questions 7

Gestational Diabetes

Topic updated on 06/08/17 6:14pm

  • A 33-year-old G3P2 female is at 25 weeks gestation. Fundal height measures 31 cm. Obstetric ultrasound reveals four quadrant amniotic fluid index (AFI) of 30 cm. An ultrasound is performed. 
  • Glucose intolerance or diabetes mellitus (DM) first recognized during pregnancy
  • Occurs in 2-5% of all pregnancies
    • #1 medical complication of pregnancy
  • Caused by placental-released human placental lactogen (HPL) which antagonizes insulin
    • worsens with pregnancy as placenta enlarges and more HPL is released
  • Risk factors include
    • previous history of gestational diabetes mellitus (GDM)
    • obesity
    • history of prior abortions or stillbirths
    • family history of DM
    • maternal age > 30
  • Asymptomatic
  • At 24 - 28 weeks
    • check fasting plasma glucose
      • if greater than 125 mg/dL, suspect diabetes mellitus
      • < 95 mg/dL considered normal 
    • administer a 1 hour 50 g oral glucose tolerance test (Glucola)
      • if blood glucose > 140 mg/dL at 1 hour, suspect gestational diabetes
      • this is a very sensitive test (a negative test rules it out)
    • confirm with a 3 hour 100 g oral glucose tolerance test; abnormal measurements are:
      • > 180 mg/dL at 1 hour
      • > 155 mg/dL at 2 hours
      • > 140 mg/dL at 3 hours
      • this is a very specific test (a positive test rules it in)
  • Strict adherence to ADA diet and glucose control
  • If diet is insufficient to control administer insulin
  • Oral hypoglycemic medications can be used
    • metformin is currently approved for usage during pregnancy
    • glyburide is also considered safe
    • in general insulin is a better answer for step exams
  • Delivery
    • determined by estimated fetal weight
    • if 4000-4500 g, consider a caesarian section
Prognosis, Prevention, and Complications
  • 95% return to normal postpartum
    • glucose screen 2 months postpartum to confirm
  • Maternal complications include
    • type II DM later on in life (50%)
    • 2X risk of pregnancy induced hypertension, preeclampsia, eclampia
    • polyhydraminos (> 2000 mL)
      • caused by polyuria of the fetus
    • hyperglycemia
    • increased risk of UTIs
    • pre-term labor
    • retinopathy
    • caesarian secondary to macrosomia
    • no increased risk of spontaneous abortion if well controlled
  • Fetal complications include
    • perinatal mortality (2-5%)
    • abruption and preterm labor
    • 3X congenital malformations
      • limb deformities
      • neural tube
      • cardiac deformities 
        • secondary to trophic effect of insulin
      • macrosomia (> 4500 g)
        • shoulder dystocia during vaginal delivery 
    • neonatal hypoglycemia
      • due to abrupt separation from high maternal glucose supply with a large amount of fetal insulin present
      • ß-cell hyperplasia in the newborn leading to hypoglycemia
    • hyperbilirubinemia
    • polycythemia
    • respiratory distress syndrome (RDS)


Qbank (4 Questions)

(M2.OB.18) A 25-week pregnant woman comes to your office for a regular prenatal visit. She had no history of diabetes prior to this pregnancy. Among other tests, you perform a fasting glucose test for which she has exceeded the upper limit of normal. What is the fasting blood sugar cutoff required to warrant further testing for gestational diabetes? Topic Review Topic

1. 85 mg/dL
2. 95 mg/dL
3. 105 mg/dL
4. 115 mg/dL
5. 126 mg/dL

(M2.OB.80) An obese, 32-year-old G3P2A0L2 woman presents to her obstetrician for follow-up at week 26 of her pregnancy. She previously had a random plasma glucose during her pregnancy of 140 mg/dL. One hour after a 75 g oral glucose load, the patient's plasma glucose level is 200 mg/dL. Which of the following is a potential complication of her diagnosis? Topic Review Topic

1. Post-term birth due to fetal macrosomia
2. Neonatal hyperglycemia
3. Type I diabetes after completion of her pregnancy
4. Type II diabetes after completion of her pregnancy
5. Down syndrome in the infant

(M2.OB.252) A 31-year-old G2P1 female at 27 weeks gestation presents to your clinic for prenatal care. Past medical history is insignificant and she takes no medications except for prenatal vitamins. Following administration of 50 grams of glucose, the patient's plasma glucose after one hour is 165 mg/dL. A subsequent 3-hour oral glucose tolerance test is positive for gestational diabetes. Which of these neonatal outcomes is most commonly associated with gestational diabetes? Topic Review Topic

1. Intrauterine growth restriction (IUGR)
2. Situs inversus
3. Shoulder dystocia
4. Neural tube defects
5. Cardiovascular defects

(M2.OB.4752) A 31-year-old G1P0000 presents to the obstetric service for a scheduled induction of labor at 39 weeks due to poorly controlled gestational diabetes. Her pregnancy was largely uncomplicated aside from abnormal 1-hour and 3-hour glucose tolerance tests, for which diet and lifestyle management were initially recommended. Due to poor glycemic control despite these interventions, the patient was started on insulin. Postprandial glucose levels were in the 170-180 mg/dL range throughout the remainder of her pregnancy. She has a family history of diabetes in her mother and grandmother, as well as hypertension in her father and preeclampsia in her sister. The patient had an appropriate weight gain of 26 pounds during this pregnancy, with a pre-pregnancy BMI of 22.4 kg/m^2. At her last ultrasound one month ago, the estimated fetal weight was 4,100 g, and upon arrival on the labor floor, the updated measurement is 4,560 g. The patient continues to desire a vaginal delivery and is subsequently induced. After 24 hours, the infant’s head delivers but the shoulders do not. The mother’s hips are flexed and pressure is applied to the suprapubic region without improvement, and internal rotation is ultimately required to deliver a male infant after 3 minutes. One hour after delivery, the infant is found to have an absent Moro reflex on the left side. He is shown in Figure A. Which of the following would have most likely prevented this infant’s presentation? Topic Review Topic
FIGURES: A          

1. Operative vaginal delivery
2. Administration of magnesium sulfate during delivery
3. Decreased caloric intake by the mother during pregnancy
4. Intensive glycemic control in the mother during pregnancy
5. Episiotomy at time of delivery

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