Case 73: Diabetes in pregnancy

 

Case 73: Diabetes in pregnancy

CASE 73: DIABETES IN PREGNANCY

History

A 20-year-old woman is pregnant for the first time. The pregnancy is unplanned and the

partner has left but she is supported by her mother and has decided to continue.

She was diagnosed with type 1 diabetes at age 15 years. She has been taking long-acting and

short-acting insulin under the care of her general practitioner (GP), but the referral letter

suggests that she has not always been compliant.

She had a positive pregnancy test 2 weeks ago and her GP has referred her urgently to the

antenatal clinic for review in view of the diabetes. By her dates she is now 7 weeks and 5 days’

gestation. She has no other significant gynaecological or medical history.

Examination

The woman has a body mass index of 29 kg/m2. Blood pressure is 131/68 mmHg and pulse

is 81/min.

INVESTIGATIONS

Normal range

Haemoglobin (Hb)A1c 7.8% <7.0%

Urinalysis: glucose ++

Questions

• What further investigations need to be arranged?

• Outline the principles of management of the pregnancy.100 Cases in Obstetrics and Gynaecology

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ANSWER 73

The investigations can be divided into those for maternal and for fetal wellbeing:

• Maternal wellbeing:

• baseline urea and electrolytes

• pre- and postprandial capillary blood glucose measurements

• retinal assessment if not performed in last 12 months.

• Fetal wellbeing:

• viability scan (increased risk of miscarriage in diabetic women)

• fetal echocardiography (increased risk of all fetal abnormalities in diabetic offspring)

• detailed anomaly ultrasound examination at 20 weeks

• regular third-trimester growth scans.

Diabetic (type 1) pregnancies may be affected by an increase in a range of complications as

well as fetal abnormalities. However optimal control of blood sugar is thought to reduce the

complication risk to near that of a non-diabetic pregnancy, so a large proportion of management is aimed at maintaining very tight blood glucose control. In this particular case, the

history, HbA1c and presence of glycosuria suggest that the woman has generally poor control,

providing a particular challenge to management of this pregnancy.

! Management principles in maternal insulin-dependent diabetes

• Antenatal:

• immediate change to an increased insulin-dosing regime using more frequent doses to adapt to the increasing demand in pregnancy

• aim to keep fasting blood glucose between 3.5 and 5.9 mmol/L and 1 h postprandial blood glucose below 7.8 mmol/L throughout the pregnancy

• advise women of the risk of hypoglycaemia and hypoglycaemia unawareness

in pregnancy

• multidisciplinary care with endocrinologist/diabetologist, dietitian, specialist diabetic nurse, obstetrician and midwife with special interest in diabetic

pregnancies

• full hospital care with regular review, usually every 2 weeks, or more frequently if control remains poor

• increase in insulin requirements expected throughout the pregnancy

• regular ultrasound assessment from 28 weeks for fetal growth and liquor

volume, in view of the risk of macrosomia and polyhydramnios, secondary

to fetal hyperinsulinaemia

• consideration of induction of labour at 38 weeks to reduce the risk of sudden

stillbirth.

• In labour:

• sliding-scale insulin regime in labour (or during caesarean section)

• aim for vaginal delivery unless contraindicated by obstetric factors.

• Postnatal:

• early blood glucose checks and feeding of the baby in view of its hyperinsulinaemic state

• reduction of maternal insulin regime to the pre-pregnancy regime immediately after delivery.Case 73: Diabetes in pregnancy

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KEY POINTS

• Type 1 diabetes pregnancies are high risk for mother and fetus and need specialist

diabetes and obstetric input. Very close blood glucose control should reduce the

complication rate to near that of a non-diabetic mother.

• Fetal complications include miscarriage, congenital abnormality, macrosomia,

stillbirth and shoulder dystocia.