Download Highlighting the Differences between Preexisting Type 1 and Type 2

Highlighting the Differences between Preexisting Type 1 and
Type 2 Diabetes in Pregnancy and Gestational Diabetes
Elizabeth (Libby) Downs Quiroga, MS, RD, CDE
Tandem Diabetes Care – Clinical Specialist
Grand Rapids MI
Abstract
Diabetes is the most common
metabolic complication of
pregnancy. Placental hormones,
growth factors, and cytokines can
cause increased insulin resistance.
The different types of diabetes seen
in pregnancy present challenges to
clinicians; each type has different
guidelines for treatment based on
the pathogenesis. Medical nutrition
therapy (MNT) and medication
management are key components to
achieving the goal of normoglycemia.
Understanding the pathogenesis and
classification of diabetes during
pregnancy can help clinicians to
provide appropriate care.
Introduction
Diabetes is the most common
metabolic complication of pregnancy,
and all forms of diabetes can occur
in pregnant women. Diabetes in
pregnancy is characterized by the
time of diagnosis in relationship
to pregnancy (preexisting versus
gestational) and the etiology of beta
cell dysfunction and hyperglycemia
(e.g., immune for type 1 diabetes and
nonimmune with insulin resistance
for type 2 diabetes). Preexisting
diabetes (types 1 and 2) complicates
0.1% to 0.3% of all pregnancies (1).
Gestational diabetes (GDM)
complicates 1% to 14% of all
pregnancies.
Geetha Rao, MS, RD, CDE, CDTC, CPT, CLE
Palo Alto Medical Foundation
Freemont, CA
Characteristics of
Preexisting Diabetes
during Pregnancy
Women who have preexisting diabetes
may experience greater problems with
blood glucose control in pregnancy,
and diet and exercise changes alone
might not successfully compensate for
increased insulin needs. Preexisting
diabetes is primarily treated with insulin
during pregnancy. The progressive
increase in insulin resistance caused by
placental hormones, growth factors,
and cytokines in pregnancy requires
intensive MNT and frequent insulin
dose adjustments to prevent
worsening of complications from
diabetes. Women with preexisting
diabetes have a four- to fivefold
increase in perinatal mortality and a
four- to sixfold increase in stillbirth
compared to the population without
diabetes (2).
Insulin needs vary throughout the
pregnancy. From week 17 and on,
insulin needs start to rise sequentially
until 35 weeks at which point the
needs level off or decline (3). However,
women with type 1 diabetes might
see significantly low glucose values
during gestational weeks 9 through
16 unless they adjust their insulin
doses (4). In contrast, women with
type 2 diabetes may have improved
glucose values during this phase of
pregnancy. Women who live with type
1 diabetes may experience a 60%
to 200% increase in insulin needs
during the second and third
trimesters (3). Those with type 2
diabetes may see insulin doses
double by the middle of the second
trimester and even triple or more by
term (3). Hence, the net change in
insulin resistance and increase in
insulin requirement is less in those
who have type 2 diabetes, but the
final level of insulin resistance and
insulin requirement may be the same
or more than in those who have type
1 diabetes.
The incidence of diabetes ketoacidosis
(DKA) in pregnancy is 1% to 3% of
patients with preexisting diabetes,
and women with type 1 diabetes are
more prone to DKA than those with
gestational or type 2 diabetes (3).
The fetal mortality rate during this
condition is approximately 9% to
35%, and the risk of maternal death is
estimated at 5% to 15% (3). DKA can
occur in pregnancy at blood glucose
levels of less than 200 mg/dL, and
most cases of DKA develop in the
second and third trimester when
insulin needs are rising (3). Accordingly,
insulin should not be withheld for
more than a few hours in a patient
with type 1 diabetes, even if she has
normal blood glucose values, to
prevent the onset of DKA (3). Glucose
and ketones readily cross the
placenta while maternal volume
depletion and acidosis may cause
fetal hypoxia (3).
Hemoglobin A1c (HbA1c) testing for
this population should be addressed
5
before conception. High blood
glucose levels at conception and
during organogenesis increases the
risk of spontaneous abortion and
major congenital malformations.
Hyperglycemia reduces oxygen
supply to the fetus and when
combined with maternal acidosis,
can lead to fetal demise.
Gestational Diabetes
GDM is defined as the onset
of varying degrees of glucose
intolerance during the second or
third trimester that is not clearly
overt diabetes (5). GDM results from
an imbalance between tissue insulin
requirements for glucose regulation
and the ability of the pancreatic beta
cells to meet these requirements.
GDM is typically diagnosed late in
pregnancy (between 24 and 28 weeks
of gestation) and is generally not
associated with the early gestational
age birth defects that can be seen in
babies of mothers with preexisting
diabetes. GDM accounts for
approximately 90% of all cases of
diabetes in pregnancy and is associated
with overweight/obesity, history of
GDM in prior pregnancy, polycystic
ovary syndrome, presence of glucosuria,
family history of diabetes, and certain
ethnic groups (e.g., Asians, African
Americans, and Hispanics). It resolves
in 90% of cases after delivery (6).
Diagnosing Gestational Diabetes
GDM can be diagnosed via one- or
two-step approaches (5):
1. One-step 75-g oral glucose
tolerance test (OGTT)
2. Two-step 50-g (nonfasting)
screen followed by a 100-g OGTT
for those who have positive
screen results
One-step Approach
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The American Diabetes Association
(ADA) recommends that all pregnant
women who are not known to have
Table 1. Plasma Glucose Values Indicating Gestational Diabetes
for the Two-step Strategy Oral Glucose Tolerance Test
Time
Carpenter/Coustan (9)
National Diabetes Data Group (10)
Fasting
95 mg/dL (5.3 mmol/L)
105 mg/dL (5.8 mmol/L)
1 hour
180 mg/dL (10.0 mmol/L)
190 mg/dL (10.6 mmol/L)
2 hours
155 mg/dL (8.6 mmol/L)
165 mg/dL (9.2 mmol/L)
3 hours
140 mg/dL (7.8 mmol/L)
145 mg/dL (8.0 mmol/L)
prior diabetes undergo a 75-g OGTT
at 24 to 28 weeks of gestation, based
on the recommendation of the
International Association of the
Diabetes and Pregnancy Study
Groups (IADPSG) (5,7). The IADPSG
defined diagnostic cut points for
GDM as the average glucose values
(fasting, 1-hour, and 2-hours after
glucose testing) in the Hyperglycemia
and Adverse Outcomes Study (HAPO),
at which odds for adverse outcomes
was 1.75 times the odds of these
outcomes at mean glucose levels
of the study population (5).
For the one-step strategy, the diagnosis
of GDM is made when one glucose
reading is equal to or greater than:
•Fasting glucose: 92 mg/dL
(5.1 mmol/L)
•1-hour glucose: 180 mg/dL
(10.0 mmol/L)
•2-hour glucose: 153 mg/dL
(8.5 mmol/L)
Two-step Approach
In the two-step strategy, a nonfasting
50-g oral glucose challenge test is
administered to women not previously
diagnosed with overt diabetes. If
the 1-hour plasma glucose measures
140 mg/dL (7.8 mmol/L) or greater,
the woman undergoes a 100-g OGTT.
The American College of Obstetricians
and Gynecologists (ACOG)
recommends a lower threshold of
135 mg/dL (7.5 mmol/L) in high-risk
populations that have higher
prevalences of GDM. According to
ACOG, treatment of higher-threshold
maternal hyperglycemia reduces the
risks of neonatal macrosomia, largefor-gestational age births, and
shoulder dystocia without increasing
small-for-gestational age births (8).
The patient must be fasting for the
OGTT. GDM is diagnosed if at least two
of the four plasma glucose level values
(fasting, 1 hour, 2 hours, and 3 hours
after OGTT) are met or exceeded .
There are two sets of OGTT glucose
diagnostic criteria currently in use for
diagnosing GDM; one is by Carpenter
and Coustan (this is the more sensitive
criteria thus will include more
diagnoses of GDM) and the other by
the National Diabetes Data Group
(NDDG) (Table 1).
ACOG updated their guidelines in
2013 to support the two-step
approach (11). The ADA suggests that
a GDM diagnosis can be established
with either of the two strategies.
For a comparison, criteria to diagnose
type 2 diabetes in the first trimester
of pregnancy are:
• F asting blood glucose:
≥126 mg/dL (7.0 mmol/L)
• HbA1c: ≥6.5%
•R
andom plasma glucose:
≥200 mg/dL (11.1 mmol/L)
Monitoring
Patient monitoring during pregnancy
should include daily blood glucose
testing, ketone evaluation, and
HbA1c measurement. An overview of
monitoring for treatment of diabetes
in pregnancy is presented in Table 2.
Blood Glucose Monitoring
Preprandial and postprandial
monitoring of blood glucose is
recommended to achieve metabolic
control in pregnant women with
diabetes (5). ACOG recommends
the following targets for women
with preexisting type 1 or type 2
diabetes (5):
• Fasting: ≤90 mg/dL
• One-hour postprandial:
≤130–140 mg/dL
• Two-hour postprandial:
≤120 mg/dL
Clinicians should note that these
values represent optimal control if
they can be achieved safely. However,
women with type 1 diabetes may
find that achieving these targets
without hypoglycemia is a challenge,
particularly women who have a
history of severe hypoglycemia or
hypoglycemia unawareness (5). If
women cannot achieve these targets
without significant hypoglycemia,
the ADA recommends liberalized
targets that are individualized (5).
The following glucose targets are
recommended by the Fifth
International Workshop-Conference
on Gestational Diabetes Mellitus (5):
• Fasting: ≤95 mg/dL and either
• One-hour postprandial:
≤140 mg/dL or
• Two-hour postprandial:
≤120 mg/dL
Women with preexisting diabetes
should measure their blood glucose
eight to 12 times or more a day and
document food and blood glucose
daily (3). Experts recommend that
those who are diagnosed with GDM
periodically self-monitor or test their
blood glucose (3).
Ketones
Ketones are usually present in normal
pregnancies after a 14-hour fast. The
goal for fasting urinary ketone levels
is none or trace in those with
diabetes during pregnancy. Urine
ketone testing is not routinely
recommended for those who have
GDM unless they are experiencing
persistent weight loss (12).
Urine ketone testing is recommended
for women who have poorly controlled
or newly diagnosed type 1 diabetes.
Urine ketone testing is also
recommended when blood glucose
persistently measures greater than
200 mg/dL in pregnancy complicated
with type 1 diabetes (3). Commonly
reported symptoms of DKA are
gastrointestinal upset such as nausea,
vomiting, poor oral intake, or flu like
symptoms (3). If the registered dietitian
nutritionist has any suspicion of the
presence of DKA, the woman should be
referred to her physician immediately.
Hemoglobin A1C
The ADA recommends maintaining
HbA1c of less than 6% to 6.5% in the
second and third trimesters to avoid
large-for-gestational-age infants and
women with preexisting diabetes.
However, the recommendation states
that a value of less than 6% may be
optimal as the pregnancy progresses
without hypoglycemia to avoid the
risk of low-birth weight infants. If
women cannot achieve these targets
without significant hypoglycemia,
the ADA suggests less stringent
Table 2. Monitoring During Pregnancy
Gestational Diabetes
Type 2 Diabetes
Type 1 Diabetes
Frequency of daily
4
BG testing 4-7 (depending on if patient
is on medications)
7-8
BG goals (mg/dL)
Fasting: ≤95
1-hr PP: ≤140
2-hr PP: ≤120
Fasting: ≤90
1-hr PP: ≤130-140
2-hr PP: ≤120
Fasting: ≤90
1-hr PP: ≤130-140
2-hr PP: ≤120
Hemoglobin
A1c target
A1c may be useful, it should
be used as a secondary
measure, after BG monitoring
6%-6.5% recommended if can be achieved without significant hypoglycemia
6% to 6.5% recommended
if can be achieved without
significant hypoglycemia
1. With start of MNT for
1-2 weeks and if rapid
weight loss occurs
2. Anytime BG is persistently
>200 mg/dL, if moderate
to large, contact health
care provider
1. Anytime BG is persistently
>200 mg/dL, if moderate to
large, contact health care
provider
2. Newly diagnosed
3. Every 4 hours if ill until
ketones cleared
Ketone testing
Test only if persistent weight loss or need to identify if a woman is
consuming adequate calories and/or carbohydrates
BG=blood glucose, MNT=medical nutrition therapy, PP=postprandial
7
targets based on clinical experience
and individualization of care.
Medical Nutrition
Therapy with Diabetes
and Pregnancy
During any pregnancy, energy needs
increase during the second and third
trimesters. Nutrition needs for those
who are overweight or obese are
explored in other articles in this issue
of On The Cutting Edge. However,
moderate caloric restriction (30%33% energy needs) in obese women
with GDM may improve glycemic
control without ketonemia and
reduced weight gain (13) and prevent
macrosomia. The Institute of Medicine
(IOM) recommends the following
estimated energy requirement (EER)
for those ages 19 years and older for
preconception needs (3):
Nonpregnant EER =
354 – (6.91 x age in years) +
Physical Activity (see below) x
[(9.36 x weight in kilograms) +
(726 x height in meters)]
Physical Activity coefficient guide:
Sedentary: 1.0; Low active: 1.12;
Active: 1.27; Very Active: 1.45
The following IOM formulas are for
pregnant women who are of normal
weight:
First trimester:
EER = Nonpregnant EER + 0 kcal
Second trimester:
EER = Nonpregnant EER + 340 kcal
Third trimester:
EER = Nonpregnant EER + 452 kcal
Multifetus pregnancy increases
caloric needs by about 150 kcal/day
over the needs of a singleton
pregnancy (3).
The Recommended Daily Allowance
(RDA) for carbohydrates during
pregnancy is a minimum of
8
175 g/day to provide 33 g/day for
fetal brain development (3). However,
contributions of carbohydrate to
energy intake should be individualized
(3). To address the sensitivity that
many women experience with
carbohydrates, a meal pattern of
three meals plus two to four snacks
daily may help with careful distribution
of carbohydrates and individualization
to preference and tolerance (3).
Because the first meal of the day
(breakfast) is when insulin resistance
is greatest, improved postprandial
glucose management may be
achieved if carbohydrates are more
limited at this meal (3). Helping the
patient with preexisting diabetes,
especially type 1 diabetes,
understand the use of intensive
carbohydrate counting and the
insulin-to-carbohydrate ratio is
essential (3).
benefits beyond simply reducing
postprandial hyperglycemia (3).
Foods that rapidly absorb into the
blood stream (high glycemic index
foods) should not be included in a
GDM meal plan. Examples include:
refined sugars, fruit juices, regular
sodas and sports drinks, highly
processed cereals, and instant
potatoes and noodles. The use of
glycemic index and glycemic load is
controversial but when establishing
an individualized meal plan for a
woman with diabetes, a prudent
approach may be to advise her to use
her blood glucose results to
determine the effect of various foods
on her glucose levels and make
modifications to her food choices as
necessary (3). Of note, avoiding fruit
and milk at breakfast may help
improve glycemic control after that
meal (3).
The RDA for protein requirements
during pregnancy is 71 g/day, but
the preconception protein RDA is
0.8 g/kg/day and requirements do
not increase to 1.1 g/kg/day until
the second half of pregnancy (3).
Inclusion of protein at snacks can
increase satiety (3). Also, inclusion
of protein at the bedtime snack and
waiting no longer than 10 hours
between a bedtime snack and
breakfast may prevent starvation
ketosis (3).
Those with GDM and type 2 diabetes
often have dyslipidemia and a high
risk for cardiovascular disease (CVD)
(3). In general, limiting total fat is a
good recommendation for women at
high risk for CVD. However, limiting
total fat may not be best for patients
with high triglyceride and/or low
high-density lipoprotein values (3).
The goals of MNT for women with
preexisting diabetes are to meet
nutrition needs, achieve appropriate
weight gain, and reduce maternal
and fetal mortality and morbidity.
MNT for women who have GDM is
designed to meet nutrition needs of
mother and fetus while maintaining
normoglycemia and appropriate
weight gain.
For women with GDM, low-glycemic
index foods provide potential
Nutrition education should include
the following, as appropriate:
• Rationale for the meal plan,
including achieving glycemic
control, optimal nutrient intake
throughout pregnancy, and
appropriate weight gain
• Spacing of meals and snacks
to avoid hypoglycemia and
hyperglycemia
• Use of blood glucose values and
food records to problem-solve
and/or identify blood glucose
excursions related to food intake
• The need for medications and
dose adjustments
• The role and timing of exercise to
improve blood glucose levels
• Different methods of
carbohydrate counting and meal
plan flexibility
• Use of non-nutritive sweeteners
• Use of herbs
• Reading of food labels
• Treatment and prevention of
hypoglycemia
• Menu ideas and restaurant
ordering skills
• Handling sick days, hyperemesis,
and carbohydrate replacement
if taking glyburide or insulin
• Long-term healthy eating habits
to avoid type 2 diabetes or its
complications if GDM
Weight Gain
The IOM currently has no specific
weight gain recommendations for
pregnant women with diabetes.
Gestational weight recommendations
are listed in Table 3.
their urinary ketones and adjust
calorie/carbohydrate intake
accordingly (3).
Summary
Different types of diabetes in
pregnancy are associated with
different issues. Managing preexisting
diabetes and GDM can present
significant challenges to both health
care providers and patients.
Understanding the pathogenesis of
each type of diabetes greatly aids in
providing appropriate care. Optimal
care requires attention to nutrition,
maternal glycemia, comorbid
conditions, and patient selfmanagement skills.
References
Some weight loss may follow
initiation of MNT due to diuresis
related to decreased carbohydrate
intake (3). Such fluid loss is often
seen in women with GDM (3). Weight
begins to increase once the fluid
shifts have subsided within 1 to 2
weeks of MNT initiation (3). If weight
loss persists, clinicians may
recommend that patients monitor
1.American Diabetes Association.
Diagnosis and classification of
diabetes mellitus. Diabetes Care.
2011;34(suppl 1):S62–S69.
2.Platt MJ, Stanisstreet M, Casson
IF, et al, St. Vincent’s Declaration:
10 years on: outcomes of diabetic
pregnancies. Diabet Med.
2002;19(3):216–220.
3.Shields L, Tsay GS (eds). California
Diabetes and Pregnancy Program
Sweet Success Guidelines for Care.
Sacramento, CA: California
Department of Public Health;
Table 3. 2009 Institute of Medicine Gestational Weight
Gain Guidelines
Prepregnancy
Total Weight
Body Mass Index
Gain Range (lb)
Mean Rate of Weight Gain in
Second and Third Trimesters
(range in lb/wk)
Underweight28-40
1
<18.5(1-1.3)
Normal Weight
25-35
18.5-24.9
1
(0.8-1)
Overweight15-25
0.6
25.0-29.9 (0.5-0.7)
Obese11-20 0.5
≥30.0(0.4-0.6)
Adapted with permission from Weight Gain During Pregnancy: Re-examining the Guidelines, 2009 by
the National Academy of Sciences, courtesy of the National Academies Press, Washington, DC.
Is it Pregestational or
Preexisting Diabetes?
The 2016 American Diabetes
Association Standards of Care
refer to women with preexisting
type 1 or type 2 diabetes
who are pregnant as having
pregestational diabetes (5).
The American College of
Obstetricians and Gynecologists
refer to women with preexisting
diabetes during pregnancy
(either as type 1 or type 2) as
having preexisting diabetes (9).
On The Cutting Edge authors
prefer to use the term “preexisting
diabetes” when referring to
women with type 1 or type 2
diabetes who become pregnant.
Maternal Child and Adolescent
Health Division; 2015.
4.Garcia-Patterson A, Gich I, Amini
SB, Catalano PM, de Leiva A,
Corcoy R. Insulin requirements
throughout pregnancy in women
with type 1 diabetes mellitus:
three changes of direction.
Diabetologia. 2010;53(3):446–451.
5.American Diabetes Association.
Standards of medical care in
diabetes-2016. Diabetes Care.
2016;39(suppl 1).
6.Jovanovic I. Medical Management
of Pregnancy Complicated by
Diabetes. 3rd ed. Alexandria, VA:
American Diabetes Association;
2000:111–132, 151–157.
7.Metzger BE, Gabbe SG, Persson B,
et al; International Association of
Diabetes and Pregnancy Study
Groups Consensus Panel.
International Association of
Diabetes and Pregnany Study
Group’s recommendations on
the diagnosis and classification
of hyperglycemia in pregnancy.
Diabetes Care. 2010;33(3):676–682.
9
8.Horvath K, Koch K, Jeitler K, et al.
Effects of treatment in women
with gestational diabetes
mellitus: systematic review
and metaanalysis. BMJ. 2010;
340:c1395.
9.Carpenter MW, Couston DR.
Criteria for screening tests for
gestational diabetes. Am J Obstet
Gynecol. 1982;144(7):768–773.
10.National Diabetes Data Group.
Classification and diagnosis of
diabetes mellitus and other
categories of glucose intolerance.
Diabetes. 1979;28(12):1039–1057.
11.Committee on Practice BulletinsObstetrics. Practice Bulletin No.
137: Gestational diabetes
mellitus. Obstet Gynecol.
2013;122(2 pt1):406–416.
12.International Federation of
Clinical Chemistry and The
American Association for Clinical
Chemistry Critical Care and Point
of Care Testing Division. Critical
Care Testing in the New Millennium:
The Integration of Point of Care
Testing. Presented at the 18th
International Symposium,
Helsingor, Denmark. June 1-4,
2000.
13.American Diabetes Association.
Nutrition recommendations and
interventions for diabetes:
A position statement of the
American Diabetes Association.
Diabetes Care. 2007;30(suppl 1):
S48–S65.
14.Rasmussen KM, Yaktine AL,
Editors: Committee to Reexamine
IOM Pregnancy Weight
Guidelines Food and Nutrition
Board, Board on Children, Youth
and Families. National Academies
Press Washington DC; 2009.
10
Preconception and Internatal Nutrition
Recommendations for Women
with Diabetes
Jamie Stang, PhD, MPH, RD
Associate Professor University of Minnesota, School of Public Health
Minneapolis, MN
Abstract
All women want to have healthy
babies, but few women prepare
adequately for pregnancy. Nutrition
programs and services can have
a positive impact on the health
of women before and between
pregnancies, reducing their risk
for poor pregnancy outcomes.
Preconception and internatal
nutrition services for women with
diabetes should focus on: identifying
and treating comorbid conditions
such as hypertension and obesity,
achieving tight blood glucose control
at least 1 to 3 months before
conception, helping women attain
and maintain a healthy body weight
before and between pregnancies,
encouraging consumption of 0.4 to
4 mg of folic acid supplementation
daily for at least 2 to 3 months before
conception, and fostering a dietary
pattern that can reduce the risk of
inflammation and infection.
Introduction
All women want to have healthy
babies, but not all women prepare
for pregnancy to ensure a positive
outcome. Many factors contribute
to the lack of preconception or
internatal (the period of time
following one pregnancy and
preceding another that may also
be referred to as interconception)
planning. In the United States, 51%,
or nearly 3.4 million pregnancies
each year, are unintended (1), and
data suggest that the rate of
unintended pregnancy among
women with diabetes may be
considerably higher, with rates of
up to 66% (2). Thus, little or no
preconception planning occurs in
one-half to two-thirds of pregnancies
among women with diabetes. In
addition, many women are unaware
of the additional risks that chronic
health conditions such as obesity,
diabetes, and hypertension place
upon mother and fetus during
pregnancy. Lack of awareness of
these risk factors before conception
dramatically reduces the window of
opportunity for ameliorating risk.
Addressing
Chronic Conditions
Among Women of
Reproductive Age
One of the most vulnerable periods
of fetal development is the first 14 to
56 days after conception. During this
early developmental period, when
many organs and appendages are
formed, fetuses are susceptible to
congenital anomalies such as neural
tube defects (NTDs) (spina bifida and
anencephaly); limb reduction; and
heart, brain, ear, and eye defects. The
increased risk can result from poor
nutrition status, elevated blood
glucose levels, or exposure to
medications known to cause birth
defects such as statins, angiotensinconverting enzyme inhibitors,
diuretics, beta-blockers, and other
antihypertensive medications (3, 4).
Many women are not aware of their