Far too little is known about the safety of medication use during breastfeeding – and it's time to get some answers, experts say.
It's a critical gap, given that breastfeeding is the best source of nutrition for babies – and moms are encouraged to do it. But when a woman has questions about the safety of any medication she's taking, doctors typically have little evidence-based advice to offer.
That's according to a perspective piece in the New England Journal of Medicine highlighting the dearth of evidence on the matter.
"The point of this article is to raise awareness of the issue," said co-author Dr Catherine Spong. "We need to encourage more research."
Spong is vice-chair of obstetrics and gynaecology at the University of Texas Southwestern Medical Center in Dallas.
The need for this kind of research has been recognised for decades, Spong and colleague Dr John Byrne pointed out. In the 1980s, separate reports from the US Department of Health and Human Services and the American Academy of Pediatrics highlighted the gap, for example.
But it took 20 years for the US Food and Drug Administration to issue guidance for industry on how to conduct studies of breastfeeding women. And it was only last year that a federal task force published a report with recommendations on research needs for pregnant and breastfeeding women.
The recommendations said that those women should be included in drug research studies, unless there is "scientific justification" not to – and that regulatory barriers to their participation should be removed.
Change is coming
"There's been a misperception that you can't do research in this population," Spong said. And that has denied women valuable information, she added.
It's not that studying breastfeeding women is too hard, said Christina Chambers, a professor of paediatrics at the University of California, San Diego (UCSD).
"It just takes time and money," she said.
Chambers is also president of MotherToBaby, a free service of the non-profit Organization of Teratology Information Specialists. It provides women with information on medication safety during pregnancy and breastfeeding.
Chambers said she hopes the new article brings attention to the lack of research. But she was also optimistic that "hopefully, now, a sea change is coming".
Chambers is programme director of a breast milk repository at UCSD that is providing the first-ever research database of breast milk samples. It will allow scientists to study, among other things, medication safety.
Recommendations where possible
A first question is whether a given medication even gets into a woman's breast milk. And, if so, at what amount?
"Then, what parents really want to know is, what does it do?" Chambers said.
Are there any short-term effects on the baby, like fatigue, irritability or diarrhoea? Beyond that, there are the longer-term questions of whether medication exposures can affect growth or brain development in any way.
Even if a medication did have small effects, Chambers noted, that would have to be weighed against the benefits of breastfeeding.
For now, both Chambers and Spong recommended the website LactMed as a good resource on medication safety during breastfeeding. It's run by the US government and pulls together scientific evidence on individual medications – giving recommendations when possible.
But as of November 2018, only 2% of products on the site had recommendations based on "strong data," Spong said.
She stressed, however, that the intention is not to scare women away from breastfeeding – but to point to a research need.
"I don't want anyone to come away from this thinking, 'I shouldn't breastfeed,'" Spong said.
Chambers agreed. And there are certain reassurances in what scientists know at this point, she noted.
According to LactMed, for example, the painkiller ibuprofen (Advil) gets into breast milk at "extremely low levels" – much lower than the dose that would be given to an infant. So it's considered a "preferred choice" for nursing moms who need pain relief.
Chambers pointed to the monoclonal antibody therapies used for conditions such as rheumatoid arthritis and Crohn's disease. They are large proteins that have to be given by IV because they cannot be absorbed orally, so experts believe they are unlikely to be a risk to breastfed babies.
Any woman with worries over her medications should talk to her doctor, Spong said.
To learn more, Chambers added, they can contact a MotherToBaby counsellor for free.
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