The emergence of diabetes during pregnancy is referred to as gestational diabetes. Treatment of gestational diabetes requires a multidisciplinary approach. Here, I present a case of a patient with gestational diabetes mellitus. But before that, let's discuss some key points pertaining to gestational diabetes mellitus.

What is gestational diabetes?

Gestational Diabetes is defined as:

• Any gestational age with fasting blood sugar levels of 92 mg/dL or higher.

• At least Following a 75g, two hour oral glucose tolerance test (GTT) between weeks 24 and 28, at least one of the following results were abnormal: 

  • Fasting blood glucose of 92 mg/dL (5.1 mmol/L) or more or one-hour plasma glucose of 180 mg/dL (10.0 mmol/L) or more or two-hour blood glucose of 153 mg/dL (8.5 mmol/L) or more.

What is Overt Diabetes?

Over diabetes means:

• 126 mg/dL (7.0 mmol/L) or more for fasting blood glucose 6.5% or more  
• For glycated haemoglobin using a standardised assay 200 mg/dL 
• 11.1 mmol/L or more for random blood sugar.

How to perform oral glucose tolerance tests?

1. One-step approach (IADPSG consensus):

:After an overnight fast of at least 8 hours, carry out a 75 gramme OGTT. Any time one of the following results is higher than normal, gestational diabetes is  diagnosed.

• Fasting:  92 mg/dL (5.1 mmol/L)
• 1 hour: 180 mg/dL (10.0 mmol/L)
• 2 hour: 153 mg/dL (8.5 mmol/L)

2. Two-step approach (NIH consensus):

Perform a 50-g non-fasting Glucose tolerance test. If plasma glucose exceeds 140 mg/dl proceed to 100-g oral glucose tolerance test (Step 2 – after an overnight fast). Diagnosis of gestational diabetes mellitus is made when any two values are exceeded.             Carpenter/Coustan            or                     NDDG Fasting             95 mg/dL                                                  105 mg/dL 1 h                 180 mg/dL                                                   190 mg/dL 2 h                 155 mg/dL                                                  165 mg/dL 3 h                 140 mg/dL                                                  145 mg/dL

What are the target blood sugars in a patient with GDM?

Blood sugar targets as per the ADA (American Diabetes Association) are as follows:

• 5.3 mmol/L or less for fasting blood sugar, or 95 mg/dL or less.
• Blood glucose levels of no more than 140 mg/dL (7.8 mmol/L) one hour after meals.
• A glucose concentration of 120 mg/dL (6.7 mmol/L) or less two hours after eating.

What complications may arise if the blood sugars are not controlled during pregnancy?

The following are some of the risk factors that the patient might develop if the blood glucose is not controlled during pregnancy:

• Metabolic complications like hypoglycemia, hyperbilirubinemia, hypocalcemia, and erythremia.
• Preeclampsia
• Increased Perinatal mortality
• Fetal organomegaly (hepatomegaly, cardiomegaly)
• High chances of Operative delivery
• Fetal macrosomia
• Neonatal respiratory problems and
• Birth trauma
• Oligo/ Polyhydramnios

Who is at risk of developing gestational diabetes mellitus?

• Those who have a first-degree relative with diabetes.
• During pregnancy, a woman's weight must be at least 110 percent of her optimal body weight, and her BMI must be higher than 30 kg/m2.
• Older than 25 years old
• Prior birth of a child weighing more than nine pounds (4.1 kg)
• Patients who are South or East Asian, African-American, Native American, Hispanic-American, or Pacific Islander.
• Prior prenatal loss or the birth of a child with malformations
• Urinate with blood at the first prenatal appointment
• Poor glucose tolerance in the past
• Hypertension or pregnancy-related hypertension
• Current use of steroids
• Polycystic ovary syndrome
• Metabolic syndrome

Let's discuss our patient ...

24 years of age female who is 6 months pregnant. She works at a company as a PA from 09:00 Am to 4:00 Pm. Her diet mostly consists of two major meals i.e. breakfast and dinner. She has had diabetes in her previous pregnancy and was treated with metformin. After her last child, she was alright and her blood sugars were well controlled. Over the past 2 months, her blood sugars have been as follows:

• Fasting blood glucose: 110 - 170 mg/dl
• Random blood glucose: 130 - 210 mg/dl

She was started on metformin but her blood sugars remained high.

How should this patient be managed?

Leave your comments below

I started her on premixed 70/30 insulin twice daily and asked her to check her blood sugars regularly. She was also given a diet plan and was asked to do a brisk walk regularly. I planned to start her on a basal-bolus regimen of insulin i.e. rapid-acting insulin two to three times before each meal and basal long-acting insulin once daily if her sugars remained high. Along with her gestational diabetes treatment, she was on a regular follow up with her gynecologist. Fortunately, her sugars remained within the target ranges after a slight modification in the dose.

Next scenario of gestational diabetes treatment will be uploaded later ... If you have any cases for discussion, send me @ emedz.net@gmail.com