Type 1 and type 2 diabetes in pregnancy: planning and care

Type 1 diabetes, in which the body no longer makes insulin, and type 2 diabetes, in which the body does not use insulin well, are described on the NHS diabetes page. Gestational diabetes is a separate condition that first appears in pregnancy and usually resolves after the birth, and it has its own guide on this site.

With pre-existing diabetes, high glucose is present from the earliest weeks, when the baby's organs are forming. That is why the focus is on preparation before conception and not just on managing glucose once pregnancy is confirmed.

The NHS lists a higher chance of miscarriage, a larger baby with a more difficult birth, induction or caesarean delivery, and breathing or heart problems in the newborn that may require hospital care. Birth defects, particularly of the heart and nervous system, stillbirth and neonatal death are slightly more likely. Pregnancy can worsen diabetic retinopathy and kidney disease, and women with type 1 diabetes are at risk of diabetic ketoacidosis.

Tommy's adds that careful preparation substantially reduces these dangers. Most of the risks are linked to how high glucose runs, so tighter control is the main lever.

The NHS recommends planning pregnancies where possible, speaking to your GP or diabetes team, and asking for referral to a pre-conception diabetes clinic. Contraception continues until glucose control is where it needs to be.

• HbA1c is checked regularly; a level at or below 48 mmol/mol (6.5%) is the goal if reachable without frequent hypoglycaemia.

• Take 5mg folic acid daily, which needs a prescription, from before conception until 12 weeks. The NHS vitamins page confirms the higher dose for women with diabetes.

• Ask for eye screening within six months and kidney function tests before you stop contraception, as Tommy's advises.

• Review blood pressure tablets, statins and any GLP-1 weight-loss medicine, because some are not safe in pregnancy.

• People with type 1 diabetes should ask about continuous glucose monitoring and, where available, hybrid closed loop systems.

The NHS says women who control diabetes with tablets are usually switched to insulin, with or without metformin, and that those already on insulin may need a different type or dose. Needs change across pregnancy: nausea and vomiting early on can cause low glucose, while insulin resistance rises in later weeks.

Blood glucose is checked frequently, HbA1c is measured monthly, and diabetic eye screening is repeated because of the greater risk during pregnancy. Extra scans follow the baby's growth and, in many units, the heart. Women with type 1 diabetes should know how to check for ketones and what to do if unwell.

The mode and timing of birth depend on the baby's size, the mother's control and any complications. Birth in a consultant-led unit with neonatal facilities is usual. The NHS says glucose is measured hourly during labour, and an insulin and glucose infusion may be used to keep it steady.

Newborns of mothers with diabetes are at risk of low blood sugar, so the NHS advises feeding the baby within 30 minutes of delivery, followed by regular checks and a heel prick test within hours.

Insulin needs usually fall rapidly after delivery, and doses are cut back to avoid hypoglycaemia, especially when breastfeeding. The NHS notes a glucose check before discharge and again at the six-week postnatal check. Women with type 2 diabetes who stopped certain medicines should agree a plan for restarting them that is compatible with breastfeeding.

Diabetes-related eye and kidney reviews should be rebooked, and contraception and the longer-term care of diabetes should be addressed at the postnatal visit.

Contact your diabetes team or maternity unit the same day if glucose is persistently high, you have ketones with a type 1 diagnosis, you are vomiting and unable to keep fluids down, or you have frequent hypoglycaemia. Use 999 for confusion, loss of consciousness, a seizure or severe drowsiness, and call for urgent assessment if the baby's movements reduce.