|
 |
|
Professionals
Screening
Both the Canadian Diabetes Association and the American Diabetes Association recommend that all pregnant women be screened for gestational diabetes between 24 and 28 weeks gestation, and earlier if high risk factors are present. These factors are:
- obesity
- previous GD
- family history of diabetes
- previous large-for-dates baby
- South or East Asian, Hispanic, African, Native North American, or Pacific Islands ancestry
- multiple pregnancy
- previous birth defect
- previous stillbirth or spontaneous miscarriage
- history of gestational hypertension, urinary tract infection, polyhydramnios (ADA)
Screening consists of a 50 gm glucose load, with a plasma glucose measurement done one hour later. If the value meets or exceeds 7.8 mmol/L, then a 100 gm glucose tolerance test (GTT) is done after an overnight fast. Blood glucose values are tested before the GTT, and at one, two, and three hours following. If two or more values meet or exceed the following numbers, a diagnosis of gestational diabetes is made.
Fasting ≥ 5.3 mmol/L
1 hour ≥ 10.0 mmol/L
2 hour ≥ 8.6 mmol/L
3 hour ≥ 7.8 mmol/L ( ADA, 2004)
These women will need to follow a diet and exercise program, and may need insulin to control their blood glucose. Oral hypoglycemic agents are not currently recommended as a safe and effective choice in pregnancy. Well controlled gestational diabetes results in normal outcomes for the mother and the baby (Thompson et al, 1994).
At Risk
Abnormal Glucose Tolerance (AGT) is defined as one positive value on the GTT. In our clinic, about 20 per cent of women with AGT require insulin as well as diet to achieve normal blood glucose. For this reason, we recommend that women with AGT be treated. There are presently no outcome studies to show it is safe not to start treatment.
Women who have a high 50 gm screen but are unable to tolerate the GTT or those with asymmetrical macrosomia on ultrasound are also at risk.
Physician Referral
A physician may refer women to the clinic. Upon referral, each woman is assigned to the care of an endocrinologist. You may obtain a referral form from the clinic and fax it along with Parts 1 and 2 of the prenatal record, the latest ultrasound, and any other pertinent information. You can also download this form (PDF?)
The criteria for referral are as follows:
- type 1 diabetes
- type 2 diabetes
- gestational diabetes
- GTT with one abnormal value (AGT)
- abnormal 50 gm screen
- transfer of care
- overt hyperglycemia
- previous gestational diabetes
- asymmetrical macrosomia
- pre-pregnancy counselling
The clinic desk is open from 8 a.m. to 4 p.m. Monday to Friday, except for statutory holidays and universal closure days.
Phone: (604) 875-3135
Fax: (604) 875-2871
|
|
|
|
|
|