Obstetric management of GDM
There is no evidence to justify increased surveillance during pregnancy in women with diet-treated gestational diabetes who have no other risk factors. Pregnancy management in women with poorly controlled GDM, previously undiagnosed type 2 diabetes, and those whose fetuses have accelerated growth is similar to that in women with preexisting diabetes. Women with hypertension or whose fetuses are growth restricted should be monitored in the same manner as other pregnancies with such complications.
Principles of Management
The management of pregnancy remains controversial in women with GDM, and all protocols used for prenatal surveillance are empiric.
In women with diet-treated GDM, and in the absence of other risk factors, there are no data to support enhanced as against routine surveillance during pregnancy.
Conversely, pregnancy management should be the same as for women with pre existing diabetes in the following situations:
- Unknown type 2 diabetes discovered during pregnancy
- Women with poorly controlled GDM
- Women whose fetuses have accelerated growth.
At present, it is not known how to perform fetal monitoring: which test is the best? What is the optimal frequency?
Antenatal fetal surveillance including non-stress test and / or fetal biophysical profile is often initiated at 32 weeks and continued until planned delivery at 38 - 39 weeks of gestation. Although some do not recommend tests of fetal well-being before 38 weeks of gestation, unless there is a risk of intrauterine growth restriction.
- Women with hypertension or whose fetuses are growth restricted should be monitored in the same manner as other pregnancies with such complications.
- The routine performance of umbilical artery Doppler has no demonstrated utility in the absence of fetal growth restriction or associated maternal hypertension.
- Monthly ultrasound can be proposed for women with poorly-controlled diabetes or who required insulin.
The routine performance of umbilical artery Doppler has not proved useful in the absence of fetal growth restriction or associated maternal hypertension. Monthly ultrasound can be proposed for women with poorly-controlled diabetes or who require insulin. At present, it is not known how to perform fetal monitoring: which test is the best? What is the optimal frequency?
In women with preterm labor, antenatal steroids for fetal lung maturation are not contraindicated but should be administered with close maternal glucose surveillance and additional insulin if necessary. Beta-mimetic agents should not be used.
The evidence base is limited regarding the timing and the mode of delivery. Women with diet treated GDM whose fetus is growing normally do not require specific intervention unless other risk factors are present. Women with insulin-requiring GDM should be offered elective delivery at 38-39 weeks of gestation.
- Elective cesarean delivery when the estimated fetal weight is > 4250-4500 grams may reduce the risk of shoulder dystocia.
- The relevance of ultrasound weight estimations is limited. No formula has emerged as being superior to the others for the prediction of macrosomia.
- In the presence of suspected macrosomia below these thresholds of estimated fetal weight, earlier induction might be considered.
Maternal glycemic control during labor
Maternal glycemic control during labor can reduce the risk of neonatal hypoglycemia. The aim is to maintain hourly capillary blood glucose between 4 and 7mmol/l (0.72-1.26g/l). Insulin is administered in response to maternal capillary glucose.
^ National Collaborating Centre for Women’s and Children’s Health. Diabetes in pregnancy. Management of diabetes and its complications from pre-conception to the postnatal period. NICE clinical guideline 63 Issue date: March 2008
^ Boulvain M, Stan C, Irion O. Elective delivery in diabetic pregnant women. Cochrane Database Syst Rev 2001; (2):CD001997.