Management of diabetes from preconception to the postnatal period: summary of NICE guidance

Why read this summary?

Diabetes in pregnancy is associated with risks to the woman (for example, higher rates of miscarriage, pre-eclampsia, and preterm labour) and to the developing fetus and baby (for example, higher rates of congenital malformations, macrosomia, birth injury, and perinatal mortality).^{1 2} This article summarises the most recent guidance from the National Institute for Health and Clinical Excellence (NICE) on how to manage diabetes and its complications from preconception to the postnatal period.³

Recommendations

NICE recommendations are based on systematic reviews of best available evidence. When minimal evidence is available, recommendations are based on the guideline development group’s opinion of what constitutes good practice. Evidence levels for the recommendations are given in italic in square brackets.

Preconception information for women with pre-existing diabetes

• From adolescence onwards, advise women about the importance of avoiding unplanned pregnancy. [Based on a high quality national clinical audit]

• Inform women and their families about how diabetes affects pregnancy and how pregnancy affects diabetes (box 1).

• Offer preconception care and advice to women who are planning to become pregnant before they discontinue contraception [based on high quality evidence from a meta-analysis of small to medium sized cohort studies and a health economic model]; inform them that establishing good glycaemic control before conception and continuing throughout pregnancy reduces—but does not eliminate—the risks of miscarriage, congenital malformation, stillbirth, and neonatal death [based on high quality evidence from a small non-randomised controlled trial and small to medium sized cohort studies].

• Offer a structured education programme (such as “dose adjustment for normal eating” (DAFNE) for type 1 diabetes, “diabetes education and self management for ongoing and newly diagnosed” type 2 diabetes (DESMOND), or X-PERT for type 2 diabetes) as soon as possible to women who are planning to become pregnant (unless they have already attended one).

Box 1 Effects of diabetes on pregnancy and effects of pregnancy on diabetes

Information and advice for women with diabetes and their families should cover the following points

• The role of diet, weight, and exercise (including weight loss advice for women who have a body mass index (kg/m²) above 27)

• The increased risk of having a baby who is large for gestational age, increasing the likelihood of birth trauma, induction of labour, and caesarean section

• The importance of maternal glycaemic control during labour and birth and early feeding of the baby to reduce the risk of neonatal hypoglycaemia

• The possibility of transient morbidity (such as hypoglycaemia or respiratory distress syndrome) in the baby during the neonatal period, which may require admission to a neonatal unit

• The risk of the baby developing obesity and/or diabetes in later life

For women with pre-existing diabetes information and advice should also cover the following points

• The need for folic acid supplementation (5 mg a day) until 12 weeks’ gestation to reduce the risk of having a baby with a neural tube defect

• The risks of hypoglycaemia and of hypoglycaemia unawareness during pregnancy and the effects of nausea and vomiting during pregnancy on glycaemic control

• The need for assessment of diabetic retinopathy and nephropathy before and/or during pregnancy (see box 2).

Glycaemic control before and during pregnancy

• Advise women with pre-existing diabetes who are planning to become pregnant to keep their HbA_1c concentration below 6.1% if this is safely achievable; reassure women that any reduction in HbA_1c towards the target of 6.1% is likely to reduce the risk of congenital malformations; women whose HbA_1c is above 10% should be strongly advised to avoid pregnancy [based on high quality evidence from a small non-randomised controlled trial and small to medium sized cohort studies].

• Offer monthly measurement of HbA_1c to women with pre-existing diabetes who are planning to become pregnant; do not use HbA_1c routinely for assessing glycaemic control in the second and third trimesters of pregnancy.

• Agree individualised targets for self monitoring of blood glucose concentration before and during pregnancy, taking into account the risk of hypoglycaemia; advise pregnant women with diabetes to keep their fasting blood glucose between 3.5 mmol/l and 5.9 mmol/l and their one hour postprandial blood glucose below 7.8 mmol/l if this is safely achievable [based on high quality evidence from small to medium sized randomised controlled trials and cohort studies].

The safety of medications for diabetes and its complications before and during pregnancy

• Metformin may be used for women with pre-existing diabetes as an adjunct or alternative to insulin in the preconception period and during pregnancy; discontinue all other oral hypoglycaemic agents before pregnancy and substitute with insulin.

• The rapid acting insulin analogues aspart and lispro are safe to use during pregnancy; isophane insulin is the first choice for long acting insulin during pregnancy.

• Discontinue angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists before pregnancy or as soon as pregnancy is confirmed; substitute with alternative antihypertensive agents suitable for use during pregnancy.

• Discontinue statins before pregnancy or as soon as pregnancy is confirmed.

Management of diabetic emergencies and complications during pregnancy

• Advise women with insulin treated diabetes of the risks of hypoglycaemia and of hypoglycaemia unawareness during pregnancy (particularly in the first trimester) [based on high quality evidence from a small cohort study]; provide a concentrated glucose solution (and glucagon for women with type 1 diabetes) and advise women and their partners or other family members on their use.

• Exclude diabetic ketoacidosis as a matter of urgency in women with type 1 diabetes who become unwell during pregnancy; admit women who are suspected of having diabetic ketoacidosis immediately for level 2 critical care, where they can receive medical and obstetric care [based on a small, well conducted cohort study and on the guideline development group’s clinical experience].

• Offer retinal and renal assessment to women with pre-existing diabetes before and during pregnancy because diabetic retinopathy may worsen during pregnancy and diabetic nephropathy is associated with adverse pregnancy outcomes (such as intrauterine growth restriction, pre-eclampsia, and preterm birth) (box 2).

Box 2 Retinal and renal assessment for women with pre-existing diabetes

• Offer retinal assessment to women seeking preconception care (unless she has had an annual retinal assessment in the previous six months) and annually thereafter if no retinopathy is found; offer retinal assessment after the first antenatal clinic appointment (or as soon as possible after the first contact during pregnancy if she has not had such an assessment in the preceding 12 months), and again at 28 weeks if the assessment is normal; conduct an additional assessment at 16-20 weeks for women in whom diabetic retinopathy is present at the first antenatal care appointment; use digital imaging with mydriasis using tropicamide for retinal assessment.

• Offer renal assessment (including measurement of microalbuminuria) to women before they discontinue contraception; arrange renal assessment at the first contact during pregnancy if it has not been done in the preceding 12 months; consider referral to a nephrologist before discontinuing contraception if the serum creatinine concentration is 120 μmol/l or higher (or if the estimated glomerular filtration rate is less than 45 ml/min/1.73 m²) and during pregnancy if the serum creatinine concentration is 120 μmol/l or higher or if total protein excretion exceeds 2 g a day (do not use the estimated glomerular filtration rate during pregnancy); consider thromboprophylaxis for pregnant women with proteinuria above 5 g a day.

Gestational diabetes

• Use risk factors (raised body mass index, previous macrosomic baby, previous gestational diabetes, family history of diabetes, and family origin with a high prevalence of diabetes) to decide which pregnant women to test for gestational diabetes (box 3). In these women test for gestational diabetes using a two hour 75 g oral glucose tolerance test (OGTT) and the World Health Organization’s diagnostic criteria for gestational diabetes. In women who have had gestational diabetes in a previous pregnancy, offer early self monitoring or an OGTT at 16-18 weeks and a further OGTT at 28 weeks if the results are normal; in women with any of the other risk factors for gestational diabetes offer an OGTT at 24-28 weeks. Do not screen using fasting plasma glucose, random blood glucose, glucose challenge test, or urine analysis for glucose [all these recommendations are based on high quality evidence from small to medium sized diagnostic accuracy studies, a medium sized randomised controlled trial, and a health economic model].⁴

Box 3 Risk factors for determining testing for gestational diabetes in routine antenatal care

• Body mass index above 30

• Previous macrosomic baby weighing 4.5 kg or more

• Previous gestational diabetes

• Family history of diabetes (first degree relative with diabetes)

• Family origin with a high prevalence of diabetes (South Asian, black Caribbean, or Middle Eastern)

• Inform women with gestational diabetes about the effects of gestational diabetes on pregnancy (box 1); tell them that good glycaemic control throughout pregnancy will reduce the risk of fetal macrosomia, trauma during birth (to themselves and the baby), induction of labour or caesarean section, neonatal hypoglycaemia, and perinatal death; and instruct them in self monitoring of blood glucose. Targets for blood glucose control are the same as for women with pre-existing diabetes.

• Consider hypoglycaemic therapy if diet and exercise fail to maintain blood glucose targets during a period of one to two weeks; also consider hypoglycaemic therapy if ultrasound investigation suggests incipient fetal macrosomia (abdominal circumference above the 70th centile).

• Tailor hypoglycaemic therapy for women with gestational diabetes to the glycaemic profile of and acceptability to the individual woman (hypoglycaemic therapy comprises one or more of: regular insulin, the rapid acting insulin analogues lispro and aspart, the hypoglycaemic agents metformin and glibenclamide).

Antenatal care appointments

• Offer pregnant women with diabetes immediate contact with a joint diabetes and antenatal clinic; contact with the diabetes care team for assessment of glycaemic control should occur every one to two weeks; antenatal appointments should cover care specifically for women with diabetes (box 4) in addition to the care provided routinely for healthy pregnant women.

• Prioritise women with diabetes for examination of the four chamber view of the fetal heart and outflow tracts at 18-20 weeks [based on high quality evidence from small to medium sized cohort studies, a high quality national clinical audit, and a health economic model].

Box 4 Specific care for women with diabetes during pregnancy

Offer ongoing opportunities for information and education and provide the following care in addition to (or, where indicated, instead of) routine antenatal care.*

• First appointment (joint diabetes and antenatal clinic)—Offer information, advice, and support for optimising glycaemic control; take a clinical history to establish the extent of diabetes related complications; review medications for diabetes and its complications; and offer retinal and/or renal assessment if no assessment has been done in the previous 12 months

• At 7-9 weeks—Confirm viability of pregnancy and gestational age

• Booking appointment (ideally by 10 weeks)— Discuss information, education, and advice about how diabetes will affect the pregnancy, birth, and early parenting (such as breastfeeding and initial care of the baby)

• At 16 weeks—Offer retinal assessment to women with pre-existing diabetes who showed signs of diabetic retinopathy at the first antenatal appointment

• At 20 weeks—Offer four chamber view of the fetal heart and outflow tracts plus scans that would be offered at 18-20 weeks as part of routine antenatal care

• At 28 weeks—offer ultrasound monitoring of fetal growth and amniotic fluid volume, and offer retinal assessment to women with pre-existing diabetes who showed no diabetic retinopathy at their first antenatal clinic visit

• At 32 weeks—Offer ultrasound monitoring of fetal growth and amniotic fluid volume, and for nulliparous women offer all investigations that would be offered at 31 weeks as part of routine antenatal care

• At 36 weeks—Offer ultrasound monitoring of fetal growth and amniotic fluid volume. Also offer information and advice about timing, mode, and management of birth; analgesia and anaesthesia; changes to hypoglycaemic therapy during and after birth; management of the baby after birth; initiation of breast feeding and the effect of breast feeding on glycaemic control; contraception; and follow-up

• At 38 weeks—Offer induction of labour (or caesarean section if indicated) and start regular tests of fetal wellbeing for women who are awaiting spontaneous labour

• At 39, 40, and 41 weeks—Offer tests of fetal wellbeing for women who are awaiting spontaneous labour

* Women with diabetes should also receive routine care according to the schedule of appointments in the NICE guideline on antenatal care for healthy pregnant women,⁵ including appointments at 25 weeks (for nulliparous women) and 34 weeks, but with the exception of the appointment for nulliparous women at 31 weeks

Preterm labour in women with diabetes

• Antenatal steroids for fetal lung maturation are not contraindicated but should be administered with additional insulin in women with insulin treated diabetes.

• Tocolysis is not contraindicated, but do not use betamimetics for tocolysis in women with diabetes.

Timing and mode of birth

• Offer an anaesthetic assessment in the third trimester to women with comorbidities such as obesity or autonomic neuropathy; if general anaesthesia is used for the birth, monitor blood glucose every 30 minutes from induction of general anaesthesia until after the baby is born and the woman is fully conscious.

• Offer elective birth after 38 completed weeks (induction of labour or, if indicated, elective caesarean section); inform women who have a macrosomic fetus that has been diagnosed with ultrasound about the risks and benefits of vaginal birth, induction of labour, and caesarean section.

Glycaemic control during labour and birth

• Monitor capillary blood glucose hourly during labour and birth to maintain a concentration between 4 mmol/l and 7 mmol/l; if the concentration is not maintained in this range, use intravenous dextrose and insulin infusion during labour and birth.

• In women with type 1 diabetes, consider intravenous dextrose and insulin infusion from the onset of labour.

Initial assessment and care of the newborn baby

• Advise women to give birth in hospitals where advanced neonatal resuscitation skills are available 24 hours a day; keep babies with their mothers unless a clinical complication or abnormal clinical signs arise that warrant admission for intensive or special care [based on the national service framework for diabetes and a high quality national clinical audit].

• Feed babies as soon as possible after birth (within 30 minutes) and then every two to three hours until feeding maintains prefeed blood glucose concentrations of at least 2.0 mmol/l. Test blood glucose concentrations at two to four hours after birth. Only if concentrations are below 2.0 mmol/l on two consecutive readings despite maximal support for feeding, or if there are abnormal clinical signs, or if the baby will not feed orally effectively, should additional measures such as tube feeding or intravenous dextrose should be given. Test blood glucose in babies who present with clinical signs of hypoglycaemia (such as abnormal muscle tone or level of consciousness, fits, apnoea) and start treatment with intravenous dextrose as soon as possible.

• Perform echocardiography for babies who show clinical signs associated with congenital heart disease (including heart murmur) or cardiomyopathy.

• Do not test for polycythaemia, hyperbilirubinaemia, hypocalcaemia, or hypomagnesaemia unless the baby has clinical signs.

• Recognise criteria for admission to a neonatal unit, such as hypoglycaemia associated with abnormal clinical signs, respiratory distress, signs of cardiac decompensation, or neonatal encephalopathy (box 5).

Box 5 Criteria for admission to neonatal unit

• Hypoglycaemia associated with abnormal clinical signs

• Respiratory distress

• Signs of cardiac decompensation resulting from congenital heart disease or cardiomyopathy

• Signs of neonatal encephalopathy

• Signs of polycythaemia and likely to need partial exchange transfusion

• Need for intravenous fluids

• Need for tube feeding (unless adequate support is available on the postnatal ward)

• Jaundice requiring intense phototherapy and frequent monitoring of bilirubinaemia

• Delivery before 34 weeks (or at 34-36 weeks if dictated clinically by initial assessment of the baby and feeding on the labour ward)

Postnatal management of diabetes

Pre-existing diabetes

• Reduce insulin immediately after the birth in women with insulin treated pre-existing diabetes. Monitor blood glucose levels carefully to establish the appropriate dose, and inform women of the increased risk of hypoglycaemia in the postnatal period, especially if breast feeding (when a meal or snack before or during feeds is advisable).

• Resume (or continue) use of metformin and glibenclamide immediately after birth in women with pre-existing type 2 diabetes who are breast feeding.

• Continue to avoid any drugs for treating diabetes complications that were discontinued for safety reasons in the pre-conception period.

• Refer women with pre-existing diabetes back to their routine diabetes care arrangements; remind them of the importance of contraception and the need for preconception care when planning future pregnancies.

Gestational diabetes

• Discontinue hypoglycaemic therapy immediately after the birth in women who were diagnosed with gestational diabetes; test their blood glucose to exclude persisting hyperglycaemia before transfer to community care, and remind them of the symptoms of hyperglycaemia.

• Offer lifestyle advice (on weight control, diet, and exercise) and a fasting plasma glucose measurement (but not an OGTT) at the six week postnatal check and annually thereafter [based on well conducted systematic reviews of randomised clinical trials and on a small diagnostic accuracy study].

• Provide information about the risk of gestational diabetes in future pregnancies, offer screening for diabetes when planning future pregnancies, and offer early self monitoring of blood glucose or an OGTT in future pregnancies.

Overcoming barriers

This guidance for care of women with diabetes and their families aims to empower them so that pregnancy and child birth are positive experiences. For example, uptake of preconception care is encouraged by using every contact with healthcare professionals (including the diabetes care team) to inform women of childbearing age about the benefits of preconception glycaemic control and every contact with the diabetes care team to document intentions about pregnancy and contraceptive use, and by also giving preconception care in a supportive environment, with the woman’s partner or other family members encouraged to attend. Other recommendations aim to prepare women for the additional time and effort required to manage diabetes during pregnancy and to provide maximal support for women who wish to breast feed.

To support implementation, NICE and the guideline development group have developed a version of the guidance (available at www.nice.org.uk/CG063PublicInfoEnglish) that can be given to women with pre-existing diabetes, women who are planning to become pregnant, and women’s partners or families.

Further information on the guidance

Background

About 650 000 women give birth in England and Wales each year,⁶ and 2-5% of pregnancies involve women with diabetes.^{7 8}Among pregnancies in which the woman has diabetes, about 87.5% involve gestational diabetes (which may or may not resolve after pregnancy), 7.5% involve type 1 diabetes, and 5% involve type 2 diabetes.³ The adverse outcomes associated with pregnancy complicated by diabetes together with the increasing prevalence of type 1 and type 2 diabetes (especially the increasing prevalence of type 2 diabetes in people of African, black Caribbean, South Asian, Middle Eastern, and Chinese family origin)⁷ highlight the need for effective clinical care to improve outcomes for women with diabetes and their babies.

What’s new?

This guidance builds on existing guidance for the routine care of type 1 and type 2 diabetes^{9 10} and for routine antenatal, intrapartum, and postnatal care.^{5 11 12} It emphasises aspects of maternity care that are additional or different for women with diabetes in pregnancy.

Methods

The guidance was developed by the National Collaborating Centre for Women’s and Children’s Health in accordance with NICE guideline development methods (see www.nice.org.uk/page.aspx?o=114219). The collaborating centre established a guideline development group consisting of healthcare professionals and patient and carer representatives, with experts in guideline methodology from the collaborating centre. The guideline development group identified and appraised clinical evidence and evaluated cost effectiveness of interventions where possible. Stakeholder organisations were invited to comment on a draft of the guideline that was subsequently revised to take account of comments received.

NICE has produced four different versions of the guideline: a full version containing all the evidence and the recommendations; a quick reference guide; a version known as the “NICE guideline” that lists the recommendations; and a version for patients and the public. All these versions are available from the NICE website (www.nice.org.uk/CG063). Future updates of the guidance will be produced as part of the NICE guideline development programme.¹³

Key areas for future research

• Clinical and cost effectiveness of screening techniques for gestational diabetes (risk factor screening, two stage screening using glucose challenge test and OGTT, or universal OGTT)

• Clinical and cost effectiveness of ambulatory continuous blood glucose monitoring in pregnancies complicated by diabetes

• Comparison of new generation continuous subcutaneous insulin infusion (insulin pump therapy) with intermittent insulin injections for women with type 1 diabetes in pregnancy

• Identifying the fetus at risk of intrauterine death in women with diabetes

• Optimal methods for controlling glycaemia during labour and birth