should be discontinued 24 hours before the procedure.
Children having minor surgery lasting less than 2 hours may
stop their metformin on the day of surgery. Metformin
hydrochloride should not be restarted until at least^48 hours
after surgery or after the child is eating again, and only once
normal renal function has been established.h
The manufacturer advises that metformin should also be
omitted if contrast medium is administered during surgery to
reduce the risk of contrast-induced nephropathy. It should
be stopped prior to, or at the time of the test, and not to be
restarted until 48 hours afterwards, and only once normal
renal function has been established.
Use of antidiabetic drugs during medical illness
Manufacturers of some antidiabetic drugs recommend that
they may need to be replaced temporarily with insulin during
intercurrent illness when the drug is unlikely to control
hyperglycaemia (such as coma, severe infection, trauma and
other medical emergencies). Consult individual product
literature.
Diabetes, pregnancy and
breast-feeding 01-Aug-2017
Description of condition
Diabetes in pregnancy is associated with increased risks to
the young woman (such as pre-eclampsia and rapidly
worsening retinopathy), and to the developing fetus,
compared with pregnancy in non-diabetic young women.
Effective blood-glucose control before conception and
throughout pregnancy reduces (but does not eliminate) the
risk of adverse outcomes such as miscarriage, congenital
malformation, stillbirth, and neonatal death.
Management of pre-existing diabetes
gYoung women with pre-existing diabetes who are
planning on becoming pregnant should aim to keep their
HbA 1 c level below 48 mmol/mol ( 6. 5 %) if possible without
causing problematic hypoglycaemia. Any reduction towards
this target is likely to reduce the risk of congenital
malformations in the newborn.
Young women with pre-existing diabetes who are
planning to become pregnant should be advised to take folic
acid at the dose for young women who are at high-risk of
conceiving a child with a neural tube defect, see folic acid
p. 574 .h
Overview
Oral antidiabetic drugs
gAll oral antidiabetic drugs, except metformin
hydrochloride p. 452 , should be discontinued before
pregnancy (or as soon as an unplanned pregnancy is
identified) and substituted with insulin therapy. Young
women with diabetes may be treated with metformin
hydrochloride [unlicensed in pregnancy] as an adjunct or
alternative to insulin in the preconception period and during
pregnancy, when the likely benefits from improved blood-
glucose control outweigh the potential for harm. Metformin
hydrochloride can be continued immediately after birth and
during breast-feeding for those with pre-existing Type 2
diabetes. All other antidiabetic drugs should be avoided
while breast-feeding.h
Insulin
Limited evidence suggests that the rapid-acting insulin
analogues (insulin aspart p. 455 and insulin lispro p. 456 ) can
be associated with fewer episodes of hypoglycaemia, a
reduction in postprandial glucose excursions and an
improvement in overall glycaemic control compared with
regular human insulin.
gIsophane insulin p. 457 is thefirst-choice for long-
acting insulin during pregnancy, however in young women
who have good blood-glucose control before pregnancy with
the long-acting insulin analogues (insulin detemir p.^459 or
insulin glargine p. 459 ), it may be appropriate to continue
their use throughout pregnancy.
Continuous subcutaneous insulin infusion p. 454 (insulin
pump therapy) may be appropriate for young women who
have difficulty achieving glycaemic control with multiple
daily injections of insulin without significant disabling
hypoglycaemia.
All young women treated with insulin during pregnancy
should be aware of the risks of hypoglycaemia, particularly in
thefirst trimester, and should be advised to always carry a
fast-acting form of glucose, such as dextrose tablets or a
glucose-containing drink. Pregnant young women with Type
1 diabetes should also be prescribed glucagon p. 465 for use
if needed.
Young women with pre-existing diabetes treated with
insulin during pregnancy are at increased risk of
hypoglycaemia in the postnatal period and should reduce
their insulin immediately after birth. Blood-glucose levels
should be monitored carefully to establish the appropriate
dose.h
Medication for diabetic complications
gAngiotensin-converting enzyme inhibitors and
angiotensin-II receptor antagonists should be discontinued
and replaced with an alternative antihypertensive suitable
for use in pregnancy before conception or as soon as
pregnancy is confirmed. Statins should not be prescribed
during pregnancy and should be discontinued before a
planned pregnancy.hGestational diabetes
gYoung women with gestational diabetes who have a
fasting plasma glucose below 7 mmol/litre at diagnosis,
shouldfirst attempt a change in diet and exercise alone in
order to reduce blood-glucose. If blood-glucose targets are
not met within^1 to^2 weeks, metformin hydrochloride p.^452
may be prescribed [unlicensed use]. Insulin p. 454 may be
prescribed if metformin is contra-indicated or not
acceptable, and may also be added to treatment if metformin
is not effective alone.
Young women who have a fasting plasma glucose above
7 mmol/litre at diagnosis should be treated with insulin
immediately with or without metformin hydrochloride, in
addition to a change in diet and exercise.
Young women who have a fasting plasma glucose between
6 and 6. 9 mmol/litre alongside complications, such as
macrosomia or hydramnios, should be considered for
immediate insulin treatment, with or without metformin
hydrochloride.
Young women with gestational diabetes should
discontinue hypoglycaemic treatment immediately after
giving birth.hUseful Resources
Diabetes in pregnancy: management from preconception to
the postnatal period. National Institute for Health and Care
Excellence. Clinical guideline NG 3. February 2015.
http://www.nice.org.uk/guidance/ng 3BNFC 2018 – 2019 Diabetes mellitus 451
Endocrine system6