Pregnancy poses additional risks for women with diabetes. The most recent CEMACH (Confidential Enquiry into Maternal and Child Health) report continues to show that babies of women with diabetes are five times as likely to be stillborn, three times as likely to die in their first months of life and twice as likely to have major congenital malformation (this last number maybe higher as it is not adjusted for the higher rate of terminations where congenital malformations are found). Although the majority of mothers with pre-existing diabetes have type 1 diabetes, the proportion of births to women with diabetes is rising due to the rising numbers of young women with Type 2 diabetes. Worryingly, some of the latter group are only diagnosed in pregnancy.
Given the elevated risk, all women of child bearing age should be counselled about their pregnancy intentions especially as the use of drugs with potentially teratogenic effects are increasingly being used in this age group (e.g. ACE inhibitors) and should be stopped. Planning a pregnancy will also enable the tightening of glycaemic control, ideally with tighter targets – 42mmol/mol (6.1%) if achievable. For women with type 2 diabetes, metformin is considered safe whilst other oral hypoglycaemic agents should be stopped due to either teratogenicity (thiazolidenediones) or a paucity of safety evidence (gliptins, SGLT2 inhibitors & GLP1 analogues).
Many patients require adjustment to their insulin treatment to achieve tight control whilst avoiding hypoglycaemia, often transferring to a basal bolus regimen or even an insulin pump. The use of most analogue insulin are considered safe although most evidence relates to Humalog and Novorapid with regard to fast acting analogues. Screening for complications, especially retinopathy should be updated and all women planning pregnancy should be commenced on a higher dose of folic acid than used in non-diabetic women (5mg daily) which should be continued until the end of the first trimester.
When pregnancy is confirmed, the above guidance is still applicable although many women present well into their first trimester. Most women are seen in a secondary care setting with joint clinics held with the diabetes specialist team and obstetricians. Unsurprisingly, NICE guidance exists but has recently been updated to recommend the use of aspirin in all women during the second and third trimesters. Since 2014, the use of vitamin D supplements is also recommended.
Dr Mark Freeman