Case 21 A 24-year-old insulin-dependent diabetic woman planning a pregnancy

Case 21 A 24-year-old insulin-dependent

diabetic woman planning a pregnancy

Ms Kumar is a 24-year-old known to have type 1 insulindependent diabetes mellitus (IDDM) since the age of 15

years. She is in a stable relationship and wishes to start a

family.

What prepregnancy advice and care

would you offer her?

Offer prepregnancy counselling and care by a multidisciplinary team (combined obstetric and diabetic clinic) as

good control of diabetes and lower HbA1c levels lower

the risk of congenital malformations in the fetus and are

associated with improved pregnancy outcome.

Review her medication and intensify her hypoglycaemic therapy to aim for HbA1c <6.1%.

Advise continuation or commencement of contraception until good glycaemic control is achieved (HbA1c

<6.1%) as the risk of congenital malformations with

levels >10% can be as high as 25%. Carry out monthly

measurement of HbA1C and increase the frequency

of self - monitoring of blood glucose. The aim is for a

blood glucose level of 4 – 7 mmol/L before and during

pregnancy.

Prescribe 5 mg/day folic acid prepregnancy and continue until 12 weeks ’ gestation. Check her rubella immunity status.

Offer her dietary advice. Encourage her to eat a diet

with high levels of complex carbohydrates, soluble fibre

and vitamins and reduced levels of saturated fats. Advise

her on how to lose weight if her BMI is >27 kg/m2 and

also give general advice such as smoking cessation and

reducing alcohol intake.

Carry out a retinal and renal assessment by way of

fundoscopy, urine microalbuminuria and renal function

tests. The risk of pre - eclampsia is increased with the presence of microalbuminuria or proteinuria.

Reinforce the idea that she will require additional time

and effort to manage her diabetes in pregnancy and

encourage frequent contact with health care professionals. The risk of diabetes in her child would be around

2 – 3%.

Ms Kumar’s HbA1c is 13% with high fasting and

postprandial sugars. She has no ketones or protein in her

urine. She is immune to rubella and the renal function tests

are normal. There is no evidence of retinopathy. She is on

enalapril for hypertension, which is changed to methyldopa.

She is advised to continue the progesterone-only pill until

the blood sugar levels are optimized and HbA1c <6.1%.

Lifestyle advice is also given. A follow-up visit in 3 months’

time shows good glycaemic control with normalization of

HbA1c. She stops the contraceptive pill and hopes to

conceive soon. She is taking 5mg folic acid.

Angiotensin converting enzyme (ACE) inhibitors

should be stopped before or soon after confirming pregnancy as they may cause oligohydramniosis, renal failure

and hypotension in the fetus. Retinopathy should be

treated prior to pregnancy.

Women with glomerular filtration rates <45 mL/min

and/or proteinuria >5 g/day during pregnancy should be

offered consultation with a nephrologist. Pregnancy in

women with severe nephropathy should be discouraged

because of the poor outcome associated with it both to

the women and the fetus.

Ms Kumar asks about the effects of diabetes on pregnancy

and the fetus and also the effects of pregnancy on diabetes.

How would you counsel her in

this regard?

Effects of pregnancy on diabetes

Increasing doses of insulin would be required as pregnancy progresses because of physiological insulin resistance and decreased glucose tolerance as a result of

anti - insulin hormones secreted by the placenta.

Obstetrics and Gynaecology: Clinical Cases Uncovered.

By M. Cruickshank and A. Shetty. Published 2009 by Blackwell

Publishing. ISBN 978-1-4051-8671-1.Case 21 139

PART 2: CASES

During pregnancy, hypoglycaemic unawareness and

severe hypoglycaemia are common and diabetic ketoacidosis can develop more rapidly. Diabetic retinal and renal

disease can deteriorate during pregnancy.

The incidence of worsening chronic hypertension or

pregnancy - induced hypertension and/or pre - eclampsia

is high (varying from 40% to 73% across series) in

women with both incipient and overt nephropathy.

Effects of diabetes on pregnancy

There is an increased likelihood of:

• Pre - eclampsia

• Macrosomia, polyhydramnios and shoulder dystocia

• Caesarean section, operative vaginal delivery

• Worsening nephropathy and superimposed pre -

eclampsia resulting in an increase in iatrogenic preterm

delivery

• Infections

Box 21.1 Classification of diabetes complicating

pregnancy

• Pregestational

• Type 1 (insulin-dependent)

• Type 2 (non-insulin-dependent)

• Gestational diabetes

Box 21.2 White’s classification of type 1 diabetes

Class Age of onset (years) Duration (years) Vascular disease Therapy

A Any Any None A1-diet only

B Over 20 <10 None Insulin

C 10–19 10–19 None Insulin

D Before 10 >20 Benign retinopathy Insulin

F Any Any Nephropathy Insulin

R Any Any Proliferative retinopathy Insulin

H Any Any Heart disease Insulin

Box 21.3 Gestational diabetes mellitus

Definition

Carbohydrate intolerance of variable severity with onset or

first recognized during the present pregnancy. This definition

will include women with abnormal glucose tolerance that

reverts to normal after delivery, and a small number of

women with undiagnosed type 1 or type 2 diabetes

Screening for gestational diabetes in women

with risk factors is recommended if

• BMI >30kg/m2

• Previous macrosomic baby >4.5kg

• Previous gestational diabetes

• Family history of diabetes (first degree relative with type 1

or type 2 diabetes)

• Women from high risk ethnic group – South Asian,

Afro-Caribbean, Chinese

Diagnosis of gestational diabetes

In women with risk factors, a 2-hour 75g oral glucose

tolerance test at around 24–28 weeks should be used to

diagnose GDM. If there has been a previous history of

GDM, an OGTT at 16–18 weeks, and if normal, repeated

again at 28 weeks is recommended. The criteria

recommended for diagnosis of GDM are fasting venous

plasma glucose >5.5mmol/L or >9mmol/L 2 hours after

OGTT

A diagnosis of GDM identifies women at increased risk

of developing type 2 diabetes in future140 Part 2: Cases

PART 2: CASES

Effects of diabetes on the fetus and neonate

There is an increased likelihood of:

• Congenital malformation – the risk is related to the

glycaemic control around the time of conception and

directly related to the level of HbA1c. Sacral agenesis is a

specific congenital abnormality associated with diabetes.

Congenital heart defect, skeletal abnormalities and neural

tube defects are also more common.

• Spontaneous miscarriage.

• Unexplained fetal death in utero, highest after 36 weeks

resulting from hypoxia in the presence of hyperglycaemia

and lactic acidosis.

• Perinatal and neonatal mortality (increased by 5 - to

10 - fold).

• Macrosomia, defined as birth weight >4.5 kg or >90th

centile for gestational age (seen especially with poor

diabetic control).

In the neonate:

• Respiratory distress syndrome

• Hypoglycaemia

• Polycythaemia and jaundice

• Hypocalcaemia and hypomagnesaemia

• Hypertrophic cardiomyopathy

testing strips and advice regarding testing for ketonuria

or ketonaemia if hyperglycaemic or unwell should be

offered.

Twice - daily mixed short - acting and intermediate -

acting insulin should be changed to a four times daily

basal bolus regimen (three premeal injections of fast

acting insulin and nocturnal intermediate acting insulin)

as it allows maximum flexibility in altering insulin dosage

to compensate for the increased requirements of pregnancy and is also associated with fewer instances of neonatal and maternal hypoglycaemia.

Those with Type 2 diabetes require treatment with

insulin even if well - controlled with oral hypogylcaemics.

Conversion to insulin could be carried out either before

or in early pregnancy. Oral hypoglycaemics (both sulphonylureas and biguanides) are traditionally avoided in

pregnancy because they cross the placenta and there is a

theoretical risk of fetal hypoglycaemia. However, there is

some evidence that continuing metformin in pregnancy

may be beneficial.

Women with diabetes who are pregnant should be

offered early referral to a joint diabetes and antenatal

clinic (Box 21.4 ).

Ms Kumar sees her GP with 9 weeks’ amenorrhoea and is

delighted to have a positive pregnancy test. The GP refers

her to the combined obstetric and diabetic clinic for a

booking visit.

How would you manage her at the

booking visit?

• Confirm viability of pregnancy and gestational age by

ultrasound

• Offer information, advice and support for optimizing

glycaemic control

KEY POINT

Gestational diabetes mellitus (GDM) is associated with

increased perinatal mortality and morbidity, but to a lesser

degree than pre-existing diabetes.

There is no increased risk of congenital abnormality rate

except in those with hyperglycaemia in first trimester or

unrecognized diabetes predating pregnancy.

GDM is associated with an increased risk of macrosomia

and pre-eclampsia.

Ms Kumar also wishes to know the target blood glucose

ranges for pregnancy.

The target range to aim for during pregnancy is a fasting

blood glucose between 3.5 and 5.9 mmol/L and 1 - hour

postprandial blood glucose <7.8 mmol/L during

pregnancy.

She should be advised of the risks of hypoglycaemia

and the difficulties in always being aware of this in pregnancy, particularly in the first trimester. She should be

provided with glucagon injections and herself and her

partner and family should be instructed in its use. Ketone

Box 21.4 Medical management of gestational

diabetes

• Management with diet initially with reduced fat,

increased fibre and regulation of carbohydrate intake

• If, after nutritional advice, pre- and postprandial glucose

levels are normal and there is no evidence of excessive

fetal growth, manage as a normal pregnancy

• Intensive management with diet and/or insulin if

macrosomia is suspected or if blood glucose levels are in

the range for established diabetes

• Newer sulphonylureas and metformin may be used as

alternatives to insulin in GDMCase 21 141

PART 2: CASES

• Take a clinical history to establish the extent of diabetes - related complications

• Review medications for diabetes and its

complications

• Offer retinal and renal assessment if these have not

been undertaken in the previous 12 months

• Discuss antenatal screening tests

Ms Kumar has a normal booking scan which shows a single

intrauterine live pregnancy of 10 weeks’ gestation. She

wishes to undergo mid-trimester serum screening for

Down’s syndrome. Her glycaemic control is optimal with

normal HbA1c levels. Both retinal assessment and renal

function tests are normal. Her blood pressure is

130/80mmHg on 250mg methyldopa twice daily. There is

no proteinuria or ketonuria.

Regular growth scans every 4 weeks from 28 weeks

onwards, to detect macrosomia and polyhydramnios is

advised. Detailed retinal examination in early pregnancy

and at least once in each trimester thereafter according

to the severity of any retinopathy detected is also advised.

Women with nephropathy require regular monitoring

of renal function (serum urea creatinine) and quantification of proteinuria (24 - hour protein excretion,

protein : creatinine ratio).

Her serum screening for Down’s syndrome is low risk. The

anomaly and the fetal cardiac scan are normal. Glycaemic

control remains optimal. She presents at 29 weeks with

painful contractions every 3–4 minutes. Abdominal

examination confirms the fetus to be cephalic, the uterus to

be non-tender and the uterine contractions strong every 1–3

minutes. The cardiotocogram (CTG) is normal. Vaginal

examination shows the cervix to be 1cm long, 1cm dilated

and soft. There are no symptoms of urinary tract infection

and the urine dipstick test is normal.

What is your diagnosis and how would

you manage her?

The diagnosis is preterm labour. She would need a mid -

stream specimen of urine (MSSU) for culture and sensitivity, high vaginal swab (HVS), full blood count (FBC),

C - reactive protein (CRP) and urea and electrolytes

(U & E).

Steroids (12 mg betamethasone, 24 hours apart) for

fetal lung maturation would be indicated, and tocolysis

with atosiban (see Case 19 ) should be considered to allow

for completion of the course of steroids. Additional

insulin cover either by way of a sliding scale or subcutaneous insulin, according to an agreed protocol, is indicated as both steroids and atosiban can worsen glycaemic

control.

She receives both the doses of betamethasone IM. All

investigations are normal. The contractions settle and she is

discharged home after 3 days in hospital. For the rest of the

pregnancy her glycaemic control remains good and BP well

controlled with methyldopa. Induction of labour is planned

for 38 weeks + 5 days’ gestation.

KEY POINT

An insulin sliding scale should be started at the onset of

spontaneous labour, prior to caesarean section or when

glycaemic control is difficult to maintain (e.g. while

receiving steroids or atosiban).

An infusion of 500mL 10% glucose with 10mmol KCL,

is commenced at 100mL/hour via a controlled infusion

pump. An intravenous insulin infusion, 50 units Humulin

soluble insulin made up to 50mL with normal saline, is

started at an initial rate of 2 units/hour (2mL/hour) by

syringe pump.

Blood glucose is measured regularly using blood glucose

measuring strips with the aim of maintaining it at

4–7mmol/L by varying the insulin infusion rate.

KEY POINT

Plan delivery by way of induction or caesarean section

between 38 and 39 weeks, although in well-controlled

diabetes, in the absence of macrosomia or hypertension,

the pregnancy may be allowed to progress to 40 weeks.

Pregnancy should not be allowed to continue beyond 40

weeks in women with pre-existing diabetes.

If GDM is well controlled with normal fetal growth,

await spontaneous labour.

Ms Kumar is induced with vaginal prostaglandin E2. She

then has an artificial rupture of membranes followed by

Syntocinon augmentation. The fetus is monitored with

continuous CTG.

How would you manage her in labour?

Commence an insulin sliding scale from the onset of

established labour. Monitor capillary blood glucose on an

hourly basis and aim to maintain this between 4 and

7 mmol/L.142 Part 2: Cases

PART 2: CASES

Ms Kumar has an emergency lower segment caesarean

section for failure to progress at 7cm. The baby weighs

4.2kg with a good Apgar score. The procedure is

uncomplicated, with a blood loss of 470mL.

What would be the postpartum

management?

The rate of insulin infusion should be halved following

delivery of the placenta, as her requirements for insulin

reduce postpartum. Once she is eating normally, subcutaneous insulin should be recommenced at the prepregnancy dosage.

The baby should be fed as soon as possible after birth

(within 30 minutes) and then at frequent intervals (2 – 3

hours) until feeding maintains blood glucose levels

>2.0 mmol/L. The baby should have blood glucose testing

after feeding to rule out neonatal hypoglycaemia.

Ms Kumar makes a good postnatal recovery. She is

commenced on her prepregnancy dosage of insulin with

which her sugars are well controlled. Both mother and baby

are discharged on day 5 postoperatively and a follow-up

appointment arranged for the diabetic clinic. She has a

Depo-Provera injection for contraception before discharge.

KEY POINT

In women with GDM on insulin, following delivery of

placenta, the insulin should be stopped. Women with

GDM should undergo formal 75g oral glucose tolerance

test (OGTT) 6 weeks following delivery to exclude diabetes

present outside of pregnancy. They should be counselled

regarding the risks of future diabetes and receive lifestyle

advice concerning exercise, diet and reduced fat intake.

CASE REVIEW

Ms Kumar, who had IDDM, presented appropriately to the

prepregnancy clinic for advice which gave an opportunity

to optimize her glycaemic control, stress the importance of

optimizing glucose control and its effects on the fetus and

pregnancy. The antihypertensive enalapril was stopped and

was replaced with methyldopa. Folic acid 5 mg was also

started. Prepregnancy renal function and retinal examination were also performed. She came off contraception and

conceived once the HbA1c was normalized.

Antenatal care was in the combined clinic where she was

seen by a team comprising a diabetologist, obstetrician,

dietitian, diabetic nurse and midwife. Antenatally, she

required increasing doses of insulin with very good

glycaemic control. She had regular growth scans which

showed fetal growth to be on the 95th centile with

polyhydramnios.

Labour was induced at 38+ weeks. She was commenced

on insulin sliding scale in established labour to maintain

her blood sugars. As a result of failure to progress in labour,

an emergency lower segment caesarean section was performed. The sliding scale continued until she could eat

following the caesarean section, when she went back on to

her prepregnancy regimen of insulin.Case 21 143

PART 2: CASES

ObGyncases (Healthcare Touch)

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Case 21 A 24-year-old insulin-dependent diabetic woman planning a pregnancy

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