Poor periconceptional diet may increase risk for high glucose levels, gestational diabetes

Women who ate a poor-quality diet before and during early pregnancy had an increased risk for high glucose tolerance test scores and gestational diabetes, according to a presenter at The Pregnancy Meeting.

“Initiatives during pregnancy have focused on lifestyle interventions to limit gestational weight gain,” Gina Milone, MD, a first-year maternal-fetal medicine fellow at the University of California, Irvine, said in her presentation. “While many of these interventions have successfully limited gestational weight gain, this has not consistently translated into improved maternal or perinatal outcomes. This has led investigators to ask the question, ‘Is the prenatal period too late to intervene to see significant improvement? Perhaps, is the periconceptional period a more efficacious window for health behavior change?’”

Milone and colleagues performed a secondary analysis of 9,566 women (mean age, 27.3 years; standard deviation, 6.2; 63.2% white) in the nuMoM2b study — nuMoM2b stands for Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be — whose gestational diabetes mellites (GDM) status was noted. They also analyzed a subgroup of 1,116 women at high risk for GDM who had data available from 3-hour 100 g glucose tolerance tests (GTT) taken at a mean gestational age of 28.7 weeks.

Participants with GTT scores reported their diet for the past 3 months through a food frequency questionnaire, the quality of which was then rated using the Alternative Healthy Eating Index (AHEI)-2010.

Among the patients who had a GDM status noted, the incidence rate of GDM was 4.1%; among those with GTT scores, the incidence rate was 21.3%.

Results from GTTs showed significant differences between AHEI-2010 quartiles for the fasting blood glucose values only, with quartiles three and four — which included patients with the healthiest diets — having lower glucose levels than quartile one.

“Although significant, this difference was modest, with the average fasting glucose level of quartile one being 82, compared to an average of 79 in quartile four,” Milone said.

Looking at continuously represented AHEI-2010 scores, diet quality was inversely associated with blood glucose levels at each GTT measurement.

“For example, looking at the beta coefficient for the 3-hour value tells us that for each one-point increase in AHEI score, the glucose value can be expected to decrease by about 0.22, suggesting that a higher quality diet may be associated with slightly lower glucose values,” she said.

The study’s limitations included its retrospective design, the inclusion of only nulliparous women and the fact that glycemic data were only available for patients at higher risk for GDM, Milone noted.

Moving forward, Milone said public health initiatives targeting an improved periconceptional diet for younger, nulliparous women of lower socioeconomic status should be pursued. As for further research, she suggested studies focus on prepregnancy interventions, long-term outcomes and the association between periconceptional diet and glucose tolerance in a broader population.