Risk of Gestational Diabetes Can Be Predicted Prior to Conception
Gestational diabetes is a pregnancy complication that can increase the risk for preterm delivery and cesarean sections. It occurs in as many as 7% of pregnancies in the United States, particularly in women with certain health conditions such as heart disease and obesity. Researchers from the Kaiser Permanente Division of Research have found that gestational diabetes may be predicted in women, leading to earlier interventions to prevent the condition or better manage symptoms.
A team, led by research scientist Monique Hedderson, studied 580 ethnically diverse women who participated in a multiphasic health checkup during 1984 to 1996. These checkups included health questionnaires and measurements of blood pressure, height, weight, and random serum glucose and cholesterol tests.
For their analyses, the investigators used the following definitions:
• Overweight/obesity: BMI ≥25 kg/m2
• Prehypertension/hypertension: Blood pressure ≥120/80 mm Hg or use of antihypertensives
• Hypercholesterolemia: Total cholesterol ≥200 mg/dL
• Mild hyperglycemia: Pregravid serum glucose 100 to 140 mg/dL
Women who had known risk factors for diabetes and heart disease, such as high blood pressure, high blood sugar and obesity, prior to conception were at greater risk for later developing gestational diabetes. The latter two conditions increased the risk by 4.6 times over normal weight women without elevated blood sugar. Having either prehypertension or hypertension increased the odds by 50%, while having high cholesterol did not increase the risk of gestational diabetes.
While pregravid hyperglycemia (high blood sugar prior to pregnancy) was a stronger predictor of gestational diabetes in computer models, obesity actually had the greatest impact of all factors studied. Hedderson said, “Among gestational diabetes cases, only 9% of the women had pregravid mild hyperglycemia, whereas 44% were overweight or obese…which suggests that, although glucose is a slightly strong risk factor, overweight/obesity is a much more prevalent exposure among gestational diabetes cases."
Other risk factors for gestational diabetes include older maternal age, nonwhite race/ethnicity, previous macrosomic (large) baby, and family history of diabetes.
Having a better understanding of risk factors for gestational diabetes can aid identification of women with an increased risk and target them for interventions, Hedderson concluded.
Women can actually lower their risk for gestational diabetes by obtaining a normal weight prior to conception. A separate study, also performed by researchers at Kaiser Permanente, found that the amount of weight gain after a first pregnancy is associated with the chances of developing the condition during the next one. However, women who lost their “baby weight” after pregnancy had lower odds of gestational diabetes in a subsequent pregnancy. Even just dropping 1 or 2 BMI units, or 10-20 pounds, was found to be a significant risk reducer.
Hedderson MM, et al "Pregravid cardiometabolic risk profile and risk for gestational diabetes mellitus" Am J Obstet Gynecol 2011; DOI:10.1016/j.ajog.2011.03.037.
Ehrlich S, et al "Change in body mass index between pregnancies and the risk of gestational diabetes in a second pregnancy" Obstet Gynecol 2011; DOI: 10.1097/AOG.0b013e31821aa358.