News
We know from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study that what were formerly considered mild and inconsequential maternal blood glucose levels are instead potentially quite harmful. The study showed a clear linear relationship between maternal fasting blood glucose levels, fetal cord blood insulin concentrations (a reflection of fetal glucose levels), and newborn body fat percentage (N. Engl. J. Med. 2008;358:1991-2002).
Interestingly, Dr. Patrick Catalano’s analysis of data from the HAPO study (Diabetes Care 2012;35:780-6) shows us more: Maternal obesity is almost as strong a driver of newborn obesity as is GDM. Compared with GDM (which increased the percentage of infant birthweights to greater than the 90th percentile by a factor of 2.19), maternal obesity alone increased the frequency of LGA by a factor of 1.73, and maternal obesity and GDM together increased LGA newborns by 3.62-fold.
In light of these recent findings, it is critical that we not only treat our patients who have GDM, but that we attempt to interrupt the chain of obesity that passes from mother to fetus, and from obese newborns onto their subsequent offspring.
A growing proportion of women across all race and ethnicity groups gain more than 40 pounds during pregnancy for singleton births, and many of them do not lose the weight between pregnancies. Increasingly, we have patients whose first child may not have been exposed to obesity in utero, but whose second child is exposed to overweight or obesity and higher levels of insulin resistance and glycemia.
The Institute of Medicine documented these issues in its 2009 report, "Weight Gain During Pregnancy: Reexamining the Guidelines." Data on maternal postpartum weights are not widely available, but data that have been collected suggest that gaining above recommended ranges is associated with excess maternal weight retention post partum, regardless of prepregnancy BMI. Women who gained above the range recommended by the IOM in 1990 had postpartum weight retention of 15-20 pounds. Among women who gained excessive amounts of weight, moreover, more than 40% retained more than 20 pounds, according to the report.
We must break the intergenerational transfer of obesity and insulin resistance by liberally treating GDM and optimizing glucose control during pregnancy. More importantly, we must emphasize to women the importance of having healthy weights at the time of conception. Recent research affirms that moderately simple interventions, such as dietary improvements and exercise can go a long way to achieving these goals. If we don’t – in keeping with the knowledge spurred on by Dr. Barker – we will be programming more newborns for life with insulin resistance, obesity, and disease.
Dr. Moore is a perinatologist who is chair of the department of reproductive medicine at the University of California, San Diego. He said he had no relevant financial disclosures.