🩺 MedAtlax

Search

SearchSearch

Diabetes in pregnancy

Sep 14, 20256 min read

Diabetes & Pregnancy

DR RAYAN ALBARAKATI

GDM Definition:

Glucose intolerance with onset first recognition during pregnancy

Varieties:

  • Preexisting DM
  • GDM (A1 & A2)

Introduction

Most common medical complication of Pregnancy

3-8 % of pregnancies

  • GDM 90% - (half develop DM after pregnancy)
  • Preexisting DM 10%

Physiological changes during pregnancy

  • Pregnancy is a state of insulin resistance & relative glucose intolerance
  • This is due to placental production of anti-insulin hormones : hPL, cortisol, and glucagon
  • FBS might be low (increased insulin sensitivity in 1st trimester) and increased glucose uptake
  • Postprandial glucose increased
  • Insulin increases by 2 folds in N women
  • Insulin requirements increased (fetal growth)
  • ↓ Renal threshold for glucose glycosuria (Increased GFR, tubular reabsorption is less efficient)

EFFECT OF PREGNANCY ON pt with DM

Insulin requirement increased reaching a max at term & being about 2 X the pre-pregnancy requirement

Pt with diabetic nephropathy:

  • Deterioration in renal function
  • Proteinuria.
  • Usually reversed after delivery

EFFECT OF PREGNANCY ON DM

  • 2 X increase in retinopathy

  • Hypoglycemia (with tight control of BG level)

  • Ketoacidosis: rare unless associated with hyperemesis, infections, tocolytics & corticosteroid Rx

  • Increased risk of PIH especially in pt. with pre-existing hypertension & nephropathy

  • Postpartum hemorrhage … why ? *

    (placentomegaly - polyhydramnios- macrosomic baby)

EFFECTS OF DM ON PREGNANCY

Increased risk of abortions

  • increased incidence of congenital abnormalities
  • 5% with Hb A1c > 8
  • 25% with Hb A1c > 10
  • Sacral agenesis, congenital heart defects, skeletal abnormalities & neural tube defects - (most common congenital heart diseases;)
  • Perinatal & neonatal mortality increased 2-4 X
  • Unexplained IUFD at term (more in macrosomic babies)

NTD: Spina Bifida

Caudal regression

AKA sacral agenesis

EFFECTS OF DM ON PREGNANCY

Macrosomia >4000g

  • Risk increased with poor diabetic control
  • Not eliminated by tight control
  • Increased risk of operative delivery, birth trauma, & shoulder dystocia

Hyperglycemia: fetal polyuria - polyhydramnios -PROM - PTD

Delayed lung maturity

Prematurity

EFFECTS OF DM ON PREGNANCY- Postnatallyy

infant is at risk of:

  • Hypoglycemia
  • hypotension (low glucose and low Ca & Mg)
  • Electrolytes imbalance (↓ Ca++, ↓ Mg++)
  • Polycythemia causing hyperviscosity & jaundice β€” why ? hypoxia

Preexisting Diabetes:

  • Preconception Counselling
  • risk of NTD ~1-2% (
  • Folic Acid 1-4 mg /day
  • BG 3.5-5.3 prior to meals
  • switch /adjust insulin +/- OHA

GDM High Risk Factors

  • Maternal age >25
  • Family history
  • Glucosuria
  • Prior macrosomia
  • Previous unexplained stillbirth
  • PCOS
  • ethnic group: Hispanic, Asians, Black

Screening

  • 24-28 weeks routine
  • screen at 1st prenatal visit if high risk
  • 50 g GCT at 1 hour (don’t need to fast prior to test)
  • β‰₯ 130 mg/dl β†’ OGTT
  • β‰₯ 200mg/dl β†’ No further tests & start treatment.
  • Diagnostic test β†’ 3-hour 100g OGTT

Values on 100g OGTT

#TimingMax Normal Blood Glucose level (mg/dL)
0Fasting95
11 hr180
22 hr155
33 hr140
  • 2 or more abnormal readings is diagnostic for GDM

Maternal Risks

  • Increased birth trauma
  • Operative delivery **
  • 50% lifetime risk in developing Type II DM
  • recurrence risk of GDM is 30-50%
  • Cesarean section if baby wt. β‰₯ 4250-4500 g

Fetal Risks

  • Increase in congenital anomalies
  • increased risk of stillbirth
  • Macrosomia
  • Birth trauma (shoulder dystocia)

Management

  • Goal is to optimize BG levels
  • Minimize risk of adverse perinatal outcomes
  • diet +/- OHA
  • exercise
  • insulin therapy

Diet : general principles

Composition:

  • 50% CHO
  • 20% Protein
  • 20% fat

Total calories to be divided :

  • 25% breakfast
  • 30% Lunch
  • 30% Dinner
  • 15% at bedtime snack

Calories intake

  • BMI>27 β†’ 25 kcal/kg/ideal body weight/d
  • BMI 20-26 β†’ 30 kcal/kg/ideal body weight/d
  • BMI<20 β†’ 38 kcal/kg/ideal body weight/d

Normal weight gain 10-12 kg Exercise : Walking 30 min after meals

Insulin

Types:

  • Rapid (Lispro) 30-90 min
  • short acting (regular) 2-3 hours
  • Long acting (NPH) 6-10 hours

Dosage calculation & timings:

  • depends on: (Body weight, Trimester)
  • Divided doses (AM - PM)
  • How & what insulin to mix ?

OHA

  • Types :

    • Glyburide
    • Metformin
      • Both safe in pregnancy
      • Both to be used prior to meals (30-60 min)
      • Both cross the placenta
      • Both can be used with diet alone or combined with insulin

  • Effects:

    • Lower mean birth Wt.
    • Less macrosomia
    • Less Gestational Wt. gain
    • Treatment failure between 15 -30%

Glyburide

  • Starting dose of 2.5 to 5 mg once daily
  • Increased as needed up to 20 mg/Day in divided doses
  • Higher risk of hypoglycemia than insulin

Metformin

  • Starting dose 500mg with dinner

  • can be increased to 1000 mg with dinner or 500 mg with dinner and breakfast

  • Usual effective dose 1500-2000 mg daily divided into two doses

  • Maximum daily dose is 2500 mg.

  • Extended Release (XR) form is preferred over the regular type

  • Not recommended to be used in patients with Htn., PET, or at risk of IUGR or pt. with Renal disease

Insulin Dosage calculation

  • Insulin units = body weight (kg)
  • Γ—0.6 (First trimester)
  • Γ—0.7 (Second trimester)
  • Γ—0.8 (Third trimester)
  • Dosage schedule: give 2/3 in AM and 1/3 in PM
  • Before breakfast: 2/3 NPH, 1/3 regular or lispro
  • Before dinner: 1/2 NPH, 1/2 regular or lispro (if on lispro, administer additional dose before bedtime snack)

#RR Controller gastric secretory release insulin

Insulin Total dose Calculation

Total Insulin units = Body Wt. (Kg) Γ— Trimester

  • Body Wt. (Kg)
  • Trimester
    • 1st β†’ 0.6
    • 2nd β†’ 0.7
    • 3rd β†’ 0.8

Total Insulin units is divided into:

  • AM: 2/3rd
  • PM: 1/3rd

What & how to mix INSULIN?

  • AM dose: 2/3rd NPH and 1/3rd Lispro or Regular

  • PM dose: Β½ NPH and Β½ Lispro or regular

Insulin Type & Total dose distribution

  • Total Insulin units
    • AM
      • 2/3rd
      • (2/3rd NPH and 1/3rd Lispro or Regular Ins)
    • PM
      • 1/3rd
      • (Β½ NPH and Β½ Lispro or regular)

Timing of Delivery

GDM Diet controlled

  • Same as nondiabetic
  • IOL at 40 - 41 weeks if undelivered

GDM on Insulin/Type II/Type I

  1. Well controlled β†’ Deliver by 38+ to 39 weeks
  2. Suboptimal control β†’ deliver following confirmation of lung maturity

Mode of Delivery :

  • Vaginal delivery is recommended
  • c/s for maternal or fetal indications
  • Ultrasound estimates of fetal weight become significantly inaccurate after 4kg
  • High risk for shoulder dystocia
  • C/S delivery if EFW is >4250g

Peripartum/Intrapartum Management

  • Withhold subcutaneous insulin from onset of labor or induction
  • IV D10 @50cc/h
  • insulin in NS usually starting at 0.5-1u/h insulin rate usually based on BG and pre-delivery insulin requirement
  • BG hourly
  • target: 4-6mmol/L

Postpartum

GDM:

  • D/C insulin
  • 6 - 12 weeks postpartum 75g OGTT
  • Yearly fasting BG
  • Advise for weight control & exercise
  • With breastfeeding mothers add 500 kcal/day for the pregnancy diet
  • Life risk of developing DM-II is 50%

Pre-pregnancy DM:

  • stop insulin infusion
  • Begin subcutaneous insulin
  • Resume previous schedule at 1/2 -2/3 the pre-pregnancy dose
  • Maintain IV D5W @50cc/h until oral feeds tolerated
  • Refer to MD outpatient for follow-up.

Graph View

Backlinks