Gestational Diabetes

Question 1

What is gestational diabetes?

Answer 1

• this is diabetes triggered by pregnancy
• there is reduced insulin sensitivity during pregnancy
• this resolves after birth

Question 2

What is the most significant immediate complication of gestational diabetes?

Answer 2

• a large for dates fetus and macrosomia
• this poses a risk of shoulder dystocia at birth

Question 3

What is the most significant long-term complication of gestational diabetes?

Answer 3

the mother is at higher risk of developing T2DM after pregnancy

Question 4

How is gestational diabetes screened for?

Answer 4

• anyone with RFs should be screened with an oral glucose tolerance test (OGTT)
• this is performed at 24-28 weeks gestation
• women with previous gestational diabetes have their OGTT shortly after booking

Question 5

What are the 5 risk factors that warrant an OGTT?

Answer 5

• BMI > 30
• previous gestational diabetes
• first-degree relative with diabetes
• ethnicity - black Caribbean, Middle Eastern & South Asian
• previous macrosomic baby

macrosomic babies are 4.5kg or more

Question 6

What features suggestive of gestational diabetes warrant an OGTT?

Answer 6

• large for dates foetus
• glucose on urine dipstick
• polyhydraminos

polyhydraminos = increased amniotic fluid

Question 7

How is an OGTT performed?

Answer 7

• it should be performed in the morning following a fast
• they drink a 75g glucose drink
• blood glucose is measured before the glucose drink and after 2 hours

during fasting, they are allowed to drink plain water only

Question 8

What are normal results following an OGTT?

Answer 8

• fasting glucose < 5.6 mmol/l
• glucose after 2 hours < 7.8 mmol / l

results higher than these values suggest gestational diabetes

remember the cutoff values as 5-6-7-8

Question 9

What additional scans are offered in gestational diabetes?

Answer 9

• USS scans are performed every 4 weeks between 28 to 36 weeks gestation
• these monitor fetal growth and amniotic fluid volume

Question 10

What is the management for gestational diabetes when fasting glucose is < 7 mmol/l?

Answer 10

• a trial of control through diet / exercise for 1-2 weeks
• if this is unsuccessful, metformin is given
• if control is still not adequate, there is addition of insulin

Question 11

What is the management for gestational diabetes when fasting glucose > 7 mmol/l?

Answer 11

immediately start insulin +/- metformin

Question 12

What is the management for gestational diabetes when fasting glucose > 6 mmol/l + evidence of macrosomia?

Answer 12

immediately start insulin +/- metformin

this is the case if there are other complications aside from macrosomia too

Question 13

What is a potential option for women who decline insulin / cannot tolerate metformin?

Answer 13

glibenclamide

(a sulfonylurea)

typically, metformin and insulin are the only drugs used in gestational diabetes

Question 14

What advice is given to women about monitoring their blood sugar?

Answer 14

• blood sugar should be monitored several times a day
• target levels are:

fasting:

• 5.3 mmol/L

1-hr post-meal:

• 7.8 mmol/L

2-hr post-meal:

• 6.4 mmol/l

and avoid levels below 4 mmol/l

Question 15

What advice is given to women with pre-existing diabetes prior to conception?

Answer 15

• they should ensure they have good glucose control prior to conception
• they should take 5mg folic acid from preconception until 12 weeks gestation

Question 16

What is involved in the management of pre-existing diabetes in pregnancy?

Answer 16

• insulin is continued in T1DM
• all medications should be STOPPED in T2DM and they should be managed only with metformin +/- insulin

Question 17

What type of screening should be performed in pregnant women with pre-existing diabetes?

Answer 17

retinopathy screening

• performed shortly after booking + at 28 weeks gestation
• there is a high risk of rapid progression to diabetic retinopathy in pre-existing diabetics

this involves referral to an ophthalmologist to check for diabetic retinopathy

Question 18

What type of delivery is advised in diabetic patients?

Answer 18

gestational diabetes:

• birth can occur up to 40 + 6 weeks

pre-existing diabetes:

• a planned delivery is put in place between 37 and 38 + 6 weeks

Question 19

What type of diabetes control is considered for diabetics during labour?

Answer 19

sliding-scale insulin regime

• a dextrose + insulin infusion is titrated to blood sugar evels
• this is for T1DM

AND

• poorly controlled T2DM or gestational diabetes

Question 20

What management is in place for gestational diabetics following birth?

Answer 20

• diabetic medications can be stopped immediately
• a follow up test of fasting glucose is performed after at least 6 weeks

Question 21

What is the management for women with existing diabetes after birth?

Answer 21

• they should lower their insulin doses
• be aware of hypoglycaemia in the postnatal period
• insulin sensitivity increases after birth + with breastfeeding

Question 22

What are babies with diabetic mothers at increased risk of?

Answer 22

• jaundice
• neonatal hypoglycaemia
• polycythaemia
• congenital heart disease
• cardiomyopathy