Identifying Gestational Diabetes and its Causes

Gestational diabetes mellitus (GDM) is becoming more common, which calls for a deeper understanding of this disorder and its causes. 

Diabetes diagnosis during pregnancy is not only daunting for an expectant mother but unsafe for her and her offspring. A substantial risk of stillbirth can occur in pregnancies with GDM, mainly when the patient’s glucose levels are not well managed. The main effects of GDM include cesarean delivery, birth weight >90th percentile, hypoglycemia of the infant, and serum C peptide levels >90%. GDM’s secondary effects include premature delivery or <37 weeks of pregnancy, potential harm to the infant and required ICU for the newborn, hyperbilirubinemia, and preeclampsia. Insulin resistance can also occur in women experiencing GDM. In 1882 J. Matthews Duncan initially detected that diabetes could occur during pregnancy and then conclude after the pregnancy. However, in 1957, the term gestational diabetes was coined by Carrington et al. Defining the essential factors that exist for this disorder may assist in a reduction of morbidities, as well as early diagnosis, treatment, and decrease of its frequency. 

The trial by Wagan et al. was created to identify the factors and incidence of GDM and evaluate the significance of its effects. The trial was a cross-sectional study conducted in Civil Hospital Karachi, Pakistan, from March 2017 to August 2017 and included 185 pregnant participants. Those patients who were 20 to 40 years old, parity ≥1 with gestational age >24 weeks, were eligible for the study. Cut-off levels of fasting blood glucose (FBG) were 95 to 125mg/dL and two hours glucose at 153 to 199mg/dL, which were the basis of labeling GDM and its factors. Participants were excluded if they did not provide consent, who had a history of hypertension, endocrine dysfunction, or diabetes mellitus. Participants were called to the outpatient department for the overnight 6 to 8 hour fast; FBG was measured by reflectometer by the oral glucose tolerance test (OGTT) with 75grams of glucose taken two hours later. Statistical analysis used during the trial to recognize the relation of the groups was the chi-squared test or Fisher’s exact test.  

The following factors were identified with the correlation of developing GDM: high maternal age (>35 years; p=<0.001), high parity (>5;p=0.018), high BMI (>25kg/m2; p=0.543), history of prior GDM (p=<0.001), and family history of GDM (p=<0.001). The majority of the women were >30 years of age, 68.65%, while 16.22% were above >35 years. The majority of the women were multiparous, 52.43%; 32.97% were primiparous, and 14.59% were grand multiparous. It was interesting to know the trial included monthly incomes of patients, where 87.03% of the women had a total monthly income of >10,000 Pakistan Rupee. Higher education obtained was 3.24%, 19.46% of the women were illiterate; there were no substantial results between these groups when stratification analysis was performed (p=0.0624). Important factors noted were high parity (>5), high maternal age (>35 years), history of GDM, low economic state, and lack of education. The frequency of GDM in the cohort was 9.73%. Previous literature has indicated that increased maternal age and history of prior GDM enhance the probability of developing the disease, which aligns with the current study. The family background of diabetes and GDM has proven to correlate as indicated by the literature and aligns with the study performed. Globally, GDM has affected approximately 15% of pregnant women, and it is recommended that women over 35 years of age and a BMI >25kg/m2 be evaluated for the disorder. It is crucial to go beyond this study and assess this specific population who appear to be at increased probability of acquiring GDM. 

Practice Pearls: 

• The factors associated with the cause for GDM are maternal age >35 years old, high parity >5, high BMI >25kg/m2, history of GDM, family background of GDM, low economic status, and lack of education. 
• The estimated risk of GDM is correlated to a family background of diabetes and high maternal age. 
• The occurrence of GDM was 9.73% in the current study; increased morbidities to the mother and her baby are associated with GDM. Therefore, early examination and discovery are vital toward improving outcomes. 

References for “Identifying Gestational Diabetes and its Causes”:
Coustan, Donald R. “Gestational diabetes mellitus.” Clinical chemistry vol. 59,9 (2013): 1310-21.  

Wagan, Nazia, et al. “Factors Associated with Gestational Diabetes Mellitus: A Cross-Sectional Study.” Cureus, 11 Aug. 2021,  

Moyer, Virginia A, and U.S. Preventive Services Task Force. “Screening for gestational diabetes mellitus: U.S. Preventive Services Task Force recommendation statement.” Annals of internal medicine  

Trina Maglalang RPh, PharmD Candidate 2022 University of Colorado Skaggs School of Pharmacy