O&G gestational diabetes

Question 1

Blood glucose targets for gestational diabetes & pre-existing diabetes in Pregnancy

Answer 1

Fasting 5.3 mmol/l
1 hour after meals 7.8 mmol/l, or:
2 hour after meals 6.4 mmol/l

Question 2

Risk factors for gestational diabetes

Answer 2

• BMI of > 30 kg/m²
• previous macrosomic baby weighing 4.5 kg or above
• previous gestational diabetes
• first-degree relative with diabetes
• family origin with a high prevalence of diabetes (South Asian, black Caribbean and Middle Eastern)

Question 3

Screening for gestational diabetes

Answer 3

• theoral glucose tolerance test (OGTT)is the test of choice
• women who’ve previously had gestational diabetes: OGTT should be performed as soon as possible after booking and at 24-28 weeks if the first test is normal. NICE also recommend that early self-monitoring of blood glucose is an alternative to the OGTTs
• women with any of the other risk factors should be offered an OGTT at 24-28 weeks

Question 4

Diagnostic thresholds for gestational diabetes

Answer 4

• fasting glucose is >= 5.6 mmol/L

- 2-hour glucose is >= 7.8 mmol/L

Question 5

Management of gestational diabetes

Answer 5

• newly diagnosed women should be seen in a joint diabetes and antenatal clinic within a week
• women should be taught about self-monitoring of blood glucose
• advice about diet (including eating foods with a low glycaemic index) and exercise should be given
• if the fasting plasma glucose level is< 7 mmol/l a trial of diet and exercise should be offered
• if glucose targets are not met within 1-2 weeks of altering diet/exercise metformin should be started
• if glucose targets are still not metinsulin should be addedto diet/exercise/metformin
• gestational diabetes is treated withshort-acting, not long-acting, insulin
• if at the time of diagnosis the fastingglucose level is >= 7 mmol/l insulin should be started
• if the plasma glucose level is between 6-6.9 mmol/l, and there is evidence of complications such as macrosomia or hydramnios, insulin should be offered
• glibenclamide should only be offered for women who cannot tolerate metformin or those who fail to meet the glucose targets with metformin but decline insulin treatment

Question 6

Management of pre-existing diabetes

Answer 6

• weight loss for women with BMI of > 27 kg/m^2
• stop oral hypoglycaemic agents, apart from metformin, and commence insulin
• folic acid 5 mg/day from pre-conception to 12 weeks gestation
• detailed anomaly scan at 20 weeks including four-chamber view of the heart and outflow tracts
• tight glycaemic control reduces complication rates
• treat retinopathy as can worsen during pregnancy

Question 7

Gestational diabetes definition

Answer 7

New onset hypertension diagnosed after 20 weeks without significant proteinuria.

Question 8

Gestational Hypertension classification

Answer 8

Mild 140-149 mmHg 90-99 mmHg
Moderate 150-159 mmHg 100-109 mmHg
Severe >160 mmHg >110 mmHg

Question 9

Gestational hypertension management

Answer 9

Moderate gestational hypertension does not need to be managed in a hospital setting and patients are normally prescribed oral labetalol. NICE guidelines recommend nifedipine and methyldopa as alternatives to labetalol (e.g. in asthma). Methyldopa is contraindicated in depression.

IV magnesium sulphate is indicated in eclampsia. Lisinopril is an ACE inhibitor and is contraindicated in pregnancy.