CPM Summer 2018 - 23

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regnancy is a unique time in the life
of a family and can unmask current
or future conditions for the woman
and even for her children. In 1946, an
article in the New England Journal of Medicine
raised the possibility of gestational diabetes
but no formal recommendations for care were
made. This was an early recognition of altered
metabolism of glucose in pregnancy. In 1964,
John B. O' Sullivan and his statistician, Claire
Mahan, studied gestational diabetes in Boston
and published in Diabetes the first stratifications of the altered glucose metabolism, as
this Irish-born internist wanted to predict
who would become diabetic in the next 20
years. He was less focused on gestational risks
of macrosomia, shoulder dystocia, third and
fourth degree perineal lacerations, increased
Cesarean delivery and increased pregnancy
related hypertension. He was an early public
health pioneer.

For the average pregnancy, the usual time
to screen for gestational diabetes is between
24 and 28 weeks gestation. Those women
with prior macrosomia infants (birth weight
of 4000 grams or 8 pounds 13 ounces), prior
gestational diabetes, glucosuria, obesity (body
mass index (BMI) of 30 or more," or strong
family history of diabetes (either parent or
more than one grandparent and/or sibling)
should be screened at their first or second
visit and rescreened at the 24 to 28-week
timing if they pass the first screen.
There are several ways to screen for gestational diabetes and differing standards for
classification. The one-step screen is used
almost universally except in the United
States. The one-step consists of a fasting blood
glucose, followed by administration of a 75gram Glucola load, and measuring 1 and/or
2-hour blood glucoses with any one or more
values of or above 92, 180 and 150 mg/dL,
resulting in diagnosis of gestational diabetes.
In the two-step process, which O'Sullivan
used, a 50-gram Glucola load was given
regardless of timing of last food intake. For
those ladies with a blood glucose of 130,
135 or 140 mg/dL or more after Glucola
ingestion (dependent on your chosen cutoff),
the next step is a three-hour glucose tolerance

test (GTT) with fasting blood glucose level,
followed by ingestion of 100 grams Glucola,
and blood glucose draws at 1, 2 and 3 hours.
For the GTT to indicate gestational diabetes,
two values must be abnormal.

I am suggesting several changes to the
way we do diabetic identification and care
in pregnancy. First, I would adopt the onestep 75-gram Glucola where the woman
comes to the office or laboratory fasting,
and then is administered her Glucola load
with 1 and 2-hour blood sugars. This is the
standard in virtually every other country. It
would also eliminate the patients' confusion
regarding more than one episode of Glucola
administration. Office staff spend many
hours contacting patients and arranging for
the three-hour testing. I would emphasize
to the patient that she will have only three
venipunctures instead of five venipunctures,
and one-half the total Glucola loads that
the two-step protocol dictates. There is also
the benefit of earlier determination of gestational diabetes or its absence in one clinical
encounter rather than two sessions. For those
ladies who decline to come in fasting for
the one-step and will need to have the less
efficient two-step, I would use a 130mg/dL
cutoff and for the three hours would use the
Carpenter-Coustan stricter standards.

Dietary counsel is the bedrock of good
diabetes care - in or apart from pregnancy.
The Carpenter-Coustan criteria for gestational
diabetes mellitus are 95, 180, 155 and
140 while National Diabetes Data Group
(NDDG) use 105, 190, 165 and 145 for their
fasting, 1, 2 and 3-hour values. I attended the
NIH Consensus Conference on Gestational
Diabetes where the panel selected the less strict
NDDG for many wrong reasons - they were
concerned that there could be a tripling of the
diagnosis of gestational diabetes. My question
is why this would be undesirable, as we could
protect this pregnancy and simultaneously get
a look into her future - an opportunity the
male of the species does not get. The panel
was concerned about excessive testing when a
well-controlled gestational diabetic does not
require extra testing. The biweekly nonstress
tests (NST) and deepest vertical pockets
(DVP) by ultrasound are not indicated in
Why would I use the stricter standards?
the well-controlled gestational diabetic and There is good evidence to suggest less preshould not be reimbursed by insurers.
eclampsia and gestational hypertension in
those identified by the stricter (lower) levels
For the woman with gestational diabetes, to make diagnosis of gestational diabetes.
she gets nutritional counsel as the cornerstone Second, it is important for further glucose
of care. In my years as a practicing obstetrician, testing postpartum to be certain the diabetes
one of my frustrations was the inability to has resolved as a small percentage do not
get dietary counsel for the obese gravida as and need further attention. Third, there
pregnancy is a time when most ladies are is rising evidence of more type 2 diabetes
willing to change eating habits and most likely mellitus in offspring and more autism in
the eating habits of the family. Identifying those children. Fourth, communication to
more ladies as gestational diabetics will get the women regarding gestational diabetes and its
dietary counsel denied by virtually all insurers implications for particularly when combined
currently. Avoiding excess weight gain in the with obesity are critical for her health. As
pregnancy and avoiding retention of excess physicians and citizens, we all need to use
weight are keys to better maternal health the information in our records to delay and
throughout her life cycle. The terminology prevent disease when and wherever we can.
"diabesity" points out the fact that the rising Let's be strict in our care and identify these
incidence of diabetes with rising body mass women so we can foster healthier families
index (BMI) the planet is seeing as a whole is and a healthier nation.
a real phenomenon. For the woman who has
a normal BMI (18.5-24.9) after gestational
diabetes, her diabetes risk in 8-10 years is
15% whereas those gestational diabetics with
BMI >30 have a risk of 75%.

Central PA Medicine Summer 2018 23

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