Childhood obesity has become a public health crisis in recent years. Studies suggest that early life influences (both during and after pregnancy) may affect a child's risk of becoming obese. Obesity puts children at higher risk for developing chronic disease later in life such as diabetes, cardiovascular disease, and high blood pressure.  The Healthy Start Study aims to investigate how the experiences of women during their pregnancies (e.g. diet, physical activity, smoking) and their environment during pregnancy affect their children growth throughout early infancy and childhood. This research will help to identify risk factors for childhood obesity and later life chronic disease. This will help us identify protective factors that help promote healthy growth of children.  1,410 ethnically diverse pregnant women were recruited from obstetrics clinics at the University of Colorado Hospital to participate in the Healthy Start Study. 

Collecting observational data about moms during pregnancy and their children throughout the first 3 years of life has allowed Healthy Start investigators to publish the following papers:


In this analysis of Healthy Start I data, Starling and collegues investigated the associations between how a woman's weight before pregnancy and her weight gained during pregnancy may affect her infant's size and fat mass (adiposity). Here, they found that women with obesity before pregnancy and women who gained more weight than suggested (relative to recommendations by the Institute of Medicine) after the first trimester give birth to larger babies. Specifically, these babies have greater adiposity when they are born.

What does this mean for you and public health?

These findings suggest that women who gain more weight during pregnancy than recommended by the IOM may experience overnutrition in utero. This overnutrition may increase an infant's risk of developing obesity through their early years of life. Long-term follow-up of participants of the Healthy Start Study is needed to further support these findings.   


Shapiro and collegues hypothesized that the relationship between a mother's weight before she becomes pregnant, and the size of her infant at birth (Starling et al., above) could be explained, at least in part, by maternal fuels in the blood (blood sugar and free fatty acids) and insulin resistance (decreased ability to regulate blood sugar), both during the first half and second half of pregnancy. The results of this analysis suggest women with obesity experience greater insulin resistance during pregnancy, which increases the levels of maternal fuels in the blood, and results in a larger baby with greater fat mass.     

What does this mean for you and public health?

Mild insulin resistance is a normal part of pregnancy, which prevents the mother from absorbing all of the nutrients that she eats or drinks, and allows for the fetus to receive these nutrients to promote growth and development in utero. However, women who experience obesity prior to pregnancy have higher insulin resistance than what is typical in pregnancy, which may result in much larger amounts of nutrients or maternal fuels reaching the fetus during development, therefore, leading to an in-utero environment of overnutrition. Knowing a mother’s weight and insulin resistance status could help in developing recommendations for a healthy diet during pregnancy, specifically, a diet that reduces the amount of sugar and fat received by the fetus.


Sauder and colleagues set out to test the hypothesis that greater maternal exposure to multivitamin supplementation would be associated with greater infant size at birth and an increased rate of growth in the first 5 months of life for both total weight and percent body fat (adiposity). The results demonstrated no association between prenatal multivitamin supplementation with increased infant size at birth, overall or within the first months of life. The results also showed that increased prenatal multivitamin supplementation was related to a slower relative growth in percent fat in infants up to 5 months of life.

What does this mean for you and public health?

From these results, we can infer that in a population similar to ours (Western USA), increased prenatal multivitamin supplementation during pregnancy may have no effect on infant body size. However, increased multivitamin supplementation may slow down the rate of fat growth in infants up to 5 months in life. 


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In this analysis, Sauder and colleagues tested the hypothesis that pregnant women who meet certain standards for diet quality, physical activity levels, and mental health status during early and mid-pregnancy are at a decreased risk of abnormal blood glucose levels. It was found that physical activity level was associated with reduced risk of abnormal blood glucose, while diet quality and mental health status were not associated with a decreased risk. When all 3 modifiable factors were examined together, pregnant women who met these standards were at a 73% reduced risk of abnormal blood glucose levels. 

What does this mean for you and public health?

These results suggest that pregnant women who maintain moderate physical activity, diet quality, and healthy mental health status in early and mid-pregnancy are at a lower risk of abnormal blood glucose levels, which in turn may reduce the risk of developing gestational diabetes. 


Shapiro and colleagues hypothesized that infants born to women with a poor quality diet (based on the Healthy Eating Index) would have higher fat mass (adiposity) at birth. In this analysis, maternal weight before pregnancy (e.g. obesity) was taken into account, so that the results would be applicable to all pregnant women, despite their weight status. The results of this analysis revealed that a poor quality diet during pregnancy was related to higher infant fatness, regardless of whether or not a woman entered pregnancy with obesity. In other words, a woman with a high quality diet gave birth to a baby with less adiposity, even if she entered pregnancy with obesity.

What does this mean for you and public health?

The results of this analysis highlight the importance of healthy diets during pregnancy for all women of all weights. 


The aim of this analysis was to estimate the relationships between second and third trimester maternal blood pressure changes (in women who do not have chronic high blood pressure) and infant birth weight and body composition. Results of this analysis suggest that greater increases in blood pressure (systolic and diastolic) are associated with increased risk of infants being born small for gestational weight. Furthermore, infant fat mass and fat free mass were lower among infants whose mothers had an increased blood pressure between the second and third trimester of pregnancy.

What does this mean for you and public health?

Research has shown that infants born small for gestational age are at an increased risk for future chronic disease. Increases in maternal blood pressure from the second to the third trimester of pregnancy may put infants at higher risk to be born small for gestational age, although long-term follow-up studies are needed to confirm this. 

 


Shapiro and colleagues hypothesized that increased intake of niacin (a form of vitamin B3), in addition to a high fat diet during pregnancy, would increase infant fatness (adiposity) at birth. Results of this analysis found no significant relationship between niacin intake during pregnancy and infant adiposity at birth, whether or not intake was addition to a high fat diet. It was found that a high fat diet, in general, during pregnancy was significantly associated with infant adiposity at birth.

What does this mean for you and public health?

The findings of this analysis demonstrate that maternal diet during pregnancy, especially with regards to high fat foods, may impact growth and development of the fetus and result in babies with greater fat mass. 


In this analysis, Harrod and colleagues aimed to test the hypothesis that infants who are exposed to smoking in utero will demonstrate "catch-up growth" (compensation for the growth restriction in utero, which is associated with smoking during pregnancy). Specifically, they hypothesized that babies born to mothers who smoked would have higher fat mass and fat free mass at birth and at 5 months of age compared to infants not exposed to smoke in utero. The results of this analysis showed that exposure to smoke in utero was associated with less fat mass and fat free mass at birth, therefore smaller babies.. However, at the 5 month follow-up, babies exposed to smoke in utero had significantly greater fat free mass than babies who were unexposed to smoke, suggesting there is rapid postnatal growth for exposed babies.

What does this mean for you and public health?

Findings in previous studies suggest that "catch-up growth" is associated with an increased risk of early-life developmental changes that predispose infants to obesity later in life. The results of this analysis may indicate that maternal smoking while pregnant may increase the risk of "catch-up growth," and therefore, the risk of obesity later in life.