Now let's talk about gestational diabetes.
All pregnant women should be screened for gestational
diabetes between 24 to 28 weeks gestational age.
Now there are some women that are at high-risk and they should
be screened in the first trimester and again at 24
to 28 weeks if negative in the 1st trimester.
Let's talk about some of those high-risk factors.
So previous history of gestational diabetes.
If they are obese meaning BMI greater than 30 kilograms
per meter square.
If they have advance maternal age meaning older
than 35 years old.
Certain ethnic groups including African-American,
And then if they have a history of an infant with macrosomia.
Again these women should be screened in the 1st trimester.
There are different comlications, both on the maternal and fetal side that go along with gestational diabetes.
Possible maternal complications are increased rate of operative delivery,
development of type 2 diabetes in future, hypertensive disorders, obesity and recurrent gestational diabetes.
Fetal complications could be congenital malformations, fetal macrosomia,
perinatal death, birth injuries and neonatal hypoglycemia.
So what does the screening entail?
Well, we tell patients to eat their normal diet but not
anything too sugary.
They go to the lab, they drink a 50 gram oral glucola test.
And then after an hour their blood sugar is drawn.
Remember, some testing facilities
may use a lower value somewhere
between 130 to 140
as their positive screening limit.
But again this is a screening test.
So now we need to do the confirmation test.
So the confirmation test is actually a three hour test.
So for patients that are being diagnosed with
they have a test that involves a fasting blood sugar.
They drink a 100 gram glucose drink.
And their blood sugar is drawn at 1 hour, 2 hours and 3 hours.
So what's considered abnormal for this now screening to
diagnosing gestational diabetes.
If a fasting blood sugar is greater than 95 milligrams per
decalitre, 1 hour greater than 180, 2 hours greater than 155
or 3 hours greater than 140.
Those are the normal values.
If two or more of these are abnormal then the patient indeed
has gestational diabetes.
So initially our management involves diet modification.
However, if blood sugars are not controlled by diet then we'll
need to manage with oral hypoglycemic or insulin.
All women that are diagnosed with gestational diabetes should
be screened for overt diabetes in the postpartum period.
Now that test is a little bit different.
First women have a fasting blood sugar.
Then they drink a 75 gram oral glucose tolerance amount.
And then their blood sugar is drawn two hours later.
This can be performed anywhere between 6 and 12 weeks
Women with gestational diabetes have a 15 to 50% lifetime risk
of developing diabetes.
This is very important to make sure your patients understand.
This is one of the reasons it's important to do that postpartum
screening to see if patient has overt diabetes.
But also to make sure that they are screened annually.
Either through their primary care physician
or through their gynecologist.
So let's try a case.
A 37 year old Gravida 2 Para 1 female at 26 weeks gestation
presents to discuss the results of her 3 hour OGTT.
Her results are listed below.
A fasting blood sugar of 110 milligrams per decalitre.
1 hour of 200 milligrams per decalitre.
2 hours of 112 milligrams per decalitre.
And 3 hours of 110 milligrams per decalitre.
What is the next best managed step in her management?
Well first of all looking at those lab values,
what is her diagnosis?
Well, I see that her fasting blood sugar is greater than 95.
And her 1 hour is greater than a cut off of 180.
This gives her a diagnosis of gestational diabetes.
So for our management, do we want to.
A. Place her on insulin.
B. Start an oral hypoglycemic medication.
C. Begin antenatal testing
or D. Recommend diet modification.
What do you think?
We want to recommend diet modification.
That's the place to start.
If after two weeks of observing blood sugars, they seem to still
not be control, now we need to look at either doing
an oral hypoglycemic or we need to do insulin for management.