Symptoms of Gestational Diabetes
Gestational diabetes mellitus (GDM) is typically asymptomatic, which is why universal screening is recommended for all pregnant women at 24-28 weeks of gestation. 1
Classic Diabetes Symptoms
While most women with GDM do not experience symptoms, some may present with the classic symptoms of diabetes:
- Polyuria (excessive urination) 1
- Polydipsia (excessive thirst) 1
- Unexplained weight loss (less common in GDM than in other types of diabetes) 1
Risk Factors for GDM
Since symptoms are often absent, it's important to recognize risk factors that increase the likelihood of developing GDM:
- Age greater than 25 years 1, 2
- Obesity or BMI ≥30 kg/m² 1, 2
- Family history of diabetes in first-degree relatives 1, 2
- Personal history of previous GDM 1, 2
- Previous delivery of a macrosomic baby (>4500g) 1, 3
- History of polycystic ovary syndrome 1, 2
- High-risk ethnicity (Arab, South/Southeast Asian, Latin American, Native American, African American, Pacific Islander) 1, 3
Physiological Changes in GDM
GDM develops due to specific physiological changes during pregnancy:
- Deterioration of glucose tolerance occurs normally during pregnancy, particularly in the 3rd trimester 1
- Insulin resistance increases throughout pregnancy, especially in the third trimester 1
- Women with GDM may be at higher risk for ketosis even with only moderately elevated blood glucose levels 1
Complications That May Present as Symptoms
While direct symptoms may be absent, GDM can manifest through complications:
- Recurrent vaginal infections (due to glycosuria) 1, 3
- Glucosuria (glucose in urine) 1, 3
- Visual changes (rare) 1, 3
- Increased thirst and urination 1
Diagnostic Criteria
Since symptoms are unreliable, diagnosis relies on laboratory testing:
- Screening is recommended for all pregnant women at 24-28 weeks of gestation 1
- High-risk women should be screened at the first prenatal visit 1, 2
- Diagnosis is made using either a one-step or two-step approach with oral glucose tolerance testing 1, 2
Clinical Implications
The absence of symptoms makes screening crucial:
- GDM complicates approximately 7% of all pregnancies (range 1-14% depending on population and diagnostic criteria) 1
- If left untreated, GDM increases risks of maternal and fetal complications including preeclampsia, macrosomia, and shoulder dystocia 1, 3
- Women with GDM have a 50-60% lifetime risk of developing type 2 diabetes 4, 5
Key Points for Clinicians
- Do not rely on symptoms to identify GDM as most cases are asymptomatic 1
- Follow established screening protocols based on risk factors 1, 2
- Early detection and management are essential to prevent complications 1, 3
- Post-delivery follow-up is critical as women with GDM should be screened for persistent diabetes at 4-12 weeks postpartum 1, 4