Yes, especially if your baby is in daycare, according to a new research study published in the Archives of Pediatrics & Adolescent Medicine.

Of the 8,150 9-month-olds studied in the research—conducted by Juhee Kim of the University of Illinois at Urbana-Champaign and Karen E. Peterson of the Harvard School of Public Health—55.3 percent were in regular non-parental care, half of them full-time. (Non-parental care includes both daycare and care by other members of the family).

Around 40 percent of those children in childcare started going when they were younger than 3 months. That group was less likely to have been breastfed, and more likely to have started solid foods early (before the age of 4 months).

Infants in part-time care weighed around 0.4 more pounds in the first 9 months than babies in parental care. Even those who were cared for by relatives still were less likely to breastfeed, more likely to be given solid foods early, and weigh around 0.35 pounds more.

The study’s conclusion? “Child care factors were associated with unfavorable infant feeding practices and more weight gain during the first year of life in a nationally representative cohort,” write Kim and Peterson. “The effects of early child care on breastfeeding and introduction of solid foods warrant longer follow-up to determine subsequent risk of childhood overweight.”

Overweight children are more likely to develop type 2 diabetes, high blood pressure, high blood cholesterol, joint problems, asthma and sleep problems (If you’d like to learn your child’s Body Mass Index, there’s a simple calculation here.)

Why is this happening? As you might expect, it’s complicated.

Maternity leave? What maternity leave?
For one thing, it’s hard to expect women to keep breastfeeding when they only get weeks of maternity leave.

Unlike other developed nations, the U.S. offers no national paid maternity leave. Australia doesn’t offer paid leave either, but it does have a year of job-protected leave. Under the U.S. Family and Medical Leave Act, some Americans get 12 weeks of unpaid job-protected leave—it only covers larger companies. (To see your state’s legislation on maternity leave, go here.)

A 2005 Harvard University study showed that 163 out of 168 nations had some form of paid maternity leave—which left only Australia, Lesotho, Papua New Guinea, Swaziland and the U.S. behind.

Perhaps the U.S. should follow the lead of Norway, where mothers are given 53 weeks of leave at 80 percent pay (and a guarantee their job will still be waiting for them), and fathers are given five weeks of paid paternity leave. Not surprisingly, Norway is seventh on the list of 21 industrialized nations for child wellness; the U.S. is second to last.

Also in Norway, 98 percent of women breastfeed immediately following birth, 90 percent are still breastfeeding at 3-4 months, and 75 percent are still breastfeeding at 6 months. (Keep reading for the U.S. numbers, which lag far behind.) Not only that, working women who breastfeed get 2 hours of leave time a day.

The American Academy of Pediatrics recommends breastfeeding exclusively for the first 6 months, to continue nursing for at least a year, and “thereafter for as long as mutually desired.” Alex Kojo Anderson, assistant professor of foods and nutrition at the University of Georgia, says that it’s unfair to expect American mothers to successfully follow those guidelines when they have to return to work so quickly.

“I really like the work ethic in the U.S., but it falls short when it comes to maternity leave,” says Anderson, who is from Ghana. “We’re saying you need to exclusively breastfeed for 6 months. How is the mom going to do that?

Well, by pumping breast milk at work, of course, you might be thinking—but it’s not that simple. Breastfeeding moms who pump know that in order for your milk to letdown, it’s essential to be relaxed. For women with their own offices in a supportive, encouraging work environment, it’s not so hard—but it’s a different story for those forced to stressfully pump in their cars in a parking lot, in a bathroom stall or behind a small office partition.

“There’s no excuse for (large companies) not being able to provide one closet in one huge tower, and even one pump for the mothers to use,” says Donna Jenkins, a registered nurse and international board certified lactation consultant at St. Mary’s Hospital in Athens, Ga. “It’d be a drop in the bucket.”

She’s optimistic that more employers will come around. In Georgia, “it’s a state law that (employers) have to allow time to pump, at least 15-20 minutes, 3 times a day,” she says. “That will help change things.” (You can find legislation for your state here.)

Also, she notes that insurance companies are starting to cover the costs of pumps more, recognizing the proactive ways breastfeeding keeps both mom and baby healthy, leading to more productivity in the workplace.

“If employers can pick up on the idea, when they start hearing the cha-ching in all of this, they’ll start supplying a closet and a pump,” says Jenkins.

A less-than-stellar report card
Remember those rates for Norway? Let’s see what’s happening in the U.S.

According to the Centers for Disease Control and Prevention, the goal for the U.S. in 2010 is for 75 percent of women to breastfeed in the hospital following delivery, 50 percent to breastfeed for 6 months, and 25 percent to breastfeed for a year. (There’s no stated goal past the 12-month mark.) In 2002-2003, 70.9 percent of women breastfed for any amount of time in the hospital, and 62.5 percent breastfed exclusively; 36.2 percent breastfed for any amount of time for 6 months, and only 14.2 percent did exclusively; 17.2 percent breastfed for any amount of time for a year; and only 5.7 percent breastfed for 18 months.

The CDC issues a breastfeeding report card annually. On it is something called an mPINC (Maternity Practices in Infant Nutrition and Care) score, which measures the extent that each state’s birth facilities support breastfeeding. The maximum score is 100, but the closest any state got was 81—that would be New Hampshire and Vermont, tied. The lowest? Arkansas at 48.

That doesn’t mean that people in Arkansas aren’t breastfeeding, though. If you look at the report card’s outcome indicators, the U.S. national average for women who have ever breastfed is 74.2 percent. The number consistently drops, however, as you look at the national average of how many are breastfeeding at 6 and 12 months (43.1 and 21.4 percent, respectively), and even more for people breastfeeding exclusively at 3 and 6 months (31.5 and 11.9 percent).

“The American culture doesn’t recognize breastfeeding as a norm,” says Anderson. “I was in Africa this summer. In Ghana, you see women breastfeeding everywhere. It doesn’t offend anybody…we need to sensitize people over here.”

A family of support
According to his own research in the Journal of Human Lactation, Anderson says mothers who live with the child’s grandparents are less likely to breastfeed exclusively—because the grandparents pass on false information from their generation of parenting, believing that breastmilk “is not enough” to properly nourish the child.

Jenkins points out that many parents of today’s breastfeeding mothers did not breastfeed themselves. Some grandmothers, knowing now that they were misinformed, may have guilt over their decisions not to breastfeed. Or they may still believe that breastfeeding is second best to formula and solid foods. Either way, rather than encourage any interest in breastfeeding, they might tell their daughters, “That’s the way we did it, and you turned out OK,” Jenkins relates.

“I don’t think they should feel bad,” says Jenkins. “That’s wasted baggage and guilt.” A simple response to such a well-meaning grandparent would be: “’Now we know different,’ and we go on from there,” says Jenkins.

Overfeeding and the problem with early solids
When multiple babies in a daycare are crying, says Anderson, workers will often soothe them in the most efficient way that will get quick results: they feed them, even if the child isn’t crying out of hunger.

“They’re all crying at the same time…so they push food on them to comfort them,” he says.

Formula-fed babies often eat when they may not be hungry, says Jenkins.

Breastfeeding mothers have an advantage in determining whether their baby is truly hungry by their latching behavior. With bottle-feeding, if a child is given a bottle when he or she isn’t hungry, “The kid has no choice (but to eat),” says Jenkins. “The bottle is in there, stimulating the roof of their mouth—the bottle just keeps flowing.” It is not uncommon for Jenkins to see formula-fed babies who are overweight.

Another problem is that some daycare workers are still squeamish about handling breast milk, says Jenkins—they think of breastmilk as not much more than bodily fluids. And even though she’s seen improvements in their reception of breastmilk in the past 5 or so years, “there’s still a lot of resistance,” she says.

What about that group of infants in the study being given solid foods before they were 4 months old? The AAP recommends starting solid foods at around 6 months. Delaying solids that long gives better protection from illness (assuming the child is breastfed), more time for the baby’s digestive system to mature, decreases the risk of allergies and protects against anemia, among other things.

What some women might not realize is that the introduction of solid foods not only affects their milk supply, but might lead to early weaning.

When a baby gets a first taste of solid food, “it changes their whole world,” says Jenkins. “As you start introducing solid foods, that’s the start of the weaning process.”

One solution: peer education
How can breastfeeding education reach these parents, family members and daycare centers? Anderson suggests peer education as one tool, but it must be done carefully—the peers must truly be peers, either mothers themselves or people with experience working in childcare. It would also help if the educators are paid rather than volunteers, he says.

The effort must be complete, he says: “Peer educators must be involved with not just the mother, but grandparents and anyone around the mother.”

Jenkins suggest that grandparents be invited to come along with the parents to breastfeeding classes, or to any childcare class that happens to include information on breastfeeding classes. “Then you’re teaching the grandmothers with the mothers,” she says.

State and regional breastfeeding coalitions are also a good resource, she says, for reaching out to daycare centers.

Still, suggests Anderson, there’s a lot of work to be done to make this country truly supportive of breastfeeding.

“Here, I really, really respect women who breastfeed a year or longer,” he says. “It’s really tough in this country.”