Chapter 9 Selected Diseases and Disorders of the Endocrine System
Gestational Diabetes Mellitus (GDM)
Zoë Soon
Overview
- Develops during pregnancy, usually in the second half.
- Often disappears after childbirth.
- Women with GDM are at increased risk for developing type 2 diabetes later in life.
Causes
- The exact cause is idiopathic (unknown).
- Thought to be related to hormones produced by the placenta:
- These hormones impair insulin action.
- Can cause hyperglycemia by:
- Impairing insulin activity
- Reducing insulin secretion
- Decreasing tissue response to insulin (insulin resistance)
Risk Factors
- Age (older age)
- Family history of diabetes
- Overweight/obesity (BMI 30+)
- Genetic predisposition
Diagnostic Screening
- Glucose challenge test (initial screening)
- Follow-up if high glucose:
- Oral glucose tolerance test to confirm hyperglycemia.
- Additional monitoring if risk factors are present.
Treatment and Lifestyle Modifications
- Insulin injections may be prescribed if needed.
- Lifestyle changes are crucial:
- Healthy diet
- Regular exercise
- Stop smoking
Complications
For Mother
- Prolonged high blood pressure can lead to preeclampsia.
- Increased risk of type 2 diabetes in the future (~5-10%).
For Baby
- Low glucose levels in fetal cells can cause seizures.
- High blood pressure may cause organ ischemia.
- Higher birth weight (over 9 pounds) increases risk of overweight and type 2 diabetes later.
Onset and Progression
- Usually slow and insidious.
- Onset typically occurs around 20 weeks gestation, as placental hormone levels rise.
Summary
- GDM is linked to hormonal changes during pregnancy impairing insulin action.
- It can be managed with lifestyle modifications and insulin therapy.
- Close monitoring is necessary to prevent maternal and fetal complications.