Synopsis
Coordinate preconception, antenatal, intrapartum and postnatal diabetes care to reduce maternal, fetal and neonatal harm while avoiding severe hypoglycaemia and ketoacidosis.
- Pre-existing type 1 or type 2 diabetes and gestational diabetes are distinct pathways, but all need joint obstetric–diabetes care and explicit postpartum planning.
- Offer preconception review before pregnancy where possible: optimise glucose safely, prescribe high-dose folic acid, review medicines, assess retina and kidneys, and discuss pregnancy-specific risks.
- NICE advises aiming for preconception HbA1c below 48 mmol/mol when achievable without problematic hypoglycaemia and strongly advises avoiding pregnancy when HbA1c exceeds 86 mmol/mol.
- Stop ACE inhibitors, angiotensin-receptor blockers and statins before conception or promptly when pregnancy is confirmed; replace them through specialist advice.
- Metformin may be used before and during pregnancy when benefit outweighs harm; other oral glucose-lowering medicines are usually stopped and insulin substituted under the specialist pathway.
- NICE diagnoses gestational diabetes on a 75-g oral glucose tolerance test when fasting plasma glucose is at least 5.6 mmol/L or the 2-hour value is at least 7.8 mmol/L; HbA1c is not the standard later-pregnancy diagnostic test.
- If safely achievable, NICE pregnancy capillary targets are fasting below 5.3 mmol/L and either 1-hour post-meal below 7.8 or 2-hour post-meal below 6.4 mmol/L; people using insulin should keep glucose above 4 mmol/L.
- For gestational diabetes with fasting glucose below 7.0 mmol/L, start diet and exercise; offer metformin if targets are unmet after 1–2 weeks, and offer immediate insulin with or without metformin at 7.0 mmol/L or above.
- Offer real-time continuous glucose monitoring to pregnant people with type 1 diabetes and provide specialist education on sensor limitations, insulin adjustment and ketone testing.
- Gestational diabetes medication usually stops after birth, but persistent hyperglycaemia must be excluded and lifelong type 2 diabetes surveillance arranged.
Key red flags
Nausea, vomiting, abdominal pain, dehydration, deep breathing or malaise with blood ketones can represent DKA even when glucose is not markedly raised, particularly with pump interruption or SGLT2 exposure.
Reduced awareness, nocturnal episodes, seizure or third-party assistance is especially concerning early in type 1 pregnancy. Review targets, insulin, CGM alarms and glucagon access immediately.
New visual symptoms, worsening albuminuria, hypertension or declining renal function may represent pregnancy-accelerated retinopathy, kidney disease or pre-eclampsia and needs joint specialist assessment.
Reduced fetal movement, abnormal growth, polyhydramnios, hypertension, proteinuria or threatened preterm birth changes surveillance and delivery planning; glucose control alone does not determine safety.
Investigation priorities
Quantify recent exposure and identify a safer route into pregnancy.
Management branches
A person with diabetes could become pregnant or is actively planning conception.
- Discuss contraception until ready, pregnancy risks, glucose targets, hypoglycaemia and ketone plans, and refer promptly to the joint diabetes–pregnancy service.
- Start folic acid 5 mg daily through 12 weeks of pregnancy, optimise HbA1c safely and arrange retinal, renal, blood-pressure and medication review.
- Stop or replace ACE inhibitors, ARBs, statins and unsuitable glucose-lowering medicines through authorised prescribers; never withdraw insulin from type 1 diabetes.
- Provide meter or CGM supplies, blood-ketone equipment, glucagon where appropriate and written contacts for positive pregnancy test, vomiting, ketones or severe hypoglycaemia.