Some Babies Get Bad Start on Obesity Risk From Mom

Babies of mothers who have unhealthy obesity (that is, obesity along with other metabolic comorbidities) appear to have greater levels of adiposity when compared with the offspring of women with metabolically healthy obesity, researchers reported.

At the time of birth, children of mothers with unhealthy obesity weighed an average of 0.62 kg (1.4 lb) more compared with children born to mothers with so-called health obesity (P=0.001), said Emily Flanagan, PhD, a postgraduate researcher at Pennington Biomedical Research Center in Baton Rouge, Louisiana, in a presentation at the ObesityWeek virtual meeting. The findings were also published simultaneously in Obesity.

Flanagan also reported that the children of mothers with unhealthy obesity had 0.27 kg (0.6 lb) more fat mass (P=0.001) and a percentage of fat 5.8% greater (P=0.02) than children of women with healthy obesity.

For the study, she and her colleagues focused on the metabolic conditions in early pregnancy. The team defined the phenotype of mothers with unhealthy obesity according to the National Cholesterol Education Program Adult Treatment Panel III guidelines for metabolic risk.

Unhealthy metabolic risk factors included the following:

• Systolic blood pressure >130 mm Hg or diastolic blood pressure >85 mm Hg

• HDL cholesterol <50 mg/dL

• LDL cholesterol ≥100 mg/dL

• Triglycerides ≥150 mg/dL

• Glucose ≥100 mg/dL

Mothers with two or more of these conditions were considered to have unhealthy obesity. The researchers compared the data for seven women who fit the criteria for unhealthy obesity with those of seven other women with healthy obesity who had none of the risk factors. Flanagan noted that there were also 29 women who had one metabolic risk factor, but these women were excluded from the analysis to avoid ambiguous results.

Women with unhealthy obesity had higher levels of glucose and triglycerides (P<0.001), as well as lower activity energy expenditure, the group found.

Gestational age at delivery and infant age at assessment were similar between the infants born to mothers with unhealthy obesity and those with healthy obesity. Maternal body mass index (BMI), gestational weight gain, and fat accretion also were similar between the two groups of mothers.

The women with healthy obesity gave birth to five boys and two girls; the women with unhealthy obesity gave birth to three boys and four girls, but Flanagan said that the sex of the babies was not a significant factor in the study.

"We are the first, to our knowledge, to show that maternal obesity coupled with risk factors for cardiometabolic disease likely results in prolonged fetal exposure to excess growth-promoting substrates," the researchers wrote. "Future studies should examine the influence of the preexisting maternal metabolic milieu on adverse maternal and infant outcomes on a large scale."

The study identifies a population of women with obesity who are "highly vulnerable to adverse offspring outcomes and highlights the importance for prenatal or preconception interventions that alter the metabolic milieu in this population, who are most at need," the investigators continued. "It is possible that different obesity phenotypes may also need to be considered when evaluating prenatal intervention effects on offspring outcomes. Evaluating metabolic health in conjunction with BMI screening at the start of pregnancy may be clinically relevant to understanding the intergenerational transmission of obesity."

Asked for her perspective, Sharon Zarabi, RD, CDN, a registered dietitian nutritionist at Lenox Hill Hospital in New York City, told MedPage Today: "As obesity rates continue to grow, it will be affecting the outcomes of maternal child health. Nutrients are passed to the fetus through the placenta, so it's important that mommy be vigilant with lifestyle, stress management, and of course food choices."

Weight gain is normal, but the question is how much, how fast, and how much inflammation might be causing metabolic syndrome (i.e., preeclampsia, gestational diabetes, triglyceridemia, etc.), said Zarabi, who was not involved with the study.

"Precision medicine is starting to gain traction, personalizing medicine based on medical evaluation and the body's metabolic system," Zarabi continued. "This includes body fat percentage, lipid panels, glucose curves, insulin levels, which give us a deeper dive than just looking at body mass index and classifying a patient with obesity or overweight."

She said it is important to look further at specific conditions as they impact quality of health. If the mother is consuming an energy-dense diet loaded with the "typical western diet of salt, sugar, and fat -- completely devoid of vitamins and minerals -- how would you expect the fetus to develop? We are a product of what we eat, or in prenatal terms, what we are fed."

She said that obstetricians and gynecologists should be more vigilant with their conversations about health and lifestyle medicine, and encourage "walks, physical activity, and clean eating. The stress of pregnancy can lead to missing out on the most important treatment -- food and movement for optimal outcomes to health for both mommy and baby."

Regarding possible study limitations, Flanagan and co-authors acknowledged the small sample size, which likely limits the observed power. However, they said, the study is strengthened by the "conservative delineation of metabolic phenotypes in women with obesity during early pregnancy and the rigorous measurement of potential confounding variables, including maternal energy intake and expenditure. Our gold standard measures allow us to exclude influence of these variables on infant body composition."

Comment