The sooner a new mother goes back to work after giving birth, the less likely she is to breastfeed her baby, researchers have found.
Mothers in the study who went back to work within six weeks were less likely than other women to start breastfeeding - and when they did start, they were less likely to continue.
By comparison, moms who stayed home for at least nine months, or even 13 weeks, were more likely to predominantly breastfeed their babies for three months or more.
Slideshow: Celebs Who Promote Breastfeeding
There are many reasons why returning to work can make it harder for women to keep breastfeeding, said study author Dr. Chinelo Ogbuanu of the Georgia Department of Community Health.
For example, she said, the more women breastfeed, the more milk they produce. When they are separated from their babies during the day, their milk supply may start to dwindle. And when it comes to milk production, "no matter how good a breast pump is, it's not as effective as an infant," Ogbuanu told Reuters Health.
Consequently, she suggests that women try to take all their maternity leave at once, rather than breaking it up, and find ways to keep their baby close to the workplace during the day, perhaps at a nearby daycare, so they can breastfeed during work breaks.
"We would encourage all women to attempt to breastfeed and continue as long as they can," she said.
And if they have to return to work and can't breastfeed during the day, regular pumping will ensure their supply continues, Ogbuanu added. "Even if you have 10 minutes, take it and pump and come back."
Research has shown that breastfed babies have lower rates of a number of pediatric diseases, including eczema, middle-ear infections, lower respiratory tract infections like pneumonia, asthma, type 1 diabetes and sudden infant death syndrome
Recently, a study estimated the U.S. could save $13 billion per year, as well as prevent 911 annual deaths, if nine of every 10 new mothers breastfed exclusively for six months, as is generally recommended.
Currently, just seven of every 10 women in the U.S. breastfeed their babies at all and just three of every 10 continue for a full six months, according to the Centers for Disease Control and Prevention.
To investigate the relationship between breastfeeding and work, Ogbuanu and her co-authors reviewed information collected from 6,150 women who worked before giving birth.
In interviews conducted nine months and two years after their babies were born, the women reported how long they had breastfed and when they returned to work.
It turned out that women who did not go back to work for at least nine months after giving birth were more likely to have started breastfeeding than women who said they'd gone back in six weeks or less. Specifically, about seven of every 10 moms who were still home nine months later had tried to breastfeed, compared to six of 10 who went back to work within one to six weeks after delivery.
Even moms who stayed home for at least 13 weeks appeared to have an easier time of breastfeeding - more than three out of 10 said they predominantly breastfed their babies for at least three months, compared to less than two of every 10 moms who went back to work within six weeks, the authors report in the journal Pediatrics.
However, the authors did not find any relationship between breastfeeding and total allowed maternity leave, paid or unpaid. The findings focus instead on the amount of time women took off before returning to work. Some women, for example, who have 12 weeks of maternity leave might not take all of it right after the baby is born. Some of them might return to work sooner, explained Ogbuanu. Others might have had to use some of their leave time before giving birth, if they needed to be on bed rest, for instance.
In general, Ogbuanu and her colleagues believe, if new mothers delay their return to work, then duration of breastfeeding among mothers in the U.S. may lengthen.
"I think (time off and breastfeeding) is a really important issue, and I'm glad they're addressing it," said Dr. Hawley Montgomery-Downs of West Virginia University, who did not participate in the study.
But Montgomery-Downs told Reuters Health that the lack of a relationship between breastfeeding and total maternity leave makes the data somewhat confusing. "Based on their findings, I would not necessarily say going back to work causes some women to stop breastfeeding," she said.
Still, other studies have suggested there is a relationship, she added. Ideally, she said, researchers will one day conduct a large-scale study in which they compare breastfeeding habits between similar women given long and short maternity leaves, "and see what happens, really get at it from a cause-and-effect perspective."
In the current study, the authors used statistical tools to try to eliminate the influence of factors that could affect a woman's ability to nurse, such as her age, ethnicity, income, and the child's birth weight, for instance. One factor they couldn't control for, said Ogbuanu, was the mother's intention to breastfeed, and it's possible that women who knew they wanted to breastfeed "would find avenues to stay home longer."
In the meantime, it actually behooves companies to try to help women breastfeed, according to Dr. Saundra Glover of the University of South Carolina. Glover, who worked on the study with Ogbuanu, told Reuters Health that nursing helps reduce illness in kids, which means fewer days parents have to take off from work to tend to a sick child.
"We need to build a business model where employers see the benefit of providing leave," she said.