sugar) to enter the cells and be used to produce energy. Absent or low levels of insulin mean that circulating glucose levels in the blood stream rise. Insulin resistance is when the body's tissues cannot use the insulin effectively, and so there is a reduction in the amount of glucose that is allowed to enter the cells. High levels of glucose in the bloodstream are harmful to the body's tissues, and can have very damaging effects on the eyes, kidneys, nerves, blood pressure, heart, feet and other systems.
Gestational Diabetes is a condition where glucose tolerance is impaired, and which arises or is first discovered in pregnancy. The condition reverts back to normally following delivery of the baby. Incidence is 3-12% of all pregnancies. Women who are found to have gestational diabetes are at increased risk of developing type 2 diabetes in later life (30-40%). When glucose levels are high in the blood, the kidneys filter out some of the glucose, and so it is present in urine. As such, gestational diabetes is normally discovered when glucose is found on urinalysis is performed in antenatal checks. However, this is not diagnostic of gestational diabetes. (See diagnosis).
In pregnancy, hormones are secreted by the placenta. One hormone in particular (human placental lactogen) increases the resistance of the body's tissues to insulin. To compensate for this, the pancreas produces more insulin (normally three to four times the normal amount). However, in women whose insulin production was only just adequate prior to pregnancy, the levels of insulin produced in pregnancy are not sufficient, and symptoms of diabetes may become apparent. On occasion, diabetes mellitus was an already pre-existing condition, but only picked up in pregnancy. In these cases, this can only be ascertained following delivery of the baby, when pregnancy hormones revert to normal levels.
Some of the Signs and Symptoms:
Polydipsia (increased thirst)
Polyuria (increased urination)
Unexplained tiredness or weight loss (as the body cannot produce enough energy, and so uses fat deposits for energy instead of glucose)
Repeated urinary tract infections (as bacteria thrive on the glucose that is present in the urine)
Repeated thrush (for the same reasons as above)
Glycosuria
Blurred vision (as the eyes may become damaged).
Risk factors:
Previous baby weighing > 4.5 kg.
Previous unexplained perinatal death.
Obesity with BMI > 27.
Close family relative with type 2 diabetes.
Glycosuria on two occasions.
Previous baby with congential malformations.
Unexplained severe polyhydramnios.
Diagnosis of Diabetes (as guided by the World Health Organisation): If classic symptoms are present (e.g. polydipsia, polyuria)
One fasting venous glucose test of > 7.0 mmol/L
or
One random venous glucose test of > 11.1 mmol/L
If asymptomatic, or on finding glycosuria
At least two tests venous glucose tests with results ranging in the diabetic range.
Management of Gestational Diabetes:
Close monitoring of venous and capillary glucose levels (four times daily) and treatment, either by diet control or medication. Medication may involve administering insulin injections or medication which encourages the pancreas to produce more insulin.
Retinal screening
Consultations with dietician.
Clinics with the medical obstetric team - including the consultant endocrinologist.
Planning the birth, which is deemed 'high risk' and requires close monitoring and control of blood glucose levels.
Scans looking at fetal growth.
Complications:
Fetal macrosomia.
Fetal malformation.
Polyhydramnios.
Shoulder dystocia.
Perinatal death.
Urinary tract infections.
Thrush.
Pregnancy induced hypertension.
Prematurity.
Risk of child developing diabetes in later life.
http://www.labtestsonline.org.uk/ http://www.diabetes.org.uk/Guide-to-...onal_diabetes/ http://www.diabetes.org.uk/Guide-to-...onal_diabetes/ http://diabetes.niddk.nih.gov/dm/pub...onal/index.htm
Medforth, J., Battersby, S., Evans, M., Marsh, B. and Walker, A. (2006)
Oxford Handbook of Midwifery. Oxford: Oxford University Press.
Further Resources: Gestational Diabetes Video Books