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Gestational Diabetes Screening or Glucose Tolerance Testing 

What is Gestational Diabetes?


During pregnancy, the body is required to change its glucose metabolism a little bit so that the baby is constantly supplied with adequate levels of glucose. This is a normal and healthy physiological reaction. However, when a mother has glucose metabolism problems, this normal physiological change can be too much for her body. Her pancreas is forced to produce insulin too often, her glucose levels fluctuate widely, and, over time, her body “resets” itself to this irregular glucose/insulin level. Therefore, Gestational Diabetes Mellitus (GDM) is the onset of Type II diabetes during pregnancy. It can be mild or severe and it can go away after pregnancy. It may occur in one pregnancy but not again in a later pregnancy. It sometimes resolves with targeted nutritional planning, exercise, and supplements, and sometimes needs to be managed with medication and/or insulin.


What are the risks of GDM?


GDM can cause problems for both the mother and the baby, during and after pregnancy. The mother increases her risk of pre-eclampsia (extreme rise in blood pressure), hypertension, and polyhydramnios (too much amniotic fluid). The baby is at higher risk of birth injury or trauma due to being macrosomic (larger than normal). The baby may also suffer from low blood sugar (hypoglycemia) just after birth, increasing the likelihood of breathing difficulties, resuscitation, and hospitalization. Additionally, the mother’s risk of developing Type II diabetes in the years after pregnancy increases substantially, thus causing all the health problems associated with diabetes. A very important but minimally understood negative effect of GDM is the “resetting” of the baby’s own metabolism that occurs as the baby’s pancreas, brain chemicals and body cells react to the high levels of glucose during pregnancy. The child is pre-programmed to crave sugar, have radical swings in insulin levels and gain weight. This vastly increases risk of the baby developing Type II as a child, teenager, or adult. Diabetes can be intergenerational; that is, if you have GDM (or Type I or II) and your baby is a girl who goes on to have her own children, the risk of her children developing diabetes is increased.


Am I likely to develop GD?


The following are risk factors for developing gestational diabetes:

- Previous baby >9 pounds

- Previous baby with congenital birth defects

- Previous unexplained stillbirth

- Previous pregnancy with GD

- Multiple miscarriages

- Family history of diabetes (parent, sibling)

- BMI exceeding 26

- Excess amniotic fluid

- Recurrent infection (especially yeast)

- Pre-eclampsia

- Chronic hypertension

- Polycystic ovarian syndrome (PCOS)

- Hispanic, Native American, Asian/Pacific Islander, or African American

- Maternal birth weight >9 pounds

- Maternal central fat distribution

- Cigarette smoking

  • Multiple pregnancy

  • Chronic steroid use


What tests are available?


The American College of Obstetricians recommends universal screening for all pregnant women around 28 weeks of pregnancy (+/- 2 weeks). Women at increase risk for developing GDM, such as those with significant obesity, a strong family history of type 2 diabetes, or a personal history of GDM, glucose intolerance or glucosuria are encouraged to have screening as early as possible in pregnancy and then be rescreened at the 24-28 week of pregnancy or at any time they may have signs or symptoms. 


The glucose tolerance test (GTT) is the standard of care when it comes to screening procedures. It involves assessing plasma glucose 1 hour after consumption of a 50-g glucola drink. If this initial screen is abnormal, it is followed by a 3-hour, 100-g GTT for diagnosis of gestational diabetes. The initial screening is given without regard to prior nourishment, although it may be more sensitive if tested following fasting.


We offer all versions of the GTT in our office. You have a choice to drink the standard glucola drink (without dye), the option for you to eat an extra-large meal of “normal” food, as well as keeping a food log and performing finger sticks daily using a home glucometer to monitor your blood sugar readings.


What if I am diagnosed with GDM?

We take a proactive approach from your very first visit to focus on nutritional intake and physical movement to help encourage a healthy pregnancy overall, but if you are diagnosed with GDM we will focus on nutritional education for your particular situation, have you purchase a glucometer to keep at home to monitor your blood sugar readings, and offer referral options to outside nutritionists as well. If your blood sugar is managed using dietary measures, your homebirth can proceed as normal. 


How Will My Baby Be Treated After Birth If I Am Diagnosed with GDM?


Breastfeeding should be immediate and often. Newborn babies born to mothers with GDM may experience a dangerous drop in their own blood glucose level following birth. Your midwife will monitor the baby’s glucose closely and you are encouraged to call her with any concerns following her departure. A baby with low glucose levels may appear shaky, have difficulty eating, or may be difficult to arouse.


Informed Consent


Screening for gestational diabetes is controversial. Evidence is clear that GDM imposes risk on both mother and baby, yet evidence is not as solid regarding the effects of management following diagnosis of GDM. However, the test itself imposes minimal risk and can assist in optimizing not only your current pregnancy, but your lifelong health. 

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