Diabetes in Pregnancy — Gestational & Pregestational Diabetes
Gestational diabetes mellitus (GDM) is glucose intolerance first recognised in pregnancy; in India it affects roughly 10–20% of pregnant women, among the highest rates in the world
Pregestational (overt) diabetes, type 1 or type 2, carries higher risks: congenital anomalies, miscarriage, stillbirth, pre-eclampsia, and diabetic ketoacidosis
Maternal hyperglycaemia causes fetal hyperinsulinaemia, leading to macrosomia, shoulder dystocia, neonatal hypoglycaemia, and later obesity and diabetes
Good glucose control, timely delivery, and postpartum testing prevent most complications and detect future type 2 diabetes
| Test | Threshold | Notes |
|---|---|---|
| Overt diabetes in early pregnancy | Fasting plasma glucose ≥ 126 mg/dL, HbA1c ≥ 6.5%, random glucose ≥ 200 mg/dL with symptoms, or 2-hour OGTT ≥ 200 | Treat as pregestational diabetes; confirm with a repeat test if no symptoms |
| 75 g OGTT (IADPSG / WHO 2013), after overnight fast | Fasting ≥ 92, 1 hour ≥ 180, or 2 hours ≥ 153 mg/dL — any one value makes the diagnosis | Done at 24–28 weeks, or earlier in high-risk women |
| Two-step test (ACOG) | 50 g glucose challenge ≥ 130–140 mg/dL, then 100 g OGTT (Carpenter-Coustan: 95, 180, 155, 140) | Two or more abnormal values diagnose GDM |
| HbA1c | Not used to diagnose GDM; useful in early pregnancy for overt diabetes | Falls physiologically in pregnancy |
Universal testing of all pregnant women, with a single-step 75 g OGTT (Oral Glucose Tolerance Test) given regardless of fasting status or the last meal
Test 1 at the first antenatal contact; Test 2 at 24–28 weeks if the first is negative, at least 4 weeks apart; a woman first seen after 28 weeks gets one test
Diagnosis: 2-hour plasma glucose ≥ 140 mg/dL (read on a plasma-calibrated glucometer); if she vomits within 30 minutes, repeat the next day or refer
Who does it: the ANM (Auxiliary Nurse Midwife) at the village health and nutrition day or sub-centre; the ASHA (Accredited Social Health Activist) mobilises women and follows up
| Topic | Advice |
|---|---|
| First step | Medical nutrition therapy and 30 minutes of walking daily; review after 2 weeks with a 2-hour post-meal glucose |
| Meals | 3 small meals and 2–3 snacks; complex carbohydrates, fibre (pulses, oats), enough protein (about 23 g extra a day); saturated fat under 10% of calories |
| Calories | Pre-pregnancy needs plus about 350 kcal/day in the second and third trimesters; moderate restriction only in obese women — avoid severe restriction (ketosis) |
| Indian targets | Fasting below 95 mg/dL and 2-hour after meals below 120 mg/dL |
| International targets (ADA, American Diabetes Association) | Fasting below 95, 1 hour below 140, 2 hours below 120 mg/dL; HbA1c about 6–6.5% if safe |
| Self-monitoring | Fasting and after meals; on insulin, check fasting and 2-hour post-meal every 3rd day (Indian guideline) or four times a day in pregestational diabetes |
| Drug | Use in pregnancy | Details |
|---|---|---|
| Insulin | First-line in GDM and essential in type 1 and most type 2 | Indian GDM guideline: human premixed 30:70 insulin 30 minutes before breakfast; start 4 units for 2-hour glucose 120–160, 6 for 160–200, 8 for above 200 mg/dL; add 2 units before dinner if fasting is high |
| Basal-bolus insulin | Type 1 and type 2, or GDM needing intensive control | Doses rise through pregnancy (2–3 times by term) and fall sharply after delivery |
| Metformin | After 20 weeks if diet fails, or if insulin is not acceptable | 500 mg twice daily, up to 2 g a day (Indian guideline); crosses the placenta; add insulin if control is inadequate |
| Glibenclamide (glyburide) | Not recommended by many guidelines | Higher risk of neonatal hypoglycaemia and macrosomia; not in the Indian guideline |
| Aspirin | 75–150 mg nightly from 12 weeks in pregestational diabetes | Lowers pre-eclampsia risk |
| Antihypertensives | Switch ACE inhibitors and ARBs before conception | Labetalol or nifedipine are used instead |
| Statins | Stop when planning pregnancy | Not advised in pregnancy |
| Phase | Action |
|---|---|
| Preconception | HbA1c below 6.5% (ideally below 7% before trying); folic acid 5 mg daily; stop statins, ACE inhibitors and ARBs; switch oral agents to metformin or insulin; effective contraception until control is reached |
| First trimester | Check HbA1c, retinal screening (at booking and again at 16–20 weeks), kidney function, urine protein, thyroid function; watch for hypoglycaemia and vomiting with ketosis |
| Anomaly scan | Detailed scan at 18–22 weeks with fetal echocardiography (cardiac defects and neural tube defects are more common) |
| Later pregnancy | Growth scans every 4 weeks from 28 weeks; aspirin and blood pressure checks; antenatal steroids with extra glucose monitoring |
| Complications | Retinopathy may worsen; nephropathy raises pre-eclampsia and growth restriction; DKA risk |
| Topic | Recommendation |
|---|---|
| Ultrasound (Indian guideline) | Anomaly scan at 18–20 weeks if diagnosed before 20 weeks; growth and liquor scans at 28–30 weeks and again at 34–36 weeks, at least 3 weeks apart |
| Fetal movements | 10 kicks within 2 hours after a meal, lying on her side; report the same day if fewer |
| Visits | High-risk schedule: at least monthly, more often with poor control |
| Timing — well-controlled GDM | Deliver at a facility; induce at or after 39 weeks if not in spontaneous labour; routine delivery before 39 weeks is not advised (Indian guideline) |
| Timing — poor control, insulin above 20 units a day, or complications | Refer at 34–36 weeks to a CEmOC centre (Comprehensive Emergency Obstetric and Newborn Care) with a gynaecologist; individualise delivery timing |
| Timing — pregestational diabetes | Usually induction at 37–39 weeks (earlier with vascular disease or poor control) |
| Mode | Vaginal birth preferred; consider caesarean section if the estimated fetal weight is over 4 kg (Indian guideline) — 4.5 kg in some guidelines |
| Antenatal steroids | Dexamethasone 6 mg IM every 12 hours for 2 doses at 24–34 weeks if early delivery is expected; monitor glucose for 72 hours and adjust insulin |
| Stage | What to do |
|---|---|
| Intrapartum | Glucose every hour (every 2 hours in the Indian guideline); hold the morning insulin or metformin; saline at 100 mL/h with regular insulin per 500 mL: 0 units (glucose 90–120), 4 units (120–140), 6 units (140–180), 8 units (above 180 mg/dL); aim to keep glucose about 70–110 mg/dL (international targets) |
| Newborn | Skin-to-skin contact and early breastfeeding; check glucose within 1 hour, then every 4 hours before feeds until 4 stable readings |
| Neonatal hypoglycaemia | Below 45 mg/dL (below 54 in growth-restricted babies): feed and recheck in 1 hour; below 20 mg/dL or symptoms: 10% dextrose 2 mL/kg IV, then infusion; refer to a paediatric centre if it persists |
| Insulin after birth | GDM: stop all drugs and check fasting and 2-hour post-meal glucose; type 1: reduce to the pre-pregnancy dose or lower; type 2: restart metformin (compatible with breastfeeding) |
| Postpartum test | 75 g OGTT at 6 weeks (Indian guideline; 4–12 weeks internationally); fasting ≥ 126 or 2-hour ≥ 200 mg/dL: diabetes; 2-hour 140–199: impaired glucose tolerance |
| Long-term | Yearly screening through the NCD (non-communicable disease) clinic; up to 50% develop type 2 diabetes within 10–20 years; lifestyle change, contraception and pregnancy planning |
Fasting glucose above 200 mg/dL (with or without treatment), or above 150 mg/dL, or after-meal glucose above 250 mg/dL, despite medication
After-meal glucose above 200 mg/dL at any time, or insulin above 20 units a day
Hypoglycaemia more than once a day, refusal of insulin, or vomiting with inability to eat
Warning signs: reduced fetal movements, premature rupture of membranes, abdominal pain, burning micturition, or fever
Level of care: Medical Officer at the PHC starts metformin or insulin; district hospital and CEmOC centres manage all complicated cases
Testing only at 24–28 weeks and missing overt diabetes in early pregnancy
Delaying insulin or using strict calorie restriction that causes ketosis
Forgetting folic acid 5 mg, aspirin, and eye and kidney checks in pregestational diabetes
Missing neonatal glucose checks and postpartum testing; lost follow-up is common
Not reducing insulin after birth — a fall in requirement can cause severe hypoglycaemia
No comments:
Post a Comment