Download Guidelines for the Management of Type 1 Diabetes in Pregnancy

Guidelines for the Management of Diabetes in Pregnancy
Royal United Hospital
January 2006
TYPE 1 DIABETES
Background
Approximately 2-4/1000 women who become pregnant have previously diagnosed type 1
diabetes. In women with diabetes there are greater risks both to the mother and the fetus.
Fetus
 Despite advances in diabetes care, babies born to women with type 1diabetes are
almost 5 times as likely to be stillborn and nearly 3 times as likely to die in the
first month of life as those in women without diabetes. The babies are also twice
as likely to have a major congenital malformation (Confidential enquiry into
maternal and child health, Oct 2005). Cardiac and neural tube defects occur
approximately 3 times more often than the background population. Many have
multiple congenital abnormalities.
 The most common problem seen in the infant is macrosomia which can result in
birth trauma.
 Fetal hyperinsulinaemia that results from maternal hyperglycaemia causes
neonatal hypoglycaemia and also accelerates skeletal maturation and delays
pulmonary maturation. Infants also have an increased risk of jaundice and are at
higher risk of polycythaemia.
Maternal
 Early in pregnancy, women with diabetes have an increased risk of miscarriage.
 Pregnant women with diabetes are likely to notice a change in their insulin
requirements. Particularly in the early stages there may be increased risk of
hypoglycaemia, with the risk of hypoglycaemia unawareness. Later in the
pregnancy as insulin requirements increase, there may be an increased risk of
diabetic ketoacidosis.
 Diabetic retinopathy can worsen during pregnancy especially if there is a rapid
change in glycaemic control, and may require laser treatment.
 Women with diabetes have a higher risk of infections than women without
diabetes and 2-3 times the risk of pre-eclampsia. Polyhydramnios is also more
likely with an increased risk of premature labour and postpartum haemorrhage.
 Women with diabetes and vascular disease are also at risk of intrauterine growth
retardation.
 During the birth they are at increased risk of obstructed labour, especially
shoulder dystocia and a greater intervention rate.
1
Pre-Pregnancy Management

Diabetic women of child bearing age will be seen in the general diabetes
outpatient clinic. Information and counselling should be provided to all these
women so that they are aware of the problems of diabetes in pregnancy, potential
dangers of an unplanned pregnancy and the benefits of pre-pregnancy
counselling.

Diabetic women should be advised not to contemplate pregnancy until their
glycaemic control has been optimised (HbA1c <7%) and guidance should be
provided from the diabetic team in order to achieve this. They should also be
advised to stop smoking if they smoke.

Diabetic women planning pregnancy should be prescribed 5mg folic acid.

During pre-pregnancy planning, the need for any potential teratogenic drugs (e.g.
anti-hypertensives,) should be reviewed and swapped to drugs that are safe during
pregnancy (if necessary).

Statins should be stopped

Assessment of diabetes complications
o Retinopathy – retinopathy that requires laser treatment should be treated
before pregnancy as pre-existing retinopathy may progress more rapidly
during pregnancy.
o Nephropathy – screen using albumin/creatinine ratio. If > 3.4mg/mmol on
screening an overnight sample should be collected.
o Macrovascular disease – pre-existing heart disease requires cardiological
review before conception.
o Autonomic neuropathy may severely complicate the management of
diabetes in pregnancy, and women should be aware of the risks involved.

Thyroid function should be checked as abnormalities in women with type 1
diabetes are common and may adversely affect pregnancy outcomes.
2
Ante-Natal Management

Women should be booked into the joint diabetes/ante-natal clinic as soon as
they find out they are pregnant. Ensure patients are taking folic acid at 5mg dose
and any teratogenic medications have been stopped if pregnancy was not
planned.

During the first visit, the woman should be given the relevant telephone
numbers of the diabetes specialist nurses working in her area and the hospital
diabetes specialist nurses, so they have someone to call for advice.

Glycaemic control will be checked at the booking visit (HbA1c and
fructosamine). Other routine investigations such as urea and electrolyes, random
lipids and urine microalbumin will be carried out , if no recent record. If
possible dilated fundoscopy should be undertaken (if patient driving this should
be arranged for the next visit), unless a digital photograph has been done within
the last 2 months.

Women should be advised to keep a record of their pre-pregnancy insulin doses.

It should be explained that insulin requirements are likely to change during the
pregnancy:
o Initially in the first trimester insulin requirements are relatively stable,
depending on the amount of nausea experienced. If morning sickness is a
problem, it is often appropriate for them to take their insulin after they
have eaten if taking a rapid acting analogue with meals. After 12 weeks
and before 20 weeks insulin requirements may drop and recurrent
hypoglycaemia can become a problem. Women should be advised to cut
back on their insulin. If hypoglycaemia is recurrent or severe, women will
be advised that they need to take greater care when driving or operating
machinery. In some cases, particularly when awareness is lost women are
advised not to drive for a period of time.
o As the pregnancy progresses into the second trimester, insulin
requirements rise and continue to increase until about 34 weeks. Women
must increase their insulin as they see their blood glucose values starting
to rise. Requirements are often twice the original starting dose and
increases may be needed every two to three days.

Ultrasound scanning will be performed at approximately 7 weeks gestation to
confirm a viable pregnancy.
3

During the pregnancy women will be seen at 1-4 weekly intervals in the first
and second trimester and 1-2 weekly in the third trimester, depending on
glycaemic control and circumstances.

Women will be advised to carry out at least 4 blood glucose measurements per
day. Target blood glucose readings should be between 4 - 6 mmol/l before
meals and < 8 mmol/l two hours post prandially.

Fructosamine blood tests are carried out every 4 weeks with the aim to keep
within normal range. The nomal range falls as each trimester occurs. 1st
Trimester <285, 2nd 260, 3rd 240.

HbA1c will be taken at first visit and in each trimester.

Metabolic control will be monitored by reviewing patient’s home blood glucose
monitoring diaries and fructosamine results and changes to the insulin regime
will be suggested.

Women who are on twice daily insulin will be advised to swap to a basal bolus
regime after approximately 12+ weeks.

Dilated fundoscopy will be undertaken in the first trimester, unless under the
care of an ophthalmologist. If normal there is no need to repeat this unless the
patient reports visual disturbance. If any changes are seen then dilated
fundoscopy should be repeated every trimester. If patient is under an
ophthalmologist they should be informed that the patient is pregnant and asked
whether earlier review is required.

Proteinuria should be assessed by dipstick at regular intervals and quantified
where appropriate. An MSU should be sent to first exclude infection. If more
than 1+ confirmed on two samples a 24 hour collection should be taken and
repeated at four weekly intervals.

From 24 weeks gestation ultrasound scans will be performed to assess fetal
growth, every 2-4 weeks.

Recurrent or severe hypoglycaemia during the latter part of the third trimester
raises the possibility of placental insufficiency, therefore a reduction in insulin
requirement by 15-20% over a 1-2 day period should not be ignored and patient
should be reviewed by the obstetric team, with a view for admission for
observation.

It is expected that the gestational period will not go beyond 38 weeks gestation
due to the increased risk of late intra-uterine death.
4
Management During Labour
When admitted the obstetric registrar and the diabetes team must be informed. It is
enough to inform the diabetes nurse by leaving a message on her answer phone (4198) or
if more urgent help is required she can be contacted via her bleep (7721). If help is
required out of hours, the medical registrar on call should be contacted via switchboard.
If necessary one of the diabetes consultants can be contacted through switchboard.
Spontaneous Onset of Labour

As soon as labour is confirmed a suitable insulin regime (below) should be
prescribed.

An insulin infusion will be commenced through a syringe pump containing 50
units of actrapid in 50ml of N-saline.

A 500ml infusion of 5% dextrose with 10mmol potassium if K+ less than
4mmol/l should run simultaneously over 5 hours.
Blood Glucose (meter)
Infusion Rate (Units/hour)
<4.0
4.0 – 6.5
6.6 – 8.9
9.0 – 11.0
11.1 – 17.0
17.1 – 28.0
>28
0 (recheck blood glucose in 30 minutes)
1
2
4
5
6 (call doctor)
8 (call doctor)

Potassium should be checked before the infusion is commenced and then 6-8
hourly, if further infusion is required.

If potassium levels are outside the range of 3.5-5mmol/l it may be necessary to
alter the amount of KCl in the dextrose bag (below)
Potassium (mmol/l)
<3.5
>5.0


Action
20mmol per bag
No potassium in bag
Blood glucose should be checked hourly until delivery.
If failing to achieve target of 4.5-6, check syringe pump and if everything is
working, double insulin infusion rates for each gradient.
5

If blood glucose remains persistently low, change to 10% dextrose.

If blood glucose >17mmol/l, check laboratory blood glucose and check urine for
ketones, if >1+ and/or if blood glucose confirmed change infusion to N-saline,
and contact the medical team.
Induction of Labour

The induction should be booked in the labour ward diary and arranged in liaison
with the diabetes and paediatric departments.

Women should be admitted on the day of induction having had their meal and
usual insulin.

As labour is established the intravenous regime of insulin and dextrose should be
started.
First Stage of Labour
 The obstetric registrar should be informed if progress is slow. If secondary arrest
of labour occurs in a multiparous diabetic woman syntocinon should not be used
unless specifically authorized by the consultant on call because of the risk of fetal
macrosomia.
Second Stage of Labour

Should be allowed to proceed as for a normal labour.

Paediatrician should be informed and attend the delivery.

Obstetric registrar should be informed if second stage of labour exceeds one hour
in a multigravida or 2 hours in a primigravida unless delivery is imminent.
Elective Caesarean Section
(i) Morning lists

The section should be booked in the labour ward diary and arranged in liaison
with the diabetes, anaesthetic and paediatric departments.

The woman should be admitted the night before the planned section and should
receive her normal evening dose of insulin.

From midnight she should be “nil by mouth” and her morning dose of insulin
omitted.
6

The intravenous regime of insulin and dextrose should be started at least one hour
before the planned section and no later than 08.30.

Blood glucose should be checked ½ to one hourly until stable.

A paediatrician should be informed and attend the delivery.
(ii) Afternoon lists

The woman may be admitted at 8am on the morning of the planned surgery

She may have a light breakfast and appropriate insulin before leaving home

After this she should be ‘nil by mouth’

The intravenous regime of insulin and dextrose should be started at least one hour
before the planned section and sooner if the woman becomes hypoglycaemic.

Blood glucose should be checked ½ to one hourly until stable.
A paediatrician should be informed and attend the delivery
Post-Natal Management

Continue the insulin infusion until patient is eating, if blood glucose levels low
halve the infusion rate.

Continue to monitor blood glucose hourly for at least 4 hours, then 2-4 hourly
until mother is eating normally.

When stopping the infusion administer subcutaneous insulin 30 minutes
beforehand, with food.

The subcutaneous insulin dose should be approximately 75% of the prepregnancy insulin dose (this is the insulin doses she was using prior to conception,
not prior to delivery). In the first two weeks after delivery insulin levels may need
to be cut further, but tend to rise back to pre-pregnancy levels after this period of
time

If breast feeding women should be advised to eat an extra 30-50g of carbohydrate
per day. When feeding during the night it is advised to have a small carbohydrate
snack with each feed.
7

Tight glycaemic control should not be employed in the immediate post-natal
period and target blood glucose readings should be 4-8mmol/l pre-prandially.

Ideally the mother and her insulin regime should be reviewed by a member of the
diabetes team prior to mother and baby being discharged.

The mother’s glycaemic control and insulin regime is reviewed at the post natal
clinic visit which should be arranged 6 weeks post delivery.

Fructosamine should be checked 5 weeks after delivery so that result is available
in clinic

Further diabetes follow up for the mother should be arranged at the general
diabetes outpatient clinic.
8
TYPE 2 DIABETES
Background



In the CEMACH study (2005), type 2 diabetes was found to account for over 25%
of all pre-gestational diabetic pregnancies.
It was strongly associated with social deprivation and being a member of an
ethnic minority group.
It was found that pregnancy in women with type 2 diabetes carried as great a risk
of an adverse outcome as in those with type 1 diabetes.
Pre-conceptual and Antenatal Management
All patients with type 2 diabetes planning a pregnancy should be referred to the
diabetes service before contemplating conception.
They should all be blood glucose monitoring
Target blood glucose are as in type 1 patients and HbA1c should be <7% but
preferably lower (<6.5%)
Insulin Treated

Generally the management of women with type 2 diabetes managed with insulin
will follow that of women with type 1 diabetes.
Tablet Treated

In patients usually managed with tablets, plans will be advised to switch to a basal
bolus insulin regime pre-conceptually.

If pregnancy is unplanned, the woman should be seen as soon as pregnancy is
confirmed and transferred to insulin at that point.

Throughout the pregnancy, patients will then be treated in the same way as those
with type 1 diabetes.
Diet Treated

It is likely that women in this group will need insulin at some stage of their
pregnancy.
9

They should be seen in the joint clinic as soon as pregnancy is confirmed so that
they can be closely monitored and insulin started as soon as necessary.

Women will be treated in a similar fashion to those with type 1 diabetes.
Management During Labour
The management of women with type 2 diabetes during labour should be exactly the
same as those with type 1 diabetes.
Post-Natal Management
Insulin Treated
Women with type 2 diabetes treated with insulin prior to pregnancy should be treated in
the same way as those with type 1 diabetes.
Tablet Treated
Breast Feeding

Patients who wish to breast feed who were treated with tablets pre-conceptually
will need to remain on an insulin regime, and should be treated in the same way
as those with type 1 diabetes.

They should be advised to return to 75% of their pre-pregnancy doses (or initial
pregnancy doses if not commenced on insulin until pregnant)

Tight glycaemic control should not be employed in the immediate post-natal
period and target blood glucose readings should be 4-8mmol/l pre prandially.

Ideally the mother and her insulin regime should be reviewed by a member of the
diabetes team prior to mother and baby being discharged.

The mother’s glycaemic control and insulin regime is reviewed at the post natal
clinic visit which should be arranged 6 weeks post delivery.

Fructosamine should be checked 5 weeks after delivery so that result is available
in clinic

Further diabetes follow up for the mother should be arranged at the general
diabetes outpatient clinic.
10
Not Breast Feeding

Women not planning to breast feed can have the insulin infusion discontinued
soon after delivery. The dextrose infusion should be continued for 1 hour without
the insulin.

Blood glucose monitoring pre and 2 hours post prandially should be performed
for 48 hours post delivery aiming for values of 5-7 pre-prandially and 6-10 post
prandially.

Usual diabetes medication should be commenced as soon as the woman is eating
normally.

If blood glucose values are persistently >9mmol/l pre-prandially or >11mmol/l
post-prandially, they may require further treatment and diabetes team will need to
review prior to discharge.

Fructosamine should be checked 5 weeks after delivery so that result is available
in clinic

The mother’s glycaemic control is reviewed at the post natal clinic visit which
should be arranged 6 weeks post delivery.
Diet Treated

Women able to control diabetes with diet alone prior to pregnancy should be able
to return to this.

After delivery the insulin infusion should be stopped and dextrose continued for a
further hour.

Blood glucose monitoring pre and 2 hours post prandially should be performed
for 48 hours post delivery aiming for values of 5-7 pre-prandially and 6-10 post
prandially.

If blood glucose values are persistently >7mmol/l pre-prandially or >10mmol/l
post-prandially, they may require further treatment and diabetes team will need to
review prior to discharge.

The mother’s glycaemic control is reviewed at the post natal clinic visit which
should be arranged 6 weeks post delivery.

Fructosamine should be checked 5 weeks after delivery so that result is available
in clinic
11
MANAGEMENT OF WOMEN WITH IMPAIRED GLUCOSE TOLERANCE IN
PREGNANCY/GESTATIONAL DIABETES
Background






Pregnancy induces a state of insulin resistance which can result in altered glucose
handling during pregnancy.
Impaired glucose tolerance in pregnancy occurs in up to 2-3% of pregnant
women.
Worsening insulin resistance and hyperglycaemia generally becomes evident from
the second trimester onwards.
As with women with diabetes there is an associated increased risk in both
maternal and fetal outcome.
After pregnancy, once the placenta has been delivered blood glucose levels return
to normal in 95% of women with IGT of pregnancy. This figure is slightly lower
in those with gestational diabetes.
There is a 20-50% chance of developing type 2 diabetes in the next 5-10 years.
Screening
Glucose tolerance tests should be performed between 26-28 weeks if any of the following
risk factors are present:

Obese women (BMI >30kg/m2).

Women with a first degree relative with diabetes (sibling, mother, father, child, NOT
husband).

Women with a previous large baby >4.5kg and/or a history of neonatal
hypoglycaemia

Women with a past history of unexplained intra-uterine death in second or third
trimester.

Women with glycosuria (2+ or more, or 1+ on more than one occasion).

Women with previous history of impaired glucose tolerance in pregnancy, treated by
dietary restriction alone.

Other women should be screened on the development of unexplained polyhydramnios
and macrosomia.

Women with polycystic ovarian syndrome.
12

All patients of Indo-Asian origin.

Women with previous gestational diabetes/impaired glucose tolerance which required
insulin therapy during pregnancy should be screened initially at 18 weeks and if
negative again at 26-28 weeks.
Notes

A glucose tolerance test is not necessary in a woman with unequivocal
hyperglycaemia i.e. fasting glucose >7mmol/l or random glucose >11mmol/l on more
than one occasion. They should be referred directly to the joint diabetes antenatal
clinic as soon as possible.

A small number of pregnant women each year present with the classical symptoms
and signs of type 1 diabetes (polydipsia, polyuria, weight loss, hyperglycaemia and
weight loss, as well as occasionally diabetic ketoacidosis). These women require
immediate review and same day referral to the diabetes team. Insulin should be
commenced and will need to be continued post delivery.

A glucose tolerance test is not necessary in women known to have impaired glucose
tolerance prior to pregnancy. They should be referred directly to the joint diabetes
antenatal clinic as soon as pregnancy is confirmed.
13
Oral Glucose Tolerance Test
1) The test is performed in the morning after an overnight fast of 8-14 hours during
which time only water is allowed.
2) After 30 minutes rest, blood is taken for fasting glucose sample in a fluoride
oxalate tube.
3) Patient is given 75g of anhydrous glucose in form of “polycal” liquid to drink


113ml of polycal liquid is measured into a beaker and water added to make up
to a volume of 200ml. The solution is mixed thoroughly.
This solution is to be consumed over a 5 minute period followed by a further
100ml of plain water.
4) A further blood sample for glucose is taken 2 hours after the glucose load (timing
is from the beginning of the drink).
5) During the test the patient is asked to rest and is not allowed anything else to eat
and only water to drink.
Notes



Women should be advised that they need to eat their usual diet in the days leading
up to the test and carry out their usual amount of physical activity.
If the woman is febrile or acutely unwell, the test should be postponed.
Any medication which may interfere with the test should be noted and if possible
stopped 3/7 before test.
Interpretation of Results (Venous Plasma Samples)
Diagnosis of diabetes is based on WHO criteria.
Glucose values taken to represent impaired glucose tolerance are lower than WHO
criteria, to allow for a further increase in glucose values in the subsequent weeks. This
reflects normal practice in diabetes care, and is based on the time when insulin is started.
Diabetes Mellitus:
&/or
Fasting >7.0 mmol/l
2 hour value >11.1 mmol/l
&/or
Fasting 5.6-6.9
2 hour value 8.5-11.1
&
Fasting <5.6 mmol/l
2 hour value <8.5 mmol/l
Impaired Glucose Tolerance:
Normal Glucose Tolerance:
14
Both values have to be in the normal range for a woman to have “normal glucose
tolerance”
Therefore any fasting glucose of ≥5.6 mmol/l or any 2 hour value ≥8.5 mmol/l should
be referred to the joint diabetes antenatal clinic within 1 week.
Antenatal Management of Women with IGT in Pregnancy/Gestational Diabetes

During their first visit relevant history will be taken from the woman and an
explanation of their diagnosis and potential treatment (i.e. either simple dietary
changes or insulin).

The woman will be taught by the diabetic specialist nurse to monitor her own
blood glucose.

Target blood sugars will be 4-6mmol/l before meals and <8 mmol/l 2 hours postprandially.

During the first visit, the woman will be seen by a dietician and receive advice
regarding dietary modification.

During the first visit, the woman should be given the relevant telephone
numbers of the diabetes specialist nurses working in her area and the hospital
diabetes specialist nurses, so she has someone to call for advice.

If the result of the glucose tolerance test is in the diabetic range, she will be
asked to monitor blood glucose values for 3/7 and then call the diabetes
specialist nurse for advice. Arrangements to start insulin at this point can be
made if necessary.

The woman will be reviewed one week later to monitor her blood glucose
values.

If blood glucose values are consistently outside the targets, the woman will be
commenced on insulin. This may be only once daily or up to four times daily
depending on the results with a usual stating dose of 4 units.

The woman will be reviewed 1-2 weekly for the rest of the pregnancy.

Ultrasound scans to assess fetal growth will be carried out every 2-4 weeks.

Method and timing of delivery will depend on obstetric indications, but woman
on insulin are unlikely to go beyond 38 weeks gestation.
15
Management During Labour
Insulin Treated

Any woman who has required insulin during the pregnancy should be treated in
the same was as a woman with type 1 diabetes, using the intravenous regime of
insulin and dextrose described earlier.
Diet Treated

Women who are normally controlled on diet should not require an insulin infusion
in labour.

Blood glucose should be checked 4 hourly.

If the blood glucose > 9mmol/l the intravenous regime of insulin and dextrose
should be commenced.
Postnatal Management
Insulin Treated

Following delivery of the placenta the insulin infusion can be stopped
immediately. The dextrose should continue for a further hour.

Blood glucose monitoring pre and two hours post prandially should be performed
for 48 hours post delivery to ensure a return to normoglycaemia.

If blood glucose values are persistently >6 mmol/l pre-prandially or >8 mmol/l
two hours post-prandially, they may require further treatment and diabetes team
will need to review prior to discharge.

A glucose tolerance test at 5+ weeks post natal should be booked before
discharge.

The mother is reviewed at the post natal clinic visit which should be arranged 6
weeks post delivery (after the glucose tolerance test), with reinforcement of the
dietary and weight advice.
16
Diet Treated

Following delivery blood glucose monitoring pre and 2 hours post prandially
should be performed for 48 hours post-delivery to ensure a return to
normoglycaemia.

If blood glucose values are persistently >6 mmol/l pre-prandially or >8 mmol/l
two hours post-prandially, they may require further treatment and diabetes team
will need to review prior to discharge.

A glucose tolerance test at 5+ weeks post natal should be booked before
discharge.

The mother is reviewed at the post natal clinic visit which should be arranged 6-8
weeks post delivery (after the glucose tolerance test), with reinforcement of
dietary and weight advice.
17
References
Confidential Enquiry into Maternal and Child Health (CEMACH; 2005)
Pregnancy in women with type 1 and type 2 diabetes.
CEMACH, London.
McElduff A et al (2005) The Australasian Diabetes in Pregnancy Society Consensus
guidelines for the management of type 1 and type 2 diabetes in relation to pregnancy.
MJA 183 (7): 373-377.
The Vincent Working Party Report (1996)
Diabetic Medicine 13(4):42-54.
Turner H and Waas J (2002). Diabetes in Pregnancy, Oxford Handbook of Endocrinology
and Diabetes.
Oxford University Press.
WHO (1999) Definition, Diagnosis and Classification of Diabetes Mellitus and its
Complications.
Report of a WHO Consultation Part 1.
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