Gestational diabetes is a type of diabetes that develops during pregnancy in women who have never had diabetes before. It occurs in about 5% of all pregnancies. If not treated, gestational diabetes can cause health problems for both the mother and fetus, such as delivering a large baby. Risk factors include maternal age over 25, family history of diabetes, and belonging to certain ethnic groups. Women are screened for gestational diabetes between 24-28 weeks of pregnancy through a glucose challenge test and glucose tolerance test if needed. Treatment may involve diet, exercise, blood sugar monitoring, and possibly insulin.

1. GESTATIONAL
DIABETES
Prepared by dr.kucha

5. Gestational Diabetes
This diagnosis is given when a woman, who
has never had diabetes before, gets
diabetes or has high blood sugar, when she
is pregnant.
Its medical name is gestational diabetes
mellitus or GDM.
It is one of the most common health
problems for pregnant women.
The word “gestational” actually refers to
“during pregnancy.”
5 of 42 gdm

6. As the incidence of type 2 diabetes
accrues with age and is unmasked by
other diabetogenic factors, that is,
obesity, it is likely that both
pregnancy aggravation and
impending insulinopenia are
involved.

7. CHO Metabolism
Effects of Pregnancy
*Mild fasting hypoglycemia;
*Post prandial hyperglycemia
Due to increase in plasma volume in early
gestation and increase in fetal glucose
utilization.
As pregnancy advances -Progressive
increase in tissue resistance to insulin
– Increase insulin secretion to maintain
euglycemia
– Suppressed glucagon response
– Inc. prolactin, cortisol
– HPL has GH like effects

8. ‘Endocrinology of Pregnancy’
The placenta produces larger
quantities of more hormones than
any other human organ:
– Human placental lactogen
– Estrogen / progesterone
The majority of its products are
released into the maternal circulation
to induce changes on the fetuses’
behalf.

9. Glucose Metabolism in Pregnancy
Fetal growth is dependent upon
maternal glucose
Carbohydrates from maternal diet
Stored glycogen converted to
glucose
High levels of glucose transported by
diffusion to the fetus
Fetal production of insulin

10. Glucose Metabolism in Pregnancy
First Half of Pregnancy (Anabolic)
– Pancreatic beta-cell hyperplasia causes
hyperinsulinemia
– Increased uptake and storage of glucose
Second Half of Pregnancy (Catabolic)
– Placental hormones block glucose receptors
and cause insulin resistance
Increased lipolysis
Increased gluconeogenesis
Decreased glycogenesis
– Increased glucose and amino acids for the
fetus

11. Pedersen Hypothesis (1952)
Maternal hyperglycemia 
Fetal hyperglycemia 
Fetal hyperinsulinemia 
Excess fetal fat

13. Maternal and Fetal Effects
The American College of Obstetricians and
Gynecologists (2000) defines macrosomic infants
as those whose birthweight exceeds 4500 g.
The perinatal goal is avoidance of difficult
delivery due to macrosomia, with concomitant
birth trauma associated with shoulder dystocia.
Except for the brain, most fetal organs are
affected by the macrosomia that commonly
characterizes the fetus of a diabetic woman.

14. Neonates born from women with consistently
high blood sugar levels are also at an increased
risk of low blood glucose
(hypoglycemia), jaundice, high red blood
cell mass (polycythemia) and low blood calcium
(hypocalcemia) and magnesium
(hypomagnesemia).
Untreated GDM also interferes with maturation,
causing dysmature babies prone to respiratory
distress syndrome due to incomplete lung
maturation and impaired surfactant synthesis.

15. The most important perinatal concern is
excessive fetal growth, which may result
in both maternal and fetal birth trauma.
More than half of women with gestational
diabetes ultimately develop overt diabetes
in the ensuing 20 years, and there is
mounting evidence for long-range
complications that include obesity and
diabetes in their offspring.

16. There is extensive evidence that
insulin-like growth factors I (IGF-I)
and II (IGF-II) also play a role in the
regulation of fetal growth (see Chap.
38, Normal Fetal Growth). These
growth factors, which structurally are
proinsulin-like polypeptides, are
produced by virtually all fetal organs
and are potent stimulators of cell
differentiation and division

17. Maternal hyperglycemia prompts
fetal hyperinsulinemia particularly
during the second half of gestation,
which in turn stimulates excessive
somatic growth. Macrosomia results.
Similarly, neonatal hyperinsulinemia
may provoke hypoglycemia within
minutes of birth

18. Other factors implicated in
macrosomia include epidermal
growth factor, leptin, and
adiponectin
Maternal obesity is an independent
and more important risk factor for
large infants in women with
gestational diabetes than is glucose
intolerance

19. Gestational Diabetes
It occurs in about 5% of
all pregnancies.
If not treated,
gestational diabetes
can cause health
problems for the
mother and the fetus.
kvr gdm

20. Gestational Diabetes
Risk Factors
maternal age >25
Family history
glucosuria
prior macrosomia
previous unexplained stillbirth
ethnic group: Hispanic, Black,
Asians

21. Screening
Screening should be performed between
24 and 28 weeks in those women not
known to have glucose intolerance earlier
in pregnancy.
This evaluation is usually done in two
steps. In the two-step procedure, a 50-g
oral glucose challenge test is followed by a
diagnostic 100-g oral glucose tolerance
test (OGTT) if initial results exceed a
predetermined plasma glucose
concentration.

22. Fifth International Workshop-Conference on Gestational
Diabetes: Recommended Screening Strategy Based on
Risk Assessment for Detecting Gestational Diabetes
(GDM)
GDM risk assessment: Should be ascertained at
the first prenatal visit
Low Risk: Blood glucose testing not routinely required if all the
following are present:
Member of an ethnic group with a low prevalence of GDM
No known diabetes in first-degree relatives
Age < 25 years
Weight normal before pregnancy
Weight normal at birth
No history of abnormal glucose metabolism
No history of poor obstetrical outcome

23. Average Risk
Perform blood glucose testing at 24 to 28 weeks
using either:
—Two-step procedure: 50-g oral glucose challenge
test (GCT), followed by a diagnostic 100-g oral
glucose tolerance test for those meeting the
threshold value in the GCT.
—One–step procedure: Diagnostic 100-g oral
glucose tolerance test performed on all subjects.

24. High Risk:
Perform blood glucose testing as soon as feasible,
using the procedures described above if one or
more of these are present:
—Severe obesity
—Strong family history of type 2 diabetes
—Previous history of GDM, impaired glucose
metabolism, or glucosuria. If GDM is not diagnosed,
blood glucose testing should be repeated at 24 to
28 weeks or at any time there are symptoms or
signs suggestive of hyperglycemia

25. Diagnosis
Recommended criteria for interpretation of
the 100-g diagnostic glucose tolerance
test are shown in Table 52-4. Also shown
are the criteria for the 75-g test most
often used outside the United States, but
increasingly used in this country

27. Management
Women with gestational diabetes can
be divided into two functional classes
using fasting glucose levels. Insulin
therapy is usually recommended
when standard dietary management
does not consistently maintain the
fasting plasma glucose at < 95
mg/dL or the 2-hour postprandial
plasma glucose < 120 mg/dL

28. Whether insulin should be used in women with
lesser degrees of fasting hyperglycemia—105
mg/dL or less before dietary intervention—is
unclear because there have been no controlled
trials to identify ideal glycemia targets for
prevention of fetal risks.
The Fifth International Workshop Conference on
Gestational Diabetes, however, recommended
that maternal capillary glucose levels be kept 95
mg/dL in the fasting state

29. The American Diabetes Association (ADA) (2000) has
recommended nutritional counseling with individualization
based on height and weight and a diet that provides an
average of 30 kcal/kg/d based on prepregnant body weight
for nonobese women.
Although the most appropriate diet for women with
gestational diabetes has not been established, the ADA has
suggested that obese women with a body mass index (BMI)
> 30 kg/m2 may benefit from a 30-percent caloric
restriction. This should be monitored with weekly tests for
ketonuria, because maternal ketonemia has been linked
with impaired psychomotor development in offspring

30. Exercise
exercise is known to be important in nonpregnant
patients
exercise improves cardiorespiratory fitness
without improving pregnancy outcome.
physical activity during pregnancy reduced the
risk of gestational diabetes.
exercise diminishes the need for insulin therapy
in overweight women with gestational diabetes.

31. researchers' findings support the common
practice of self blood-glucose monitors for women
with gestational diabetes who are treated with
diet alone.
Postprandial surveillance for gestational diabetes
has been shown to be superior to preprandial
surveillance

32. Insulin
Insulin given to decrease
complications related to macrosomia
in women with gestational diabetes
and fasting euglycemia has long
been controversial

33. Most initiate insulin therapy in women with gestational diabetes if
fasting glucose levels exceeding 105 mg/dL persist despite diet
therapy.
Experts differ in their approach to insulin therapy in gestational
diabetes. A total dose of 20 to 30 units given once daily, before
breakfast, is commonly used to initiate therapy.
The total dose is usually divided into two-thirds intermediate-
acting insulin and a third short-acting insulin.
Alternatively, weight-based split-dose insulin is administered twice
daily. Once therapy has been initiated, it must be recognized that
the level of glycemic control to reduce fetal and neonatal
complications has not been established.

34. Oral Hypoglycemic Agents
The American College of
Obstetricians and Gynecologists
(2001) has not recommended these
agents during pregnancy.
Metformin has been used as
treatment for polycystic ovarian
disease and has been reported to
reduce the incidence of gestational
diabetes in women who use the drug
throughout pregnancy

35. Insulin Treatment
Insulin is used for overtly diabetic pregnant
women. Although oral hypoglycemic agents have
been used successfully for gestational diabetes
(Oral Hypoglycemic Agents), these agents are not
currently recommended for overt diabetes except
on an investigational basis (American College of
Obstetricians and Gynecologists, 2005). Maternal
glycemic control can usually be achieved with
multiple daily insulin injections and adjustment of
dietary intake. The action profiles of commonly
used insulins are shown in Table 52-10

37. It is important to considerably reduce or delete
the dose of long-acting insulin given on the day
of delivery. Regular insulin should be used to
meet most or all of the insulin needs of the
mother at this time, because insulin requirements
typically drop markedly after delivery. We have
found that continuous insulin infusion by
calibrated pump is most satisfactory (Table 52-
13).

38. During labor and after delivery, the woman
should be adequately hydrated intravenously and
given glucose in sufficient amounts to maintain
normoglycemia. Capillary or plasma glucose
levels should be checked frequently, and regular
insulin should be administered accordingly. It is
not unusual for a woman to require virtually no
insulin for the first 24 hours or so postpartum
and then for insulin requirements to fluctuate
markedly during the next few days. Infection
must be promptly detected and treated.

40. Table 52-5. Glyburide Treatment Regimen for
Women with Gestational Diabetes Who Fail Diet
Therapy
1. Glucometer blood glucose measurements fasting and 1 or
2 hours following breakfast, lunch, and dinner.
2. Glucose level goals (mg/dL): Fasting < 100, 1-h < 155,
and 2-h < 130.
3. Glyburide starting dose 2.5 mg orally with morning meal.
4. If necessary, increase daily glyburide dose by 2.5-mg/wk
increments until 10 mg/d, then switch to twice-daily
dosing until maximum of 20 mg/d reached. Switch to
insulin if 20 mg/d does not achieve glucose goals.

41. Postpartum Evaluation
The Fifth International Workshop Conference on
Gestational Diabetes recommended that women
diagnosed with gestational diabetes undergo
evaluation with a 75-g oral glucose tolerance test
at 6 to 12 weeks postpartum and other intervals
thereafter (Metzger and associates, 2007). These
recommendations are shown in Table 52-6 along
with the classification scheme of the American
Diabetes Association (2003).

43. Women with a history of gestational diabetes are also at risk for
cardiovascular complications associated with dyslipidemia,
hypertension, and abdominal obesity—the metabolic syndrome
(see Chap. 43, The Metabolic Syndrome).
Akinci and associates (2009) reported that a fasting glucose level
100 mg/dL with the index OGTT was an independent predictor of
the metabolic syndrome.

44. Contraception
Low-dose hormonal contraceptives
may be used safely by women with
recent gestational diabetes . The rate
of subsequent diabetes in oral
contraceptive users is not
significantly different from that in
those who did not use hormonal
contraception

45. References
Adasheck JA, Lagrew DC, Iriye BK, et al: The influence of ultrasound examination at
term on the rate of cesarean section. Am J Obstet Gynecol 174:328, 1996
Akinci B, Celtik A, Yener S, et al: Prediction of developing metabolic syndrome after
gestational diabetes mellitus. Fertil Steril January 13, 2009 [Epub ahead of print]
Albert TJ, Landon MB, Wheller JJ, et al: Prenatal detection of fetal anomalies in
pregnancies complicated by insulin-dependent diabetes mellitus. Am J Obstet Gynecol
174:1424, 1996 [PMID: 9065106]
Almario CV, Ecker T, Moroz LA, et al: Obstetricians seldom provide postpartum
diabetes screening for women with gestational diabetes. Am J Obstet Gynecol
198:528.e1, 2008

46. American College of Obstetricians and Gynecologists: Gestational diabetes.
Practice Bulletin No. 30, September 2001
American College of Obstetricians and Gynecologists: Pregestational diabetes
mellitus. Practice Bulletin No. 60, March 2005
American Diabetes Association: Medical Management of Pregnancy Complicated
by Diabetes, 2nd ed. Jovanovic-Peterson L (ed). Alexandria, VA, American
Diabetes Association, 1995
American Diabetes Association: Clinical practice recommendations, 1999.
Diabetes Care 23:S10, 1999a
American Diabetes Association: Report of the Expert Committee on the
Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 22:512, 1999b