Obesity/Diabetes in Pregnancy Affects Even Normal Babies

Liam Davenport

May 12, 2016

Maternal gestational diabetes mellitus and excessive weight gain during pregnancy are associated with a significantly increased risk of childhood overweight and obesity, even in normal-weight offspring, say US researchers.

In one of the largest studies to date of the relationship between maternal factors and childhood obesity, they found that gestational diabetes increased the risk of obesity in the first 10 years of life of the child by almost 30%, while excessive gestational weight gain increased the risk by over 15%.

Lead author Teresa A Hillier, MD, MS, an endocrinologist and senior investigator at the Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon, said that the next step will be to perform intervention studies to see if controlling maternal weight gain and hyperglycemia could help prevent childhood obesity.

However, she told Medscape Medical News, given that around half of women in the United States already exceed the pregnancy weight gain guidelines, intervention to encourage normal weight gain "is the right thing to do while we await that research."

Dr Hillier said that the "bottom line" is that there are few opportunities to intervene with women before they become pregnant. "They come as they are, if you will, when they are pregnant — whether that's normal weight, overweight, or obese.

"The good news about our study is that we're seeing risk factors that are definitely modifiable during pregnancy to impact long-term overweight and obesity in the child," she added.

"That is clinically very inspiring, to me as an epidemiologist in prevention, that there is potential to intervene once they present to the clinic pregnant to help them manage their weight gain and their blood sugars, if they're elevated."

The research was published online in the Maternal and Child Health Journal on May 6.

Does Maternal Obesity or Diabetes in Pregnancy Affect Normal-Weight Babies?

Explaining the genesis of the work, Dr Hillier noted that previous studies have shown that both high- and low-birth-weight babies are at increased risk of becoming obese and developing diabetes.

And the assumption has always been that "normal"-birth weight babies are metabolically normal.

"We wondered if there were differences among normal-birth-weight babies based on what happened in pregnancy," she explained.

Her team therefore studied 24,141 mothers and their normal-weight offspring, born between 1995 and 2003, from the northwest of mainland United States and Hawaii. All women had undergone testing for gestational diabetes, consisting of a 50-g glucose-challenge test and, if that was positive, a 3-hour 100-g oral glucose tolerance test.

For the 13,037 full-term children who began life with a normal birth weight, annual height and weight measurements were collated to determine gender-specific body mass index-for-age percentiles based on the US Centers for Disease Control and Prevention criteria, using the normative reference ranges for 1960–1995.

The prevalence of gestational diabetes among the mothers was 5.5%, while approximately 20% of women had excessive weight gain during pregnancy, defined as more than 40 pounds. Among the women with gestational diabetes, 10.9% required insulin treatment.

The prevalence of overweight, defined as >85th percentile, among the children at any time between 2 and 10 years of age was 49.2%, while the prevalence of obesity, defined as >95th percentile, was 28.4%.

And tellingly, the prevalence of childhood overweight and obesity increased significantly across all maternal glucose and weight-gain groups (P < .0001 for each).

After multivariate adjustment for potential confounders, gestational diabetes increased the prevalence of childhood overweight and obesity (P < .0001 vs no diabetes), at a hazard ratio of 1.31 and 1.39, respectively.

A similar effect was seen for excessive weight gain during pregnancy with a hazard ratio, after adjustment, of 1.17 and 1.19 for childhood overweight and obesity, respectively (P < .0001 vs normal weight gain).

The attributable risk percentage for childhood obesity was 28.5% for maternal gestational diabetes and 16.4% for excessive maternal weight gain.

Overcoming Maternal Imprinting to Give Baby Best Start

Dr Hillier hypothesizes that what is underlying the association is that the baby is being "overfed," whether from excessive maternal weight gain or high maternal glucose due to gestational diabetes.

She said: "We think it's adapting to that overfed environment metabolically, after birth as well, so its metabolism is somehow switched to be more easily adaptable to put on weight, if you will.

"That's not to say that this is the only risk factor, in terms of maternal imprinting, but it's an important one because it's something that can potentially can be modified during pregnancy to give the baby a more normal metabolic start," she concluded.

This work is supported by a research award from the American Diabetes Association, and grant award from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, both to Dr Hillier. The authors declare that they have no relevant financial relationships.

Matern Child Health J. Published online May 6, 2016. Abstract

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