General practice management of type 2 diabetes


Pregnancy with pre-existing type 2 diabetes
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☰ Table of contents


Recommendations

Reference

Grade*

Pre-pregnancy glycaemic control should be maintained as close to the non-diabetic range as possible, taking into account risk of maternal hypoglycaemia

65
SIGN, 2014

C

All women with diabetes should be prescribed† high-dose prepregnancy folate supplementation, continuing up to 12 weeks’ gestation

65
SIGN, 2014

B

All women with pre-gestational diabetes should be encouraged to achieve excellent glycaemic control‡

65
SIGN, 2014

D

Postprandial glucose monitoring should be carried out in pregnant women with gestational diabetes and may be considered in pregnant women with type 1 or 2 diabetes

65
SIGN, 2014

C

Pre-pregnancy care provided by a multidisciplinary team is strongly recommended for women with diabetes

65
SIGN, 2014

 C

*Refer to Summary, explanation and source of recommendations for an explanation of the level of evidence and grade of evidence
†5 mg of folate

‡HbA1c <48 mmol/mol (<6.5%) and consider stabilisation using metformin and/or insulin to achieve glycaemic targets. However, metformin has a category C rating in pregnancy. Continuation or initiation of metformin therapy should be considered only following full disclosure to the patient and under specialist supervision. Sulphonylureas may be associated with adverse neonatal outcomes and are thus best avoided65,230–233

All pregnant women with diabetes should be encouraged to achieve optimal glycaemic control.


Clinical context


GPs have a significant role in advising women of reproductive age with pre-gestational diabetes to consider the benefits of contraception to prevent inadvertent pregnancy before glycaemia can be optimised. Women should be advised of the need for advice, education and support to achieve optimal glycaemic control before pregnancy.234 Women with type 2 diabetes and PCOS or irregular periods must be advised that improved fertility may accompany use of metformin. Pre-pregnancy counselling should include assessment of diabetes complication status, review of all medications and commencement of folic acid (5 mg). Poor glycaemic control at conception and early in pregnancy is associated with increased risk of congenital malformations and first trimester miscarriages.

Women with pre-gestational diabetes (types 1 and 2) are more prone to the complications of pregnancy such as higher rates of pre-eclampsia prematurity and caesarean section.235 In addition, pregnancy may accelerate maternal complications of diabetes.236 Both maternal and fetal complications are increased by diabetes. Risk is progressive with increasing glycaemia.234

Good glycaemic control can mitigate the risk of maternal and fetal complications and the likelihood of birth trauma, and reduce the risk of early induction of labour and need for caesarean section.

Refer to  pregnancy and diabetes  for advice on pre-pregnancy blood glucose targets.
 

In practice


Pre-pregnancy

Where possible and practicable, formal pregnancy planning should occur prior to pregnancy and be patient focused, support self management and involve a multidisciplinary team on an individual basis. Deferring pregnancy should be a recommendation until glycaemic control is optimal. Women should be reassured that any reduction in HbA1c towards the individualised target is likely to reduce the risk of congenital malformations. Medications should be reviewed and ceased or replaced as appropriate.

It is important to do the following:

  • Advise that optimisation with a balanced diet, physical activity and healthy weight management may positively affect pregnancy outcomes.
  • Advise that nausea and vomiting in pregnancy may affect blood glucose control.
  • Advise that use of some form of contraception is recommended until glucose control is optimised.
  • Aim for glycaemic control to be as close to the normal (non-diabetic) range as possible, ensuring risks of maternal hypoglycaemia are minimised. The risk of fetal abnormalities increases with higher HbA1c levels at the time of conception and during the first trimester.
  • Review SMBG to determine if medication adjustment and/or commencement of insulin is required and assess risk of hypoglycaemia.
  • Recommend higher folate supplementation (5 mg) per day, starting one month before pregnancy237and continuing until 12 weeks of gestation to reduce the risk of neural tube defects.
  • Be aware that women treated for hypothyroidism may require higher doses of thyroid hormone replacement therapy.238 Based on re-assessment, a suggested dose change is a 30% increase in dose (eg if on one tablet per day, to increase by two tablets per week) may be needed.
  • Advise examination of the retina prior to conception and during each trimester for women with types 1 and 2 diabetes. More frequent assessment may be required if retinopathy is present. Patients with active moderate to severe non-proliferative retinopathy or with proliferative retinopathy who have not had an ophthalmological assessment within the preceding six months should undergo testing prior to pregnancy to see if the retinopathy is stable enough for pregnancy. Similarly, renal function should be tested if this has not been done within the preceding three months. Elevated creatinine or eGFR <45 mL/min/1.73 m2 or an ACR >30 mg/ mmol is an indication for pre-pregnancy nephrology review.239,240
  • Counsel the patient that the risks associated with diabetes in pregnancy can be reduced but not eliminated.

In pregnancy

Specialist endocrine and obstetric referral for multidisciplinary shared care is considered best practice.

Safety and risks of medications before and during pregnancy

Consideration of the safety of current therapies should be undertaken ideally before pregnancy is planned or urgently once pregnancy is confirmed. Consultation with local specialist services is advised. Agents such as sulphonylureas, glitazones, SGLT2i and incretin-based therapies will need to be reviewed or ceased, and insulin therapy instituted.

Metformin

Metformin is not associated with an increase in congenital malformation or early pregnancy loss, but remains a category C classified drug (refer to Table 14 for further information).241,242 Some diabetes services believe that metformin may be used as an adjunct or alternative to insulin in women with type 2 diabetes in the pre-conception period and during pregnancy. Consult with your local specialist endocrine and obstetric services.

Insulin

Rapid-acting insulin analogues aspart and lispro are safe to use during pregnancy.

There is insufficient evidence about the use of the long-acting insulin analogues (glargine – category B3). Detemir insulin (a long-acting insulin analogue) is now classified as category A drug in pregnancy. Patients already stabilised on insulin glargine may have this therapy continued in preference to switching to human insulin, but the B3 category rating needs to be discussed with the woman. Isophane insulin (Neutral Protamine Hagedorn [NPH] insulin) remains the most common long-acting insulin choice during pregnancy for women with type 2 diabetes (refer to Table 14 for further information).

Antihypertensive medications

ACEIs and angiotensin-II receptor antagonists should be discontinued during the pregnancy planning period or as soon as pregnancy is confirmed. Table 14 provides advice on antihypertensive agents to be avoided before and during pregnancy.

Table 14. Antihypertensive agents to be reviewed pre-conception and during pregnancy243

Antihypertensive agent

Category in pregnancy*

Advice

Angiotensin-converting enzyme inhibitors

D

Contraindicated

Angiotensin receptor blocker

D

Contraindicated

Calcium channel blocker

C

Avoid (except nifedipine)

β blockers

C

Avoid (except labetalol and oxprenolol)

Thiazide and loop diuretics

C

Seek advice

Methyldopa

A

Safe

Spironolactone

B3

Seek advice

Moxonidine

B3

Seek advice

*For definitions of the Australian categories for prescribing medicines in pregnancy, visit the Therapeutic Goods Administration, Australian categorisation system for prescribing medicines in pregnancy.

Statins

Statins should be discontinued during the pregnancy planning period or as soon as pregnancy is confirmed.

Antenatal care

Intensive glycaemic control guided by SMBG results is required in the management of diabetes in pregnancy. Insulin therapy will need regular review and titration to achieve glycaemic goals.

Close surveillance for new diabetes complications and monitoring of existing complications should occur routinely.

Ultrasound screening at 10–13 weeks’ gestation (with biochemistry) for trisomies, and at 18–20 weeks for congenital cardiac and other malformations, is advised. Pregnant women with diabetes should be offered ultrasound monitoring of fetal growth and amniotic fluid volume every four weeks from 28 to 36 weeks.240 Fetal growth and wellbeing monitoring should occur under specialist supervision. Consult with your local specialist endocrine and obstetric services.

Postpartum

The GP should maintain or re-establish contact with mother and child as early as practicable to address any issues arising from the pregnancy, labour, surgery or breastfeeding as well as review medications. Metformin may be continued while breastfeeding with minimal effect on the baby.244 Glycaemic monitoring and medications (especially insulin) need careful review during breastfeeding to minimise the risk of hypoglycaemia. Re-establishing glycaemic management goals, re-assessment of complications and timely contraceptive advice are also appropriate in the postnatal period.


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