Pregnancy causes increase in glucose intolerance. For some women, this can lead to gestational diabetes. In general, insulin requirement of a women increases during pregnancy. Approximately 8.6% of all pregnancy are complicated by gestational
diabetes.
Definition of gestational diabetes (GDM)- The diagnosis of gestational diabetes is based on an oral glucose tolerance test (OGTT) in which a 75g load of glucose is given to the patient.
- GDM is diagnosed if (ADA guidelines 2011)
- Fasting ≥92 mg/dl (5.1 mmol/l)
-
- 1 h ≥180 mg/dl (10.0 mmol/l)
-
- 2 h ≥153 mg/dl (8.5 mmol/l)
When and how to screen for Gestational Diabetes
There has been no
consensus on this issue. The ADA and
RCOG (Jan 2011)
recommends the following:
-
Screen for undiagnosed type 2 diabetes at the first prenatal visit in those with risk factors, using standard diagnostic criteria.
-
In pregnant women not known to have diabetes, screen for GDM at 24–28 weeks of gestation, using a 75-g 2-h OGTT
-
Screen women with GDM for persistent diabetes 6 weeks postpartum.
-
Women with a history of GDM should have lifelong screening for the development of diabetes or prediabetes at least every 3 years.
In Singapore, the MOH reccommends OGTT only for high risk patients early in the pregnancy and at 26-28 weeks
In all other patients urine should be tested for glucose. If glucosuria 1+ or more, plasma glucose levels will be done. OGTT is done if glucose >6.6 more tahn 2 hrs after meal or >7.0 within 2 hrs after meal.
Risk Factors for Gestational Diabetes
- Obesity
- Family history of diabetes
- Medical history of gestational diabetes
- History of large baby more than 4kg
- Previous unexplained stillbirth
- PCOS
- Polyhydramnious
- Twin
Fetal Complications for diabetic women
- Related to glucose levels
- Congenital abnormalities
- Pre-term labour
- Polyhydramnios
- Decrease fetal lung maturity
- Large baby
- Fetal distress and sudden fetal death more common.
- Neonatal Hypoglycemia
Maternal Complications of
Diabetes in pregnancy
- Ketoacidosis (rare)
- Hypoglycemia (too strict control)
- UTI
- Infection: Wound or endometrial
- Hypertension and pre-eclampsia more common,
- Diabetic retinopathy
Management of patients with gestational diabetes
- Close surveillance
- Dietary Control: Maintain fasting glucose at <5.5 mmol/L and 2hr post prandial glucose at <6.7 mml/L
- Metformin and Glibenclamide has been used is oral agents
- Insulin still the safest choice.
- Mothers should monitor fetal movement in last 12 weeks of pregnancy
- Ultrasound for congenital abnormalities at 18-22 weeks
- Fetal growth ultrasound 29-33 weeks
- Non stress cardiotocography with umbilical doppler flow may be considered.
- Screen for hypertension.
- Infants fed early and baby screen for hypoglycemia
- Contraception: OCP in complicated diabetes or infection with IUCD.
