Diagnosed with Gestational Diabetes? You Should Undergo Additional Testing After Delivery

Study Highlights
Title: Postpartum Diabetes after a Gestational Diabetes-Affected Pregnancy
Lead Author: Patricia M. Dietz, PhD, MPH and colleagues
Study Population: 36,251 pregnant patients seeking care at Kaiser Permanente Northwest from 1999-2006
Results: 3.1% (1,127) were diagnosed with gestational diabetes; of those 42% were not tested for diabetes after pregnancy

Overview
An article published by Dietz et al in the October, 2008 edition of the Journal of Obstetrics and Gynecology (1) reported that 42% of women diagnosed with gestational diabetes during their pregnancy did not complete postpartum diabetic testing – either it wasn’t ordered or the women did not undergo testing even though testing was ordered. It is important for women to understand that up to 50% of those diagnosed with gestational diabetes will go on to develop Type 2 diabetes within five years. Long-term, untreated diabetes can result in eye, kidney, blood vessel, heart and nerve damage as well as other ailments.

Women can improve their chances of not developing diabetes if they undertake certain lifestyle modifications such as weight loss to a normal weight (BMI less than 25), dietary changes (like the Mediterranean Diet) and exercise (30 minutes of sweat-producing exercise 5 days per week). Therefore, it has been strongly recommended that if a woman has been diagnosed with gestational diabetes she should undergo another two-hour glucose tolerance test six weeks after delivery. If at that time she is diagnosed with diabetes she should engage a healthcare team and work to lower her blood sugar levels through lifestyle modifications; at first she may also need additional intervention such as oral medication or insulin just to keep her blood sugars controlled. If she does not have Type 2 diabetes, she should still employ the lifestyle changes because she is at risk for developing it.

Definition of gestational diabetes – elevated blood sugars first identified during pregnancy. Most women undergo testing for gestational diabetes between 24 to 28 weeks gestation. Testing may occur earlier in pregnancy if one is considered “high risk” for diabetes. If the initial test is abnormal then a 3-hour glucose tolerance test is ordered. If at least two of the four blood glucose values are elevated, the diagnosis of gestational diabetes is made. Generally, she will visit with a nutritionist and be taught to check her blood sugars at home. Sometimes just changing her diet and increasing exercise is enough to keep her blood sugar levels in the normal range. If not, then either medication or insulin injections will be prescribed.

Postpartum testing – At 6 weeks postpartum those women with a diagnosis of gestational diabetes should undergo a 2 hour test to determine if they have Type 2 diabetes.

Controversy: As published by the US Preventive Services Task Force in May, 2008: Because of a lack of high-quality evidence, it is unknown whether testing for gestational diabetes should be done at all! Does it really improve maternal and neonatal health outcomes? (2) We will not know until better studies have been done. However, since 93% of obstetricians in the United States do test for gestational diabetes, once the diagnosis is made, it is important for women to collaborate with their healthcare providers to optimize their health during and after pregnancy through the various lifestyle modifications.

References
1. Postpartum Screening for Diabetes After a Gestational Diabetes Mellitus-Affected Pregnancy. Dietz PM et al. Obstet Gynecol 2008;112:868–74
2. U.S. Preventive Services Task Force. Screening for Gestational Diabetes Mellitus: U.S. Preventive Services Task Force Recommendation Statement. AHRQ Publication No. 08-05115-EF-2., May 2008. Agency for Healthcare Research and Quality, Rockville, MD.