Prepregnancy Metabolic Status May Predict Subsequent Gestational Diabetes

Laurie Barclay, MD

October 19, 2010

October 19, 2010 — Metabolic status before pregnancy predicts subsequent gestational diabetes mellitus (GDM), according to the results of a longitudinal cohort study from the Coronary Artery Risk Development in Young Adults (CARDIA) study reported online October 7 in the American Journal of Epidemiology.

"Our study suggests that women may benefit from a focus on care before conception that would encourage screening for metabolic abnormalities before pregnancy, rather than only during pregnancy," said lead author Erica P. Gunderson, PhD, from the Kaiser Permanente Division of Research in Oakland, California, in a news release. "Because weight loss is not advised, and the medication and behavioral treatment options are more limited during pregnancy, the time to prevent gestational diabetes is before pregnancy begins. Screening and treatment of metabolic risk factors before pregnancy to prevent GDM may help reduce its lasting adverse health effects on children, by possibly improving the uterine environment."

The study cohort consisted of 1164 women without diabetes before pregnancy who delivered 1809 live births between 5 consecutive examinations from 1985 to 2006 while enrolled in CARDIA. To calculate the odds of GDM after adjustment for race, age, parity, birth order, and other covariates, the investigators measured cardiometabolic risk factors before pregnancy and performed multivariate repeated-measures logistic regression models.

In only among women with a negative family history of diabetes, the odds ratio of GDM was 4.74 (95% confidence interval [CI], 2.14 - 10.51) for prepregnancy impaired fasting glucose levels (100 - 125 vs < 90 mg/dL), 2.19 (95% CI, 1.15 - 4.17) for moderately elevated fasting insulin levels (> 15 - 20 vs < 10 μU/mL), 2.36 (95% CI, 1.20 - 4.63) for highest insulin levels (> 20 vs < 10 μU/mL), and 3.07 (95% CI, 1.62 - 5.84) for low high-density lipoprotein (HDL) cholesterol levels (< 40 vs > 50 mg/dL; P < .01 for all comparisons).

Low-density lipoprotein (LDL) cholesterol level also was significantly associated with the risk for GDM only among women without a family history of diabetes.

GDM occurred in 26.7% of overweight women with at least 1 cardiometabolic risk factor before pregnancy vs 7.4% of women with no cardiometabolic risk factors before pregnancy.

"Metabolic impairment exists before GDM pregnancy in non-diabetic women," the study authors write. "Interconceptual metabolic screening could be included in routine health assessments to identify high-risk women for GDM in a subsequent pregnancy, and potentially minimize fetal exposure to metabolic abnormalities that program future disease."

Limitations of this study include variable intervals for risk factor measurements before pregnancy and recurrent pregnancies for 20% of women within a single interval. In addition, this study could not determine how well preconception risk factors predicted severity of GDM, because oral glucose tolerance test results during pregnancy were unavailable in CARDIA.

"Measurement of fasting insulin, glucose and HDL-C levels during the postpartum and interconceptual periods (particularly for 30% of US women aged 20-39 yrs who are overweight) is feasible within the current health care system and could identify a high-risk group for subsequent GDM pregnancy," the study authors conclude. "All women with metabolic risk factors could benefit from interventions before and/or during early pregnancy to prevent GDM, and early screening for GDM during pregnancy. Metabolic risk factor screening during the preconception or interconceptual period may also motivate women to modify lifestyle behaviors and provides an opportunity not only to prevent GDM before pregnancy, but to reduce weight retention and central obesity that lead to type 2 diabetes and cardiovascular disease in mid life."

The US National Institutes of Health; the National Heart, Lung, and Blood Institute; the National Institute of Diabetes, Digestive and Kidney Diseases; and the American Diabetes Association supported this study. The study authors have disclosed no relevant financial relationships.

Am J Epidemiol. Published online October 7, 2010.


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