Diabetes Mellitus: Management of Pre-existing Diabetes Mellitus in Pregnancy CPG

• Pre-pregnancy counselling

• First visit in pregnancy

• Subsequent Visits in Pregnancy

• Delivery

• Management of Hypoglycaemia (clinical algorithm)

Pre-pregnancy counselling

Specific diabetes related measures

• the clear benefits of optimal metabolic control in reducing the risk of congenital malformations

• the clear benefits of optimal metabolic control in reducing the risk of an unhealthy baby

• an outline of routine management expectations during pregnancy including glycaemic targets; pregnancy should be delayed until HbA1c <8.0%

• advice about contraception until conception is desired

General pre-pregnancy obstetric advice

• Folate supplements 5 mg/day

• Not smoking

• Reduced alcohol intake

• Review all medications (including complementary) for safety in pregnancy

• Check rubella and varicella immune status

• Pap smear if not performed within last 2 years

• FBE, blood group and antibodies

• TFT, Thyroid antibodies, Coeliac disease screen for Type 1

Specific

• When conception is anticipated more direct action is required

Medications

• Oral hypoglycaemic agents are contraindicated during pregnancy. Women with pre-existing diabetes treated with oral agents should ideally be converted to insulin prior to conception.

• In special circumstances, oral agents may be of more benefit than no therapy at all.

• Antihypertensive therapy should be optimised for pregnancy. Drugs contraindicated in pregnancy should be changed prior to conception to avoid loss of BP control in early pregnancy.

• Lipid lowering therapy must be ceased.

Education

• Formal review by a diabetes educator and a dietitian, with the goal of ensuring adequate self-management skills including sick day care. Hypoglycaemia management must be reviewed, including glucagon use by the partner. Suggestion for dealing with morning sickness could be discussed.

Complications review

• Nephropathy - a timed urine sample and serum creatinine to quantify the microalbumin excretion rate and creatinine clearance

• Retinopathy- refer to ophthalmologist for an eye examination conducted through dilated pupils if not performed in the last 12 months. Retinopathy requiring treatment should be dealt with prior to pregnancy.

• Consider the possibility of macrovascular disease and formally investigate if a possibility.

Miscellaneous

• Thyroid and renal (electrolytes, urea, creatinine and uric acid) function should be measured

• Screen for coeliac disease if not previously done (total IgA, anti-gliadin and anti-transglutaminase antibodies)

• Establish a plan for very early review when pregnancy is confirmed

Contraindications to pregnancy

• The medical role is to advise women of the risks they run in undergoing a pregnancy. The decision is the woman's (couple's).

• Poor glycaemic control HbA1c > 8.0% until corrected.

• Active proliferative retinopathy until treated.

• Severe nephropathy creatinine >/= 0.25 mmol/L

• Macrovascular disease

First Visit in Pregnancy

General pregnancy measures

• Perform routine antenatal screening tests, including MSU for microscopy and culture

• Provide advice about treatment of nausea and vomiting in pregnancy

• Perform Pap smear if not done in last 2 years

Diabetes related measures

• Repeat steps for pre-pregnancy councelling

• Glycaemic control

Screening for fetal anomalies/ aneuploidy

• Midtrimester maternal serum screening is not reliable in pre-pregnancy diabetes. These patients should be offered combined first trimester screening for aneuploidy with HCG and PAPP-A measured at 10 weeks and an ultrasound examination for dating, nuchal translucency, gross morphology and plurality at 12 weeks.

Subsequent Visits in Pregnancy

• Patients should see the ophthalmologist each trimester

• Ultrasound examination for morphology at 19 weeks.

• Ultrasound examination for growth at 28-30 weeks and 34-36 weeks. More frequent ultrasound examination, including umbilical artery blood flow measurement, may be indicated with the following complicating factors:

Delivery

Timing

• Patients with optimal glycaemic control and no complicating factors (see above) should be delivered at 40 weeks, with the method depending on obstetric factors. If an elective caesarean section is to be performed, it should be at 39 weeks.

• Patients with one of the complicating factors mentioned above should be delivered at 38-39 weeks, or earlier if indicated. Elective caesarean section should be performed at 38 weeks.

• If delivery before 36 weeks is indicated, Betamethasone to promote fetal lung maturity should be administered if possible. This will usually require admission for sliding scale insulin.
  
  

Method

• If the estimated fetal weight at the time of delivery is < 4,000 g, vaginal delivery is usually appropriate unless there are other obstetric indications for caesarean section.

• If the estimated fetal weight at the time of delivery is > 4,250 g, elective caesarean section should be strongly considered because of the risk of shoulder dystocia.

• If the estimated fetal weight at the time of delivery is 4,000 - 4,250 g, the decision about the route of delivery should be discussed with the patient taking into account the risks for the particular patient.

• Management of Hypoglycaemia (clinical algorithm)