DIABETES MELLITUS IN PREGNANCY

Associate Professor Dr Hanifullah Khan

Definition

A metabolic condition characterized by chronic hyperglycemia as a result of defective insulin

secretion, insulin action or both

Classification

1. Type 1(IDDM)

2. Type 2(NIDDM)

3. Gestational diabetes

4. Others -genetic defects in insulin processing or action

-endocrinopathies

-drugs

-exocrine pancreatic defects

-genetic syndromes associated with dm

Diabetes in pregnancy

• Glucose intolerance of variable severity with onset or first identification during the pregnancy– Constitutes 90 percent of diabetes in pregnancy

– Generally occurs in the latter half of pregnancy

– Usually no effect on organogenesis (no congenital defects)

– Disappears after delivery

• Either type 1 or type 2

• Type 1 – younger age group

– increased maternal and obs risks

• Type 2 – usually occurs in obese patients

Pregnancy as a diabetogenic state

• glucose is made available to the fetus– ↑ placental hormones such as estrogens, progesterone,

PRL, hPL– ↑ plasma cortisol– A state of insulin resistance– Further aggravated by ↑ body weight and ↑ caloric

intake during pregnancy

• GDM develops when the pancreas cannot overcome the effect of these hormones

• Pregestational diabetes becomes worse during pregnancy

Risk factors - history

• Age>30 years

• Previous GDM

• Family history of DM

• Bad Obs history

• History of macrosomia

• Prev. fetal anomalies

• History of unexplained stillbirth

Associated clinical factors

• Congenital fetal anomalies

• Pre-eclampsia

• Obesity > 90 kg

• Recurrent UTI, vaginal candidiasis

• Presence of glycosuria on more than 2 occasions

April 11, 2023GDM 9

Screening for diabetes

• GDM is asymptomaticasymptomatic

• Screening test needed– OGTT

• Either – Universal screening

– Selective screening (based on risk factors)

Selective screening

Selective screening-oral glucose tolerance test 75 grams of oral glucose is given 3 readings -fasting glucose level, 1 hr and 2 hr post glucose The diagnosis of dm is made when fasting glucose level are

≥7.8 and or 2 hour level of >11.1 If the 2 hours levels are between 7.8 and 11.1,the patient is

said to have impaired glucose tolerance test and should be treated as gdm.

April 11, 2023GDM 11

Screening algorithm

• Policy of screening only if one of a number of risk factor is indicated as follows

– BMI >27kg/m2

– Previous macrosomic baby weighing 4kg or above– Previous gestational diabetes mellitus (GDM)– First-degree relative with diabetes– Fetal anomalies– Glycosuria at the first prenatal visit– Current obstetric problems (essential hypertension, pregnancy

induced hypertension, polyhydramnios and current use of steroids)– Age above 35– Unexplained IUD– Recurrent miscarriage– Multiple pregnancy

Risk Factors

Maternal complications - pregnancy

1. Pre-eclampsia

2. Recurrent infection-vaginal candidiasis,uti

3. Polyhydramnios—pprom, cord prolapse,

4. Increased instrumental and CS rates

5. Anomalies & abortions

6. Sudden IUD

7. Post-delivery, 40-60% of women develop type 2 DM within 10 years

Maternal complications - medical

1. Retinopathy

2. Nephropathy

3. Neuropathy

4. Micro/macroangiopathy

Fetal complications

1. Congenital anomalies (4 fold) - sacral agenesis, NTD, cardiac and renal anomalies

2. Macrosomia

3. Respiratory distress syndrome

4. Hypoglycemia-result of hyperplasia of beta cell

5. Prematurity

6. Malpresentation

7. Shoulder dystocia

8. Polycythemic -jaundice

Macrosomia

Mechanism of Macrosomia

Shoulder dystocia

Blood Investigation

1. Blood sugar level-weekly assessment is required. Useful in deciding whether to start insulin or adjusting insulin dosage

2. HbA1c-done in first trimester. It gives retrospective assessment 12 weeks ago. High HbA1c at the end of first trimester indicates sugar control was poor during organogenesis period.

3. Maternal serum AFP-done between 16 to 20 weeks pog

Urine

• Urine microscopy and culture-to exclude UTI (bacteriuria)

Imaging Investigations

• Diagnostic imaging-gestational age, fetal abnormities, fetal growth, liquor volume.

• Doppler of umbilical artery-done in cases of diabetic vasculopathy

Investigation

1. Blood sugar level-weekly assessment is required. Useful in deciding whether to start insulin or adjusting insulin dosage

2. Urine microscopy and culture-to exclude uti(bacteriuria)

3. HbA1c-done in first trimester. It gives retrospective assessment 12 weeks ago. High HbA1c at the end of first trimester indicates sugar control was poor during organogenesis period.

4. Maternal serum AFP-done between 16 to 20 weeks pog

Investigations

5. Diagnostic imaging-gestational age, fetal abnormities, fetal growth, liquor volume.

6. Doppler of umbilical artery-done in cases of diabetic vasculopathy

Management-

The key to successful management in diabetic pregnancy is early diagnosis which allows treatment to be started early.

• Antenatal management – Plasma glucose level should be maintained between 4-6 mmol/L– Early dating and scan to exclude fetal abnormalities– Diet control should be attempted first. If failure insulin should be started.– Admission-poor blood sugar control, PIH, polyhydramnios. BSP should be

monitored

– Fetal growth chart

• Timing for delivery-if on insulin,38 weeks, if on diet control, can prolonged to term

• Mode of delivery-LSCS if macrosomia baby,malpresentation,evidence of fetal compromise

– Check BP– Monitor closely with continuous CTG

Treatment

Oral hypoglycemic drugs are generally not recommended as it can cause teratogenic effect towards fetus and can cross placenta causing hypoglycemia

• Diet therapy– Total calories advised is 24-30 kcal/kg of the present body weight.In

obese diabetic pt. 24kcal/kg is advised– The calories should be distributed between 3 meals and 3 snacks– Dietary control decrease postprandial glucose level and it also improve

insulin action.– Blood glucose level and weight gain can be used to formulate a meal plan

Exercise

• Exercise– Light exercise help by lowering fatty acid

– Contracting muscle help stimulate glucose transport hence decrease blood sugar

– Better done after meals

– Exercise involving the muscle of upper part of the body is sufficient to lower down glucose level.

Insulin

• Insulin regimes– 15% required insulin therapy

– Insulin is indicated in all pregestational diabetes and poorly controlled gdm

– The popular regimes use a mixture of short acting and medium acting insulin

Pre-pregnancy counselling

• This play an important roles for pregestational diabetes in order to prevent early pregnancy loss and congenital anomalies.

• Complete assessment of diabetic status should be done to find out whether she is fit to go through pregnancy. HbA1c can be done to evaluate blood glucose control 12 weeks ago.

• Those with oral hypoglycemic should be switched to insulin therapy.

The rule of 15 for GDM

• 15% of pt. with positive gct will have gdm

• 15% percent of GDM will required insulin

• 15% of GDM will have macrosomia

• 15% of GDM will have impaired gtt after delivery