SUMMARY:

ACOG addresses the management of pregnant women with pregestational diabetes, including specific guidance for the multiple aspects of care. SMFM has provided a sample of an open access checklist in a Special Statement that can be found in ‘Learn More – Primary Sources’.

• Diet
• Insulin
• Hypoglycemia
• Fetal Monitoring and Delivery
• Maternal Morbidity
• Diabetic Ketoacidosis
• Perinatal Morbidity and Mortality

Diet

• Careful carbohydrate counting is the preferred dietary approach to glycemic control (Level B – limited or inconsistent scientific evidence)
  • If possible, a registered dietician or certified diabetes educator should be included in the team
• Advised diet
  • 40-50% complex, high-fiber carbohydrates
  • 15-30% protein
  • 20-35% unsaturated fats
• Typical carbohydrate breakdown
  • Breakfast: 30-45 grams
  • Lunch and Dinner: 45-60 grams
  • Snacks: 15 gram snacks every 2-3 hours
  • Artificial sweeteners may be safely used in pregnancy although research data is limited

Insulin

• Insulin: Preferred agent for treatment of non-diet/ exercise-controlled diabetes
  • Oral hypoglycemic agents should be limited and individualized pending additional safety and efficacy data (Level B)
• Insulin requirements will increase during pregnancy (especially 28-32 weeks)
  • 1st  trimester: 0.7-0.8 u/kg actual body weight/day
  • 2nd trimester: 0.8-1.0 u/kg actual body weight/day
  • 3rd trimester: and 0.9-1.2 u/kg actual body weight/day
• Glucose goals
  • Fasting and premeal: ≤95 mg/dL
  • One-hour postprandial: ≤140 mg/dL
  • Two-hours postprandial: ≤120 mg/dL
  • During the night: Levels should be maintained ≥60 mg/dL
  • Mean capillary glucose: Average of 100 mg/dL
  • HgA_1c (2nd and 3rd trimester): <6% has lowest risk for LGA
• Short or Rapid-acting insulin analogues
  • Lispro and aspart: Preferred short-acting agents
    • Can administer before meals
    • Better compliance | Glycemic control | Overall fewer hypoglycemic episodes
  • Note: Not interchangeable with regular insulin
    • Regular insulin should be administered 10-15 minutes before meal
  • Longer acting insulin: NPH | glargine | detemir
    • Used to maintain euglycemia between meals and fasting
    • Morning dose: Give with rapid-acting insulin before breakfast
    • Evening dose: Ideally at bedtime because injection with supper increases risk of nocturnal hypoglycemia
• Self-monitoring and glucose logs
  • Multiple approaches to self-monitoring
  • Common approach: Capillary levels using glucose meter
    • Fasting | 1 or 2 hours after eating | Before bed
    • Use premeal levels if that is the basis for insulin dosing
    • Nocturnal: 2 to 3 AM of nocturnal hypoglycemia is an issue, especially for those women on pumps
  • Review every 1-2 weeks during the first two trimesters, and every week after 24-28 weeks

Insulin During Delivery

• Bedtime dose: Usual dose of intermediate or long-acting insulin
• Morning dose: Withhold or reduce depending on timing of induction/delivery
• Begin IV normal saline
• Active Labor or glucose <70 mg/dL
  • Switch saline to 5% dextrose: 100-150 cc/hr
  • Maintain glucose level at 100 mg/dL
  • Check glucose hourly (bedside) and adjust insulin/glucose accordingly
  • IV regular insulin: 1.25 units/h if glucose >100 mg/dL

Hypoglycemia (<60 mg/dL)

• Nocturnal hypoglycemia may be caused by
  • Inadequate bedtime snack | Excess basal insulin | Pump malfunction
• Treatment of hypoglycemia
  • 15 grams carbohydrates: Glucose tablets | Milk | Juice
  • Re-check their glucose level after 15 minutes
• All diabetic patients should
  • Have glucagon readily available
  • Wear a medical alert bracelet indicating diabetes

Fetal Monitoring and Delivery

• Ultrasound
  • Fetal viability
  • Fetal anatomy especially cardiac structures
  • Echocardiography: Consider if
    • Suspicion for cardiac anomalies
    • Poor visualization of cardiac structures on routine sono
    • Depending on availability, some practices will refer for the above vs routinely offer fetal echo
• Antenatal fetal monitoring
  • BPP, NST, or modified BPP
  • Once or twice weekly (Level B)
• Macrosomia
  • Consider cesarean delivery for EFW ≥4500 grams (Level C – expert opinion)
  • Women with pregestational diabetes are at increased risk for shoulder dystocia
  • ACOG states

Judicious use of operative vaginal delivery is reasonable even in the presence of risk factors for shoulder dystocia 

• Timing of delivery
  • Diabetic complications: Deliver between 36w0d to 38w6d
    • Vasculopathy | Nephropathy | Poor glycemic control | Prior IUFD
  • Well-controlled: Expectant management until 39th week
    • Requires reassuring antenatal testing
  • Note: Expectant management after 40w0d weeks is not recommended
• Insulin management during labor and delivery
  • Usual dose of intermediate or long-acting insulin given at bedtime
  • IV infusion with saline
    • Change to 5% dextrose if glucose level drops below 70 mg/dL
  • Active labor: Target hourly blood glucose <110 mg/dL
  • Monitor blood glucose levels hourly and adjust infusion of short-acting insulin (insulin drip) accordingly

SYNOPSIS:

Insulin resistance increases during pregnancy to its highest level in the 3^rd trimester, except for late 1^st trimester when high levels of estrogen enhance insulin sensitivity and increase risk of maternal hypoglycemia. Maternal mortality from DKA is rare, and fetal mortality has decreased substantially in recent years.

KEY POINTS:

• Patients and families should be educated on timely diagnosis and treatment of hypoglycemia (Level B)
• Preconception counseling of women with pregestational diabetes should be encouraged as it is cost-effective and beneficial (Level B)
• Baby aspirin (81 mg) supplementation is recommended
  • Reduce associated risk of preeclampsia
  • Preeclampsia is seen in 15-20% of diabetic women without nephropathy, and 50% of those with nephropathy
  • Optimal benefit seen if aspirin started <16 weeks (Level B)
• Concern for diabetic ketoacidosis (DKA) is warranted if a pregnant woman’s glucose levels are >200 mg/dL
  • Check urine ketones and report positive result to provider

Maternal Morbidity

Pregnancy may exacerbate diabetes-related complications

• Retinopathy
  • May progress during pregnancy
  • Obtain comprehensive eye exam early in pregnancy with further monitoring at physician’s discretion based on results
• Diabetic nephropathy (5 to 10% of diabetic pregnancies)
  • Obtain baseline renal function labs prior to or early in pregnancy
  • Progression to end-stage renal disease may occur with serum creatinine >1.5 mg/dL or >3 grams proteinuria/24 hours
• Acute myocardial infarction
  • Obtain a baseline ECG especially with long-standing disease

Diabetic Ketoacidosis (DKA)

• Occurs in 5-10% of all diabetic pregnancies
• Risk factors
  • New onset diabetes | Infection | Poor compliance | Pump failure | *Steroids | Beta-mimetic tocolysis
  • Note: May occur in women with type 2 Diabetes as well as type 1 pregestational diabetes | African Americans appear to be more at risk for DKA in the setting of type 2 diabetes
• Presentation
  • Abdominal pain | Nausea | Vomiting | Altered mental status | Arterial pH <7.3 | Serum bicarbonate <15 mEq/L | Elevated anion gap | Positive serum ketones
• Treatment
  • Aggressive hydration
  • IV insulin (no advantage to lispro or aspart vs regular insulin)
• Labs
  • Arterial blood gases | Glucose | Ketones | Electrolytes (1-2 hour intervals)

*Corticosteroids: ACOG states

…if corticosteroids are administered to accelerate lung maturation in the setting of an obstetric complication, an increased insulin requirement during the next 5 days should be anticipated, and the patient’s glucose levels should be closely monitored. 

Perinatal Morbidity and Mortality

• Major congenital abnormalities
  • Leading cause of perinatal mortality in diabetic pregnancies (6-12%)
  • HgA1c of ≥10% is associated with 20-25% risk for congenital abnormality
• Poorly controlled diabetes is associated with increased risk of stillbirth and fetal weight above 4000 grams
• Women with Type 2 diabetes have similar risks for perinatal mortality as those with Type 1 diabetes
• Women with diabetes have higher risk for
  • Cesarean | Preterm labor | Preeclampsia

Learn More – Primary Sources:

ACOG Practice Bulletin 201: Pregestational Diabetes Mellitus

SMFM Special Statement: Updated checklist for antepartum care of pregestational diabetes mellitus

Related ObG Topics:

Metformin in Pregnancy

Multiple Injections or Continuous Insulin Infusion for Type 1 Diabetes Mellitus in Pregnancy?

Macrosomia: Determination of EFW and Recommendations for Delivery

Do Insulin Analogues Affect Birth Defect Risk Compared to Human Insulin?

CONCEPTT Study: Time for Continuous Glucose Monitoring for All Pregnant Women with Type 1 Diabetes?

Gestational Diabetes Mellitus: Screening and Management