- All pregnant women should be screened for gestational diabetes unless they are in a low-risk group. (at 28th week)
- Women at high risk for gestational diabetes are those
- >25 years of age;
- those with a body mass index > 25 kg/m2,
- maternal history of macrosomia or gestational diabetes,
- positive diabetes in a first-degree relative;
- high-risk ethnic group (African American, Hispanic, Native American).
- two-step strategy for establishing the diagnosis of gestational diabetes involves
- administration of a 50-g oral glucose challenge with a single serum glucose
measurement at 60 min.
- <7.8 mmol/L (<140 mg/dL) = normal.
- > 7.8 mmol/L (>140 mg/dL) = administration of a 100-g oral glucose challenge
with serum glucose measurements obtained in the
fasting state, and at 1, 2, and 3 h.
- Normal = <5.8 mmol/L (<105 mg/dL), 10.5 mmol/L
(190 mg/dL), 9.1 mmol/L (165 mg/dL), and 8.0
mmol/L (145 mg/dL), respectively.
- Pregnant women with gestational diabetes are at increased risk of:
- preeclampsia,
- delivering infants who are large for their gestational age,
- birth lacerations.
- (after birth) fetuses are at risk of hypoglycemia and birth trauma (brachial
plexus) injury.
--> Treatment of gestational diabetes with a two-step strategy of dietary intervention followed by insulin injections if diet alone does not adequately control blood sugar [fasting glucose < 5.6 mmol/L (<100 mg/dL) and 2-h post-prandial <7.0 mmol/L (<126 mg/dL)] is associated with a decreased risk of birth trauma for the fetus. (Usuaully, most pregnant mothers' glucose levels are controlled by diet modification alone. Compliance to these diet restrictions are usually the culprit for high blood sugar.)
- For women with gestational diabetes, within the 10 years after the index pregnancy there is a 80% (Malaysia) risk of being diagnosed with diabetes. All women with a history of gestational diabetes should be counseled about prevention strategies and have an annual screening for diabetes (according to Malaysian CPG).
- In general, during the first trimester, the initial insulin requirement is 0.7 units/kg per d. By late pregnancy, patients generally require 1 unit/kg per d.
--> Generally, 2/3 of the total insulin dose is given in the morning and 1/3 in the evening. Usually, 2/3 of the morning dose consists of NPH (NPH = Humulin N: intermediate type)and 1/3 of regular insulin. The evening dose consists of half NPH and half regular insulin. Determination of the exact amount of insulin for each pregnant woman is done on a case-by-case basis. Start with the safe amount of insulin units by using the formula above (Usually 1 unit/kg per day), and slowly increase/decrease by 4 units if the blood sugar level results are high/low respectively.
--> Usage of metformin:
- Recent evidence suggests that glyburide or metformin are safe and effective
alternatives. However...
- Fetal, neonatal, and maternal outcomes have been evaluated following maternal
use of metformin for the treatment of GDM and type 2 diabetes. Available
information suggests that metformin use during pregnancy may be safe as long as
good glycemic control is maintained; however, many studies used metformin
during the second or third trimester only.
- Therefore, until further research is done (on the 1st trimesters), treatment
with oral hypoglycemics in Malaysia (and many other countries) is NOT advocated
as the routine 1st line treatment(as it increases the risk of congenital
malformations. ), as Insulin is the drug of choice for the control of diabetes
mellitus during pregnancy.
