Pregnancy: women with diabetes mellitus

Planning for a pregnancy is important for all women and encompasses several elements such as advice on smoking cessation, alcohol consumption, healthy eating, folic acid supplements and contraception. For women with diabetes this need to plan has even greater importance. 

For these women there is the additional importance of optimising their glycaemic control and assessing for the presence of the complications of diabetes prior to pregnancy. In an effort to prevent early pregnancy loss and congenital malformations in infants, optimal medical care, patient education and training must begin before conception. This is best accomplished through a multidisciplinary team approach. Ultimately, however, the woman with diabetes must become the most active member of the team.¹

As well as coping with the normal emotional and physiological diversity of pregnancy, the intensity of the management of diabetes is increased during this time.² Coping with intensive treatment to achieve good glycaemic control for pregnancy is difficult, and motivation is an important factor in the long-term success of the regimen.³ However the reality of unplanned pregnancy remains a challenge to all.

Diabetes and pregnancy

Despite significant advances in diabetes management, and particularly its management during pregnancy, major congenital malformations remain the leading cause of mortality and serious morbidity in the infants of women with established diabetes mellitus.^3-6

There is significant evidence correlating sub-optimal glycaemic control during early pregnancy with the increased likelihood of birth defects in these infants.^7-9

Specifically hyperglycaemia during the period of organogenesis, which is during the first eight weeks post-conception, can have a teratogenic effect. More often these malformations occur before the woman even realises that she is pregnant.¹⁰ Therefore it is essential for women with diabetes that specialist care commences before pregnancy in order to reduce the rate of these anomalies.^11-14

Pre-pregnancy clinic

A dedicated pre-pregnancy clinic was established within the general diabetes service at the Mater Misericordiae University Hospital in 2004. The purpose of this is to assist women with established diabetes to achieve optimal glycaemic control, to treat any diabetes or other medical conditions and to ensure that the women attending are in the best possible general health prior to pregnancy. 

The over-arching aim is to encourage planned pregnancies. Those attending are discouraged from smoking and excessive alcohol consumption during the pre-pregnancy period and folic acid supplementation (5mg daily) is advocated. Weight management is also addressed, as maternal pre-pregnancy obesity has been independently associated with adverse pregnancy outcomes.¹⁵

Glycaemic control

Women attending for pre-pregnancy care are reviewed regularly. Their diabetes management and control are assessed and alterations to treatment made as necessary to achieve the pre-pregnancy targets. Attendees are requested to test their capillary blood glucose levels at least seven times per day, before and one hour after all meals as well as pre-bedtime. They aim to achieve pre-meal glucose of 5.0mmol/l or less and one hour post-meal values of less than 7.0mmol/l.¹⁶

HbA1c levels are monitored regularly and women advised to avoid trying to conceive until they have reached target ideally for three months. To achieve these targets often complex insulin regimens used. When necessary continuous subcutaneous insulin infusions (CSII) are commenced to help achieve the targets.

Diabetes complications 

Much of the focus of pre-pregnancy care relates to foetal anomalies, however consideration should also be given to the woman with diabetes in relation to screening for complications. Of particular importance are the microvascular changes associated with diabetes. All women should have retinal screening during this time. The aim is to identify if retinopathy is present and if it is necessary to treat it in order to avoid rapid progression of retinal disease during pregnancy that could lead to permanent deterioration. 

Screening for the presence of nephropathy is also advocated, as it has been associated with increased maternal and perinatal morbidity.¹⁷ The prevalence of pre-term deliveries is considerably increased in women with microalbuminuria, predominantly due to pre-eclampsia. The albumin excretion level in conjunction with metabolic control at the time of conception is a predictor of this.¹⁷ In the presence of overt diabetic nephropathy, and particularly if serum creatinine levels are abnormally high, there is an increased risk of permanent deterioration in maternal renal function, poorer obstetric outcomes and congenital malformations in the infants of these women.^18,19

Macrovascular complications of diabetes are also associated with increased maternal mortality and specific care is required for these women, particularly those with ischaemic heart disease.

The pre-pregnancy clinic facilitates an assessment and stabilisation of diabetes complications in order to minimise the risk to the mother during pregnancy. It is rare that a woman may be advised against proceeding to plan a pregnancy, a decision that is never taken lightly and always guided by the intention of avoiding permanent deterioration to the woman’s health.

Type 2 diabetes 

The increasing prevalence of type 2 diabetes is well recognised. Pregnancy planning for women with type 2 diabetes poses its own challenges. Women in this group tend to be older and more likely to be overweight. Pregnancy complicated by type 2 diabetes mellitus should be considered high-risk as the rate of spontaneous abortions and congenital malformations are significantly higher than those seen with type 1 diabetes.²⁰ It is imperative that they are referred for specialist diabetes care with access to a pre-pregnancy service. 

Assisted reproduction

The incidence of people requiring treatment for infertility has increased worldwide.²¹ If a woman with diabetes is planning to undergo investigations or treatment for infertility it is important that her glycaemic control has been optimised prior to commencing any treatment. Such women should be referred to a dedicated pre-pregnancy clinic.

Referral to the pre-pregnancy clinic

Once a woman has a diagnosis of diabetes they can be referred to this clinic. If they are attending a general diabetes clinic their care can be temporarily transferred to our service until they become pregnant at which time their care is then transferred to the combined obstetric diabetes clinic in the maternity services. Following pregnancy these women return to their original diabetes services.

Conclusion

Sub-optimal glycaemic control at conception and during early pregnancy has been strongly correlated with increased fetal loss and congenital abnormalities in infants of women with established diabetes.  It has been demonstrated that if these women improved their glycaemic control prior to and during early pregnancy the rate of these abnormalities can be reduced. The provision of pre-pregnancy care needs to be considered as part of the management for all women of reproductive age with diabetes mellitus. This may necessitate referral to a specialist centre for care such as the pre-pregnancy clinic at the Mater Hospital. 

The challenge now is how best to inform all women of reproductive age with diabetes about the importance of obtaining specialist care prior to becoming pregnant.  

References

1. American Diabetes Association (2003) Preconception care of women with diabetes. Diabetes Care 2003; 26(1): S91-S93
2. Firth RG. Insulin therapy in diabetic pregnancy. In Diabetes and Pregnancy: An International Approach to Diagnosis and Management. Wiley and Sons Ltd: London, 1996
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6. American Diabetes Association Preconception care of women with diabetes. Diabetes Care 2002; 25(1); S82-S84
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16. Health Service Executive. Guidelines for the management of pre-gestational and gestational diabetes mellitus form pre-conception to the post natal period. Health Service Executive: Ireland, 2010 
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18. Mackie A, Doddridge, Gamsu H et al. Outcomes of pregnancy in patients with insulin dependents diabetes mellitus and nephropathy with moderate renal impairment. Diabetic Medicine 1996; 13: 90-96
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21. Inhorn MC. Global infertility and the globalisation of new reproductive technologies: illustrations from Egypt. Social Science and Medicine 2003; 56(9): 1837-185