Gestational Diabetes

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Gestational Diabetes

• By Lisa Tang, MD
• August 10, 2005

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Case Presentation

• Mrs. N.M. is 24 y.o. G1P0 overweight woman at 8
  wks by LMP who recently found out she was
  pregnant, presented to the ED with two weeks hx
  of polydipsia and polyuria.
• Random blood sugar was 239. UA noted for 3
  glucose. Pt was discharged from the ED and
  arranged to have follow up for prenatal visit.

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Case Presentation-cont

• PMH
• None
• Meds
• None
• Allergies
• NKDA
• FH
• No FH of DM

• SH
• From Mexico, has been in the U.S. x 6 yrs
• Unplanned but desired pregnancy
• FOB in Mexico
• Good social support -lives with her parents
• High school education
• Used to smoke, 1 pack/wk x 3 yrs, quitted in 7/04
  
• Denies EtOH, and drugs

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Gestational Diabetes (GDM)Epidemiology

• Diabetes Mellitus
• Complicates 3-5 of all pregnancies.
• Affects more than 200,000 women in the U.S. per
  year.
• Is a major cause of perinatal morbidity and
  mortality as well as maternal morbidity.

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Gestational Diabetes (GDM)Epidemiology-cont

• GDM
• Represents approximately 90 of all cases of
  diabetes.
• Is especially common in populations with a higher
  rate of type 2 DM
• -African Americans
• -Asian Americans
• -Hispanic Americans
• -Native Americans

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Definition

• CHO intolerance of variable severity that begins
  or is first recognized during pregnancy. (1)
• Applies regardless of whether insulin is used for
  treatment or the condition persists after
  pregnancy. (1)
• Does not exclude the possibility that
  unrecognized glucose intolerance may have
  antedated the pregnancy. (1)

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Modified Whites Classification of Diabetes in
Pregnancy (6)

• Class A
• Abnormal GTT at any age or of any duration
  treated only by diet therapy

• A1
• -Diet Controlled GDM
• A2
• -Insulin-treated GDM

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Pathophysiology

• Caused by placental production of human placental
  lactogen (HPL) and progesterone.
• Other hormones that may contribute include
  prolactin and cortisol.

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Pathophysiology-cont

• Early in pregnancy, relatively higher levels of
  estrogen enhance insulin sensitivity.
• As placenta develops, estrogen decreases as HPL
  and progesterone rise, resulting in increased
  insulin resistance at the end organs.
• Insulin resistance is most marked in the third
  trimester at which time GDM most often occurs.

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Pathophysiology-cont

• Insulin
• is the major fetal growth hormone .
• produces excessive fetal growth particularly in
  fat, the most insulin-sensitive tissue.

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Growth Abnormalities(1)Two Extremes Of Growth
Abn
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Early Complications

• Congenital malformations in infants of mothers
  with chronic DM (1)
• Leading cause of perinatal mortality in
  pregnancies complicated by DM occurring in 6-12
  of all infants
• Result of poor glucose control during the
  critical weeks of organogenesis, 5-8 wks of
  gestation

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Infant of a Diabetic Mother with Sacral Agenesis

• Cardiovascular anomalies ASD, VSD
• Skeletal anomalies sacral agenesis
• CNS anomalies
• Genitourinary anomalies renal agenesis,
  polycystic kidneys

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Late Complications

• The fetus is likely
• to weigh gt 4000 gram and be disproportionately
  large with increased risk of shoulder dystocia.
• to be at greater risk of intrauterine fetal death
  during the last 4-6 weeks of gestation.
• to be at higher risk of respiratory distress
  syndrome.

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Screening

• Controversial whether all patients should be
  screened for GDM.
• The U.S. Preventive Services Task Force
  concludes that the evidence is insufficient to
  recommend for or against universal screening for
  GDM screening for high risk women may be
  beneficial. (2)
• The American Diabetes Association has proposed
  that screening be limited to women with RF for
  GDM.

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Screening-cont

• Women (at low risk) with ALL of the following
  characteristics need not be screened with a
  laboratory blood glucose test.
• Less than 25 years of age
• Normal body weight with BMI lt 25
• No first degree relative with DM
• Not a member of an ethnic group at increased risk
  for type 2 DM women of Hispanic, African, Native
  American, South or East Asian or Pacific Islands
  ancestry
• No hx of abnormal glucose metabolism
• No hx of poor obstetric outcome

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Screening-cont

• For women who do not meet the above criteria,
  screening should be conducted at 24 -28 wks of
  gestation with use of a 50 g one hour oral
  glucose load
• An abnormal one hour screening test with a venous
  plasma glucose of gt140 mg/dL necessitates a full
  diagnostic 100 g three hours oral glucose
  tolerance test (GTT)

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Screening-cont

• Women at high risk for GDM have the following
  characteristics
• Personal past hx of GDM
• A strong FH of type 2 DM
• Marked obesity
• They should be tested as soon as possible and if
  initial screen is negative, be retested at 24-28
  wks of gestation.

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Dx of GDM with Use of a 100 gram Oral Glucose
Load
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Management

• The goal is to prevent adverse pregnancy
  outcomes.
• A multidisciplinary approach is used.
• Patient is seen every 1-2 wks until 36 wks
  gestation and then weekly.
• Patient is asked to keep an accurate diary of
  their blood glucose concentration.

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Dietary Therapy

• Refer to a dietitian
• Recommend a complex, high fiber CHO diet
• Avoid concentrated sweets

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When Dietary Therapy Fails

• Insulin
• Oral Hypoglycemic Agents
• -Glyburide
• -Metformin

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Insulin Regimen

• Pt should check their fasting glucose and a 1
  hour or 2 hour postprandial glucose level after
  each meal, for a total of four determinations
  each day.
• If the fasting value is gt 95 mg/dL, or 1 hr value
  gt 130-140 mg/dL or 2 hr value gt 120 mg/dL,
  insulin therapy needs to be initiated.

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Insulin Regimen
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Alternative to Insulin TherapyGlyburide

• 2nd generation sulfonylurea
• Does not cross the placenta
• Some physicians are using glyburide in lieu of
  insulin given its ease of use.
• Both the ACOG and ADA do not endorse the use of
  glyburide in the tx of GDM until additional RCTs
  support its safety and effectiveness.

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Alternative to Insulin TherapyMetformin

• Is used as a tx for infertility in PCOS.
• Is a category B drug
• Hasnt been well studied for use in pregnancy.
• Both the ACOG and ADA do not endorse the use of
  metformin in the tx of GDM until additional RCTs
  support its safety and effectiveness.

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Antepartum Testing

• First trimester u/s and a fetal echo to assess
  congenital cardiac anomalies.
• Second trimester u/s to assess fetal growth.

• Twice weekly testing NSTs and amniotic fluid
  volume determination beginning at 32 wks
  gestation to assess fetal well-being.

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Delivery

• Early delivery may be indicated for
• women with poor glycemic control
• pregnancies complicated by fetal abnormalities
• Otherwise, pregnancies are allowed to go to term.

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Intrapartum

• The goal is to maintain normoglycemia in order to
  prevent neonatal hypoglycemia.
• Check patients glucose q1-2 hours.
• Start insulin drip to maintain a glucose level of
  between 80 - 110 mg/dL.
• Observe infant closely for hypoglycemia,
  hypocalcemia, and hyperbilirubinemia after birth.

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Postpartum Care

• After delivery
• Measure blood glucose.
• -fasting blood glucose concentrations should
  be lt105 mg/dL and one hour postprandial
  concentrations should be lt 140 mg/dL.
• Administer one half of the pre-delivery dose
  before starting regular food intake.

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Postpartum Care-cont

• Follow up
• Per American Diabetes Association, a 75 g two
  hours oral GTT should be performed 6-8 wks after
  delivery.

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Postpartum Care-cont

• Follow up
• If the pts postpartum GTT is normal, she should
  be re-evaluated at a minimum of 3 years interval
  with a fasting glucose.
• All pts should be encouraged to exercise and lose
  wt.
• All pts should be evaluated for glucose
  intolerance or DM before a subsequent pregnancy.

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Management of Mrs. N.M

• First Trimester
• Ht 60 inches
• Current Wt 179 lbs Pre-pregnancy Wt 155 lbs
• Routine prenatal labs wnl
• HgbA1C 8.8
• 19 wks u/s normal, with EDD 5/13/2005
• Fetal echo was done at 20 wks with BPD and FL c/w
  stated GA. No obvious structural or functional
  fetal heart dz.

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Management of Mrs. N.M-cont

• Initial prenatal visits issues addressed
• Diabetic teaching-including how to use a
  glucometer and how to inject insulin. Pt was
  educated about the signs of hypoglycemia and was
  told to eat small snacks if that happen.
• Self monitoring and diet modification
• Exercise pt began to walk daily x 30 mins

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Management of Mrs. N.M-cont

• Second Trimester
• Level II U/S was done. Result was normal with a
  single IUP, posterior placenta and no e/v of
  placenta previa. SizeDate
• Insulin regimen consisted of NPH and Lispro was
  initiated.
• HgbA1C 5.0

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Management of Mrs. N.M-cont

• Third Trimester
• Biweekly antenatal testing began.
• Insulin regimen was adjusted according to
  increased needs.
• HgbA1c 5.3
• Two more u/s were done with normal fetal growth.

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Delivery

• Pt had NSVD on 5/7/2005 at 39 wks of gestation.
• She delivered a healthy boy, B.M. with wt 2895 g
  (6 lb 6 oz) and Apgar 8, 9.
• Delivery was complicated by 1st deg lac.
• Blood sugar was monitored q2 and insulin drip per
  protocol was used.

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Postpartum

• Insulin regimen was decreased to ½ of her
  previous regimen.
• Given that Mrs. N.M.s RF and elevated HgbA1c at
  presentation, she most likely has pre-existing DM
  Type II.

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Now

• On metformin 500 mg po daily the first week, then
  BID after
• Mrs. N.M. is breastfeeding.
• Her mother has been helping her out with child
  care.
• Baby boy, B.M. is growing appropriately and
  meeting all his developmental milestones.

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Take Home Message

• As obesity increases in the U.S., the rate of
  gestational diabetes will rise.
• All pregnant women should be screened for GDM,
  whether by pts hx, clinical risk factors, or a
  lab screening test to determine blood glucose
  levels. (3)
• It is important that multidisciplinary approach
  be used to improve pregnancy outcome.

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Questions?
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Bibliography

• Gabbe, Steven MD and Graves, Cornelia R MD,
  Management of Diabetes Mellitus Complicating
  Pregnancy, Obstetrics Gynecology
  2003102(4)857-868
• Turk, David K MD, MPH, Ratcliffe, Stephen D, MD,
  and Baxley, Elizabeth G. MD, Management of
  Gestational Diabetes Mellitus, Am Fam Physician
  2003681767-72,1775-6
• ACOG Practice Bulletin No 30 Gestational
  Diabetes. Volume 98 No 3 September 2001
• Jovanovic, Lois MD, Screening and Diagnosis of
  Gestational Diabetes Mellitus, Up to Date version
  13.2
• Jovanovic, Lois MD, Treatment and Course of
  Gestational Diabetes Mellitus, Up to Date version
  13.2
• Barss, Vanessa MD and Blatman, Robert N. MD,
  Obstetrical Management of Pregnancy Complicated
  by Diabetes Mellitus, Up to Date version 13.2
• USPSTF Guidelines Screening for Gestational
  Diabetes Recommendations and Rationale
• ADA Position Statement Gestational Diabetes
  Mellitus